F-stops don't directly refer to the iris size but the ratio of the focal length to the entrance aperture. eg. 50mm f/1.4 has an entrance pupil of 50mm÷1.4=⌀35mm. By changing the focal length, the F-ratio will also change. eg. 50mm f/1.4 & 0.71x, the entrance pupil remains ⌀35mm while the focal length becomes 35mm. N=(50mm×0.71)÷⌀35mm=f/1.0
Yes, if you are considering the addition of the speed booster to form a new optic at a different focal length. I’m referring to people who have said a 50mm lens with speed booster taken in APS-C crop will have a shallower depth of field than using that same lens without the speed booster with the full width of the sensor, assuming a wide open aperture in both instances
If one were to compose the same portrait using the same lens with and without the speed booster on a crop sensor, and if the portrait were to remain constant, the photographer will need to move closer when using the speed booster. The net result is a more blurry depth of field. So while you are correct, technically, people tend to make assessments, not on technicalities but on compositions, so all compositions being equal one will get more bokeh with the same lens,
Well, first I would point out that distance to subject is also a technicality. But this video is several months old and at the time there were no APS-C sensor cameras on the RF mount. That is why I specifically reference comparisons between shooting full frame without the speed booster and in a cropped sensor mode with the speed booster
yes and no... f-stop measures the amount of light able to pass through the lens. t- stop is the amount of light that comes out the other side. a speedbooster squeezes more light into the area of the lens that will hit the sesnor. canon is justified in doing what they do. it pretty much does make your lens faster. this is also why the background blur changes.
Yes and no… F-stop is a ratio of the size of the opening of the aperture to the focal length. It does not measure light. It does affect the potential of how much light can pass through the lens. A speed booster doesn’t not do anything “into” the lens. It concentrates light that comes *out* of the lens. If you want to think about your 50mm lens + speedbooster as now being a new, different 35mm lens, then yes, it would be faster than an equivalent 35mm lens. However, the background blur does not change. A 50mm f1.4 lens shot wide open on the full sensor width, without speed booster, has the exact same depth of field and background blur that you get from that same lens wide open with a speed booster using an APS-C crop. The background blur does not change. This is the confusion I’m trying to clear up
@@JustinMyersPhoto Canon isn't the problem. It's RUclipsrs who don't understand F-stop and crop equivalence. An EF 50mm F1.8 with this speedbooster will indeed give you the same image (same bokeh and light gathering) as a theoretical EF-S 35mm F1.26, so why should the display read anything else? The problem is when people compare between crop and FF. They forget that the 50mm F1.8 on a crop sensor (without a speedbooster) gives the image equivalent of 80mm F3 on a FF. Forgetting that 1.6x makes 0.71x look powerful...
@@masina9447 yes, see that’s the thing: their cameras don’t display equivalence. A 35mm EF-S lens, is a 35mm focal length regardless of the sensor it is put in front of. Using a 35mm EF-S lens would yield the same field of view on a full frame sensor as a 35mm EF lens. The only difference being that the edges of the sensor would be dark since the EF-S lenses are designed to project onto a full frame sensor. And despite both a 35mm EF and a 35mm EF-S lens on an APS-C sensor giving a full frame equivalent field of view to a 56mm, they are both still displayed on the APS-C camera as 35mm, because the sensor size doesn’t change the focal length. Canon treats speed boosters and extenders as creating a new optic when paired with a lens, which is fine, but like I said it causes confusion on the topic of focal length and sensor size, where there is already rampant confusion.
Regarding your comments about speedbooster & optics/F-number. (I never heard of this optic for cameras.) F-number is NOT the aperture; it is the RATIO of focal length to aperture diameter. The reason this is important is that any lens with any focal length will give the SAME light intensities at the sensor viewing the same scene. You need know ONLY the F-number to set exposure. (There is math I can go into if your interested how this works.) The focal length sets the SIZE of the image when viewing a given scene; size is proportional to focal length. Now you introduce optic in the path that reduces the size (since you say brightness goes up by 1 F-stop, the size must by reduced by the square root of 2, or about 0.7). What has happened is that the effective focal length of the lens/booster combination has been reduced by the same ratio. So if you were using 50mm lens, with the booster it becomes about 35mm lens ("wider angle" in that image is smaller, but cropped to the same angle of view). The aperture has not changed, so the F-number HAS been reduced by that same factor. So I allege the statement made by Cannon about F-number is CORRECT, because that RATIO changed. If you using an old-fashioned light meter & using camera in manual mode, you would adjust the wheel on the meter to the F-number 1 stop faster to read out the proper exposure time. In essence, the F-numbers on the lens setting ring are all reduced by 0,7. I assume you are familiar with "teleconverters" that photographers & astronomers use, to crank up magnification. These INCREASE F-number (you must up your exposure time to get photo). They are used when light is available & you don't want heavy, expensive "long" lens. What this thing does is the opposite. Couldn't you use a "shorter", wide-angle lens instead? (Perhaps it is because that lens, being able to expose the full frame, is more expensive?)
I understand where you’re coming from, but you’re confused on a few points. The F-number is a ratio of the size of the aperture to the focal length of the lens. The size of the sensor does not affect either of those. For instance, if you were to put a full frame lens on an APS-C camera, it would not change the maximum aperture. What you’re getting confused with is “equivalent aperture” which is just an attempt to help shooters have a frame of reference between sensor sizes. As far as F-number allowing you to dial in exact exposure, that’s just a misunderstanding. As I said in the video, as well as what you already said in your comment, f-stops measure aperture size to focal length, not light transmission. And again as I pointed out in the video, there are a lot more factors involved in actual light transmission and, thus, exposure. Lens elements, lens coatings and more can affect light transmission. For an extreme instance of this, look at the Canon RF 85mm f1.2L vs Canon RF 85mm f1.2L DS lens. The exact same f-stop gives about a 2 stop exposure difference between the lenses. I understand where your confusion comes from with light meters, but those are not made to get you exact exposure. They were designed to get you as close as possible in a time where you couldn’t see your exposure until you got back to the dark room. You’re similarly confused with what you’re supposing about focal length. Focal length is, again, an optical measurement and has nothing to do with the size of the sensor. Putting a 24mm full frame lens on an APS-C camera does not change the focal length. I understand that, again, people often refer to “equivalents” between sensor sizes, but, again, that is just a reference point for similar field of view. Different focal lengths have different aesthetic characteristics based on their focal lengths, that doesn’t change with the size of the sensor. The sensor just records different portions of that. I understand that it’s confusing, hope that helps 👍
@@JustinMyersPhoto I understand the sensor has nothing to do with the light intensity delivered by the lens (whether some of it misses the sensor or not). Regarding F-number, I also understand the "T-number" as F-number fudged upward by light loss factor (this is usually negligible on modern expensive lenses except the most exotic). I am not confused about focal length! Focal length & distance alone determines the size of the image, period, whether sensor is there or not. When you point a lens at a scene, focal length alone determines the area into which the light is delivered. I never declared that installing a lens on a different camera changed focal length! But when you introduce another optic between the lens & the sensor, that optic becomes part of the lens & ALTERS its characteristics. Specifically, the speed booster reduces the focal length of the combination. Try the following experiment. Put 50mm lens + 1 stop speed booster on camera, put on tripod & photograph scene. Repeat this putting 35mm lens on & photograph same scene again. (Make both photographs full-frame, do not crop.) I allege the objects in the photos will be the SAME SIZE. You will be able to overlay the 2 photos & match them up in the central area. The only difference will be the dark border on the photograph taken with the speed booster. If the F-stop of the 35mm lens were set 1 stop faster than that of the 50mm lens, the brightness of the 2 images will also match in the central area.
@@bpark10001 okay, I see where you’re coming from, presuming that a speed booster attached to a lens becomes part of the optic, rather than a post-optic modification. So, where you’re coming from, you’re not looking at it as a comparison of the full frame image of one lens, to the APS-C image of the same lens + speed booster, which is where the confusion has been online. Which has been centered around depth of field gained/losses with a speed booster in APS-C vs the same lens on full frame without the adapter. People have thought that using the speed booster + 50mm at max aperture in APS-C mode would give them a shallower depth of field than using that same 50mm at max aperture without the speed booster using the full sensor width, which isn’t the case. I don’t take issue with anything you are saying. I think we’re just talking about it differently. Definitely appreciate the input 👍
@@JustinMyersPhoto Regarding depth-of-field, reducing focal length increases it, & decreasing F-number decreases it. I would expect there to be little change as the 2 effects would tend to cancel. Regarding the comparison I advocated making, it would be neat for you to set up & publish the 2 photos. I suspect it would do much for educating the public, more so than just explaining. If you include foreground & background objects, some well lit & others not, & do same exposure on both, we could see the depth-of-field & F-number effects.
@@bpark10001 I actually did test it. You can see some of the side by side clips in the video section. Like I said, the confusion I was addressing involved depth of field with a lens used on full sensor width without speed booster vs depth of field with the same lens in APS-C crop using the speed booster. There is no change in depth of field there. I do agree, a video about the test specifically would be interesting, but I would hesitate to do it with photos. I feel like that might add to the confusion where people might think it could be useful for photography. Again, they would be getting the same image as using the lens without the speed booster on the full sensor width, except that the image is then only projected onto the center, APS-C size of the sensor. All they would be doing is reducing the resolution of the image at that point
Hey Justin, thanks for this. I really appreciate your clear explanations and, I share your frustration that some reviewers just get it wrong with the facts on what a booster physically can and can't do. I think I'll get a viltrox .71x for my RP@4K25p, and in recent videos I have been using this camera for detail work with manual focus, so AF issues not an issue. I use the R6@4K50 with EF 17-40 for FF footage with me talking so that's where the AF is critical. (Will probably get a RF16/2.8 soon too). The one problem I have observed with the RP in 4K mode is rolling shutter. It can be avoided by using exposure 1/200 or faster, which is okay for most of my work, but then with fast movement it can appear like a series of stills rather than a video with movement. Anyway thanks again for your insight and clarity. If you ever get a bonsai I hope I can repay you the favour !! 😁
Hey, glad you enjoyed it! That is another thing I forgot to mention about the 4K on the RP, the terrible rolling shutter performance. But if you understand what you’re going to get and have a workaround that suits you, the speed booster is interesting at this price
have this exact same speedbooster, Viltrox Ef-R3 and I have autofocus issues when a subject is not close to the lense and I'm on 24mm, when i zoom in to 70mm the autofocus starts working...I have it paired with EOS R
I can't tell you how many arguments I got into out here on the internet about this very thing. All one has to do it shoot the same subject (same distance, same parameters) wide open without a speed booster and then shoot the same lens wide open with a booster and then compare the photos. I always tell people bokeh and depth of field are are driven by lens characteristics, and these things have zero/nothing to do with sensor size.
Shooting in 4k 60p in crop mode on the R6 with the speedbooster was a really interesting test, thank you for that! I think that would appeal to people in the wedding industry that are nervous about the overheating in FF 4k 60p, but want the "FF Look" still.
Hey can you tell me what grip or L bracket you were using with the arca Swiss plate on both vertical and horizontal do r the EOS r Body been looking for one that at least covers the whole body when adding the bracket
Nice job as usual Justin. I wasn’t aware that the 4k crop mode didn’t overheat as easily. This video was very helpful. I’ll be using this to my advantage doing weddings… pretty much my primary case scenario where I see the overheating warnings on my R6.
@@JustinMyersPhoto I’m 50/50 with RF glass. I have the RF 35, 50, Samyang 85 and 24-105 f4 L. In terms of EF glass I have the EF 17-35 L, 24-70 L, 50 f1.4, and 100 mm L macro. I rent the 70-200 when needed (rarely). So I use both EF and RF glass as needed. I love the RF 35 for video. It’s on my R6 50-60% of the time for video. Also use an RP for video as a B cam. I’m gonna test out the crop mode this week using my existing glass to test out the overheating issue in crop mode. I’ve got range from 17 to 105mm with the glass I have so I’m flexible and none of my pieces are throwaway lenses.
thanks for the video Justin. So now with the R7 in play, would you recommend getting a speedbooster to give that full frame feel for photography? I know its not affecting the aperture still but the light and framing will be more in line with a full frame than aps-c wouldn't it?
Well, you actually can, but I don’t see it being particularly useful. You would only be able to use it on the R5C when shooting in one of the sensor crop modes. There’s not a whole lot of advantages to doing that with the R5C vs just shooting with the full sensor. It wouldn’t noticeably affect framing / field of view, so I can’t think of any reason to use a speedbooster with the R5C in crop mode. Instead you can just use a regular EF-RF adapter and shoot in full sensor mode
Thanks for the video, Justin. I have one question: would you recommend a speed booster to use on a URSA Broadcast G2? Would it be a good idea to use Full Frame lenses on the Broadcast G2 with it's Super 35 sensor?
Really tempted to pick one of these up mainly to use with a 1.4 lens to get insane low-light capability. I use the RF 24-70 with my R6, but occasionally use adapted EF (Sigma 24 1.4, EF 16-35, etc.). I might go with the PRO version of the EF-RF just for the security of that locking collar when using the combo on a gimbal.
@@jej3films okay cool. No, I don’t really have any lowlight examples. My primary use case was to match the full frame image in a crop sensor mode. I didn’t really test it for lowlight, but it literally just gives an extra stop of light. So, whatever ISO you’re at wide open, you would shoot half that ISO value to get the same exposure wide open with the speed booster
While not the same, I have the EF to EF-M Viltrox speed booster. I use it with my 24-105 f4L for video (and photos) with very nice results. Not as good as that lens on my RP but not much worse either (I really can't tell most of the time). I don't have an R5 or R6 to compare with, but I am looking at the R6 in the near future. I've noticed that my M50 also reports the lens/speed booster aperture at f2.8 not the f4.0 of the lens. I wonder if Canon is programming their cameras to show "favorable" apertures when using image modifying attachments, as I see that my macro lense doesn't seem to record aperture properly at high magnification with extension tubes (at 1-2x life size f2.8 on camera should be about f5.6 if I remember the calculations from the film days where you had to overide exposure settings when using bellows or tubes), hmmm.
Nice! I never owned an M series camera, so didn’t get to try any of the speed booster options for that. Ya, as far as displaying the aperture correctly/incorrectly with any type of modification attachment, I think it’s just a misguided attempt at when and what to change in displays. Can’t speak for sure about extension tubes, because I don’t use them, but the speed booster thing is definitely their attempt to tell the user that the exposure is brighter. But it doesn’t make sense to do it that way and it has caused a lot of confusion unfortunately
I'm a bit lost when you say it doesn't make sense for photography. I'm thinking of getting a crop sensor camera and using this to get back the focal length of my FF lenses. Doesn't that make sense?
If you are looking specifically at the R7 or R10, it definitely does make sense. Those are the only two crop sensor photo cameras from Canon with the RF mount. When I made this video, there were only full frame RF mount photo cameras, that’s why I said that it didn’t make sense at the time. Now with the R7 and R10, this style of speed booster does become much more interesting
@@ArcanePath360 I haven’t used the APS-C RF mount cameras yet, so I don’t have a way to accurately test sharpness on images more than about 13 MP, but I didn’t see any dramatic loss in sharpness from the speed booster
@@JustinMyersPhoto Okay, thanks. Everybody still waiting on that R7 to get released properly. In the UK it's hit waiting list and hope. But we'll be lucky to get our hands on it this side of summer
It's not Canon cameras. My Panasonic Lumix GH5s did the exact same thing by displaying the "adjusted" f-stop. I think everyone knows what it is doing, it's just easier to say that it gives you a 1 stop gain in light.
Yes, I mentioned it somewhere in the video. It’s about 2x the price of this one though, so I definitely can’t recommend it at this point unless someone already has it. Do you shoot with it?
@@JustinMyersPhoto yes I have the metabones one. I got it when I had the eosr and it works great. Metabones is very good with keeping the firmware up to date. I haven’t had any issues with color as you mentioned you had with the viltrox. I did a lot of research on Viltrox speed boosters when I was thinking of getting one for the m6 mkii camera I have. As you say the Viltrox price made it a intriguing option vs the metabones which is for the m series cameras much more expensive than the Viltrox. As I did my research and dug deeper I found reviews saying not to get the Viltrox as the quality veries greatly from unit to unit and the image quality is not on the level of the metabones. The metabones cost 479.00 so as you say the Viltrox is cheaper, but you also have to ask yourself why is it cheaper? I tried both speed boosters on my m6 mkii and the metabones was noticeably better in build quality and image quality. 479.00 seems to be metabones price as my speed booster for the eosr camera was that price too. I agree though if you don’t mind a image quality hit and possible quality issues, the Viltrox is the answer. But if you want the best possible image quality and excellent build quality then the metabones is definitely the better choice. I haven’t tried Viltrox speed booster for the r series cameras so maybe they are different now. This is my opinion of coarse based on the research I did, others may feel differently. Excellent video as always Justin.
@@wadesweeney2200 ya, when the metabones came out back then, it was the obvious choice, because it was the only choice. Now, it’s the same price as the first party Canon speedbooster. It does have very good image quality, but it’s about the same as the Viltrox and neither are quite as good as the Canon version. I definitely don’t think this Viltrox RF speedbooster is a “hit” in image quality compared to the metabones. The price difference is pretty clearly based on the electronics being copied from the Canon speedbooster, so they don’t have the R&D costs that Canon and metabones had. Like I said, at the time when you got it with the R, metabones was the only choice. Now, the Canon version is definitely the highest quality option, although they are all three pretty close. If someone is getting a third party RF speedbooster now though, it’s kind of hard to suggest paying double the price. I’d say to go Canon brand now if they are willing to pay that price Thanks for watching the content!
I have never overheated with either of my r6's in 4k all day so I am surprised to still hear that people have that issue. Interesting video as well here, I didn't now they made a speed booster for these cameras. I just use the EF to RF adapter with no glass. Both the Canon and Vello are great.
Ya, as I mentioned, I’ve never had an issue with the R6 overheating during my actual use. As I said, the speed booster was developed for the C70, it just works with the mirrorless cameras as well, seeing as they use the same mount. The speed booster would only be for using the crop video modes of the mirrorless cameras, as I mentioned in the video
Definitely not my testimony. I frequently have the overheating warning during weddings. Just having the R6 on during the day creates overheating issues for me.
@@justesmond dang, I run two at wedding and never had an issue luckily. Hopefully they don’t cause you too many issues in the future. Maybe they’ll bring out a firmware update to fix it or battle it at least.
@@DLivingston The crazy thing is my camera is up to date with the latest firmware so it should not be having those issues. But I am in south FL and heat and humidity are a part of my everyday environment. I’ve had to take out the battery from time to time when not shooting to allow the camera to cool. It just creates a worry that I’d rather not have to think about at all on a wedding shoot. And turning the camera on and off could make me miss something important. So this crop mode discussion that’s the topic of this video is definitely on my radar to try to see if I can record without worrying about overheating.
Canon really shoot themselves in the foot with their greedy pricing. Just waiting for a 3rd party battery grip to come out of the R6 that isn't a ridiculous price as well now. Thanks for explaining how the speed booster works with brightness. It makes sense now. It is misleading that it changes the f stop. It's more like increasing the ISO without the extra noise. That would have been a better description, or maybe just light intensity is increased.
Its not a "booster" lol its a reducer. Im just sayin. Speedbooster is simply the branded name Metabones gave to their focal reducers. But its not a Viltrox Speedbooster. It's a Focal Reducer. I understand most people probably understand this, it's just that words mean things :P In addition, to that, ALL other manufacturers account for this extra light the same way. By applying it to the iris. There is no other way to account for it. It's only done this way for the end user to get a proper exposure. Accounting for it by way of Shutter speed makes no sense because it would affect your motion blur and accounting for it by way of ISO makes no sense because ideally you'd like to shoot at the cameras native ISO. The ONLY other option is to account for it by way of Iris, because since the reducer isnt physically opening the iris wider (as you stated), it's not effecting your image visually, while the two other methods of accounting would.
Wow, it’s hard to get so many things wrong in one comment, but I’ll try to help you figure things out lol. Viltrox’s products are, in fact, called speed boosters by Viltrox and are marketed and labeled as such on their website. A quick Google search could have saved you that embarrassment. Just saying. Also, your argument behind why iris is the way that a difference in exposure should be noted, is actually exactly why it doesn’t make sense to change the displayed f stop. As you stated: “since the *speedbooster* isn’t physically opening the Iris wider, it isn’t *affecting* your image visually”. Opening the iris wider would, in fact, affect your image visually, which is exactly the problem with changing the displayed f stop when the Iris opening is not being changed. As I explained in the video, f stop is a measurement of how wide the aperture is opened in relation to the focal length of the lens. A change in light transmission through the lens does not, in and of itself, need to be noted by shutter speed, ISO, and/or f-stop. If you shoot an image outside in broad daylight with no extra lighting, and then come back at night and shoot the same shot with the same settings, you would have massively different exposures. Not because the f-stop changed, but because the amount of light going through the lens changed. Do we need to “note” that less light is coming through by displaying a different f stop than what is actually being used? Nope, that still hasn’t changed. Now, if we were talking about T-stops, that would be different, because those are actually measuring light transmission. But as I stated in the video, the cameras with which this product could be used don’t display T-stops. So, it isn’t applicable to this situation. I know that most people already understand all this, it’s just that words mean things.
@@JustinMyersPhoto Perhaps you haven't noticed Viltrox only recently in the past few years started referring to their Focal Reducers as Speedboosters. Like I said marketing. Most people just called them boosters so they basically said screw it and conceded. BTW great video, I'm merely making the statement that there is no other way for a camera manufacturer to display the extra stop to us end users. And it's not just Canon lol. In your video you keep saying you don't like the way Canon accounts for the extra light by way of f/stop. ALL the camera manufactures account for it the exact same way, I'm not understanding how you are zeroing in on Canon. Since a reducer changes the effective focal length, this changes the f or t-stop. t or f, makes VERY little difference and are essentially the same thing. Yes we get one is slightly more scientifically accurate, but for the sake of just merely getting a proper exposure for an end-user, its the same thing. So yes the reduction of focal length changes the f-stop. You can find this data on any write-up online regarding why the extra stop is accounted for in an additional F or T stop of light. I understand that sometimes once we find out about the difference between T and F we get all biased against "those F-stoppers" lol those dam Fstop people not measuring light accurately. It's the same dam thing and you know it. You'd need a light meter to actually measure the difference in the two and I'd argue that in most cases it wouldn't be the difference between a properly exposed frame, or an under/over exposed one. I'm sure we'll go our separate ways and be successful, and I totally understand what you mean when you're making the point that the iris is not physically widening. All I believe happened, imo, is the engineers had 3 ways to program the camera's software to show you as an end user that "hey there is one more stop of light we're detecting here." They could've used the Shutter/ISO/ or Iris. Since we have 1 extra stop of light hitting the sensor, if all 3 methods of reading our exposure do not change and its the same readout as if there was no reducer, then all of your images would be one stop over. Literally the only way for the software to alert you that the image is 1 stop brighter is to account for it within the lens and camera software by way of Iris. I think the engineers just expected end users to have the common sense to realize that it's physically impossible to widen out metal blades within a fixed housing, by merely adding an adapter.
@@STGFilmmakers F-stops and T-stops are not at all the same thing. They don’t measure the same thing and they are not at all equivalent. I’ll try this for you again. F-stop is the size of the aperture opening in relation to the focal length of the lens. It does not measure the amount of light that comes through the lens. It *affects* the amount of light that comes through the lens. However, the amount of light that is transmitted through a lens at any given f-stop can and does vary greatly across lenses. For a dramatic example take Canon’s two RF 85mm f1.2L lenses. At the same f-stop, the base version allows multiple stops more light through the lens than the DS version. Same focal length, same mechanics, same manufacturer, same F-stop, but massively different light transmission. For a less dramatic example, take the Canon RF 35mm f1.8 and RF 85mm f2. I’ve tested the lenses side by side and in that video, you can see that this 85mm consistently allows over 1/3 stop less light through the lens than the 35mm at the same F-stop. Why? Because F-stop doesn’t measure light transmission. That’s the entire reason why T-stops were created. Using T-stop and F-stop for getting exposure is not at all the same thing. Now, if you wanted to make the argument that as a “focal reducer” it is creating a new optic, and thus changes the focal length of the lens, then yes it would be a different F-stop value. As I’ve explained several times in this video and comments, a focal length change does *not* get noted in Canon’s photo cameras (the C70 being a cine cam is the only exception on the RF mount currently). As I and most people who reviewed this product stated: it probably didn’t make sense at the time to get this Viltrox product for the C70 and didn’t make sense to get the Canon product for a mirrorless camera. That led to the confusion wherein several RUclipsrs had encouraged people to get this speedbooster (call it marketing if that makes you feel better, but that’s the name of the product) and that their 50mm f1.4 lens would now be a *50mm f1.0 lens that they can shoot in APS-C mode. As I stated in the video, this is an issue created by RUclipsrs not understanding optics, but again, the way that Canon displays the changes led to that misunderstanding.
Idk why you make such a big deal about people talking about f stop conversations. The fact is that yes jt delivers more light from the normal equivalent maximum if the lens. That needs to be reflected somehow and its not going to be shutter speed or iso. So obviously its the apature. Also you do effectively get more dop from a speedbooster. Not because of the light on the sensor or lens but because you remove the punch in and can get closere to your subject while still showing the background. DOP = DISTANCE not apature and yes the speedbooster directly effects distance and framing
So, several things to realize here: Firstly, a brighter exposure does not automatically mean a change in aperture. If you turn the lights up to twice the output, the exposure is a full stop brighter, but that doesn’t equate to a different aperture. Secondly, at the time of this video, there were no APS-C sensored RF mount cameras. People were saying that you would get more DoF (not DOP, that’s Canadian for director of photography / cinematographer) due to the confusing display of a different f-stop. But they were comparing the idea of shooting full frame without a speedbooster, to shooting in an APS-C crop with the speedbooster on the same camera. That would not change your framing, and therefore does not change DoF, as I showed in the video. Now that we have RF mount cameras with natively APS-C sensors, it is a different story, wherein using a speedbooster can affect your framing. However, saying that aperture doesn’t affect DoF, is inaccurate.
F-stops don't directly refer to the iris size but the ratio of the focal length to the entrance aperture. eg. 50mm f/1.4 has an entrance pupil of 50mm÷1.4=⌀35mm.
By changing the focal length, the F-ratio will also change. eg. 50mm f/1.4 & 0.71x, the entrance pupil remains ⌀35mm while the focal length becomes 35mm. N=(50mm×0.71)÷⌀35mm=f/1.0
Yes, if you are considering the addition of the speed booster to form a new optic at a different focal length. I’m referring to people who have said a 50mm lens with speed booster taken in APS-C crop will have a shallower depth of field than using that same lens without the speed booster with the full width of the sensor, assuming a wide open aperture in both instances
If one were to compose the same portrait using the same lens with and without the speed booster on a crop sensor, and if the portrait were to remain constant, the photographer will need to move closer when using the speed booster. The net result is a more blurry depth of field. So while you are correct, technically, people tend to make assessments, not on technicalities but on compositions, so all compositions being equal one will get more bokeh with the same lens,
Well, first I would point out that distance to subject is also a technicality.
But this video is several months old and at the time there were no APS-C sensor cameras on the RF mount. That is why I specifically reference comparisons between shooting full frame without the speed booster and in a cropped sensor mode with the speed booster
yes and no...
f-stop measures the amount of light able to pass through the lens. t- stop is the amount of light that comes out the other side. a speedbooster squeezes more light into the area of the lens that will hit the sesnor. canon is justified in doing what they do. it pretty much does make your lens faster. this is also why the background blur changes.
Yes and no…
F-stop is a ratio of the size of the opening of the aperture to the focal length. It does not measure light. It does affect the potential of how much light can pass through the lens.
A speed booster doesn’t not do anything “into” the lens. It concentrates light that comes *out* of the lens.
If you want to think about your 50mm lens + speedbooster as now being a new, different 35mm lens, then yes, it would be faster than an equivalent 35mm lens.
However, the background blur does not change. A 50mm f1.4 lens shot wide open on the full sensor width, without speed booster, has the exact same depth of field and background blur that you get from that same lens wide open with a speed booster using an APS-C crop. The background blur does not change.
This is the confusion I’m trying to clear up
@@JustinMyersPhoto correct
@@JustinMyersPhoto Canon isn't the problem. It's RUclipsrs who don't understand F-stop and crop equivalence.
An EF 50mm F1.8 with this speedbooster will indeed give you the same image (same bokeh and light gathering) as a theoretical EF-S 35mm F1.26, so why should the display read anything else?
The problem is when people compare between crop and FF. They forget that the 50mm F1.8 on a crop sensor (without a speedbooster) gives the image equivalent of 80mm F3 on a FF. Forgetting that 1.6x makes 0.71x look powerful...
@@masina9447 yes, see that’s the thing: their cameras don’t display equivalence. A 35mm EF-S lens, is a 35mm focal length regardless of the sensor it is put in front of. Using a 35mm EF-S lens would yield the same field of view on a full frame sensor as a 35mm EF lens. The only difference being that the edges of the sensor would be dark since the EF-S lenses are designed to project onto a full frame sensor. And despite both a 35mm EF and a 35mm EF-S lens on an APS-C sensor giving a full frame equivalent field of view to a 56mm, they are both still displayed on the APS-C camera as 35mm, because the sensor size doesn’t change the focal length.
Canon treats speed boosters and extenders as creating a new optic when paired with a lens, which is fine, but like I said it causes confusion on the topic of focal length and sensor size, where there is already rampant confusion.
@@JustinMyersPhoto Let's put it this way, a 50mm/1.4 + speedboodter is having a DoF of a "35mm/1.0" which is more or less equal to DoF of a 50mm/1.4.
Regarding your comments about speedbooster & optics/F-number. (I never heard of this optic for cameras.) F-number is NOT the aperture; it is the RATIO of focal length to aperture diameter. The reason this is important is that any lens with any focal length will give the SAME light intensities at the sensor viewing the same scene. You need know ONLY the F-number to set exposure. (There is math I can go into if your interested how this works.) The focal length sets the SIZE of the image when viewing a given scene; size is proportional to focal length. Now you introduce optic in the path that reduces the size (since you say brightness goes up by 1 F-stop, the size must by reduced by the square root of 2, or about 0.7). What has happened is that the effective focal length of the lens/booster combination has been reduced by the same ratio. So if you were using 50mm lens, with the booster it becomes about 35mm lens ("wider angle" in that image is smaller, but cropped to the same angle of view). The aperture has not changed, so the F-number HAS been reduced by that same factor. So I allege the statement made by Cannon about F-number is CORRECT, because that RATIO changed. If you using an old-fashioned light meter & using camera in manual mode, you would adjust the wheel on the meter to the F-number 1 stop faster to read out the proper exposure time. In essence, the F-numbers on the lens setting ring are all reduced by 0,7.
I assume you are familiar with "teleconverters" that photographers & astronomers use, to crank up magnification. These INCREASE F-number (you must up your exposure time to get photo). They are used when light is available & you don't want heavy, expensive "long" lens. What this thing does is the opposite. Couldn't you use a "shorter", wide-angle lens instead? (Perhaps it is because that lens, being able to expose the full frame, is more expensive?)
I understand where you’re coming from, but you’re confused on a few points.
The F-number is a ratio of the size of the aperture to the focal length of the lens. The size of the sensor does not affect either of those. For instance, if you were to put a full frame lens on an APS-C camera, it would not change the maximum aperture. What you’re getting confused with is “equivalent aperture” which is just an attempt to help shooters have a frame of reference between sensor sizes.
As far as F-number allowing you to dial in exact exposure, that’s just a misunderstanding. As I said in the video, as well as what you already said in your comment, f-stops measure aperture size to focal length, not light transmission. And again as I pointed out in the video, there are a lot more factors involved in actual light transmission and, thus, exposure. Lens elements, lens coatings and more can affect light transmission. For an extreme instance of this, look at the Canon RF 85mm f1.2L vs Canon RF 85mm f1.2L DS lens. The exact same f-stop gives about a 2 stop exposure difference between the lenses. I understand where your confusion comes from with light meters, but those are not made to get you exact exposure. They were designed to get you as close as possible in a time where you couldn’t see your exposure until you got back to the dark room.
You’re similarly confused with what you’re supposing about focal length. Focal length is, again, an optical measurement and has nothing to do with the size of the sensor. Putting a 24mm full frame lens on an APS-C camera does not change the focal length. I understand that, again, people often refer to “equivalents” between sensor sizes, but, again, that is just a reference point for similar field of view. Different focal lengths have different aesthetic characteristics based on their focal lengths, that doesn’t change with the size of the sensor. The sensor just records different portions of that.
I understand that it’s confusing, hope that helps 👍
@@JustinMyersPhoto I understand the sensor has nothing to do with the light intensity delivered by the lens (whether some of it misses the sensor or not). Regarding F-number, I also understand the "T-number" as F-number fudged upward by light loss factor (this is usually negligible on modern expensive lenses except the most exotic).
I am not confused about focal length! Focal length & distance alone determines the size of the image, period, whether sensor is there or not. When you point a lens at a scene, focal length alone determines the area into which the light is delivered. I never declared that installing a lens on a different camera changed focal length!
But when you introduce another optic between the lens & the sensor, that optic becomes part of the lens & ALTERS its characteristics. Specifically, the speed booster reduces the focal length of the combination. Try the following experiment. Put 50mm lens + 1 stop speed booster on camera, put on tripod & photograph scene. Repeat this putting 35mm lens on & photograph same scene again. (Make both photographs full-frame, do not crop.) I allege the objects in the photos will be the SAME SIZE. You will be able to overlay the 2 photos & match them up in the central area. The only difference will be the dark border on the photograph taken with the speed booster. If the F-stop of the 35mm lens were set 1 stop faster than that of the 50mm lens, the brightness of the 2 images will also match in the central area.
@@bpark10001 okay, I see where you’re coming from, presuming that a speed booster attached to a lens becomes part of the optic, rather than a post-optic modification.
So, where you’re coming from, you’re not looking at it as a comparison of the full frame image of one lens, to the APS-C image of the same lens + speed booster, which is where the confusion has been online. Which has been centered around depth of field gained/losses with a speed booster in APS-C vs the same lens on full frame without the adapter. People have thought that using the speed booster + 50mm at max aperture in APS-C mode would give them a shallower depth of field than using that same 50mm at max aperture without the speed booster using the full sensor width, which isn’t the case.
I don’t take issue with anything you are saying. I think we’re just talking about it differently. Definitely appreciate the input 👍
@@JustinMyersPhoto Regarding depth-of-field, reducing focal length increases it, & decreasing F-number decreases it. I would expect there to be little change as the 2 effects would tend to cancel.
Regarding the comparison I advocated making, it would be neat for you to set up & publish the 2 photos. I suspect it would do much for educating the public, more so than just explaining. If you include foreground & background objects, some well lit & others not, & do same exposure on both, we could see the depth-of-field & F-number effects.
@@bpark10001 I actually did test it. You can see some of the side by side clips in the video section. Like I said, the confusion I was addressing involved depth of field with a lens used on full sensor width without speed booster vs depth of field with the same lens in APS-C crop using the speed booster. There is no change in depth of field there.
I do agree, a video about the test specifically would be interesting, but I would hesitate to do it with photos. I feel like that might add to the confusion where people might think it could be useful for photography. Again, they would be getting the same image as using the lens without the speed booster on the full sensor width, except that the image is then only projected onto the center, APS-C size of the sensor. All they would be doing is reducing the resolution of the image at that point
Hey Justin, thanks for this. I really appreciate your clear explanations and, I share your frustration that some reviewers just get it wrong with the facts on what a booster physically can and can't do. I think I'll get a viltrox .71x for my RP@4K25p, and in recent videos I have been using this camera for detail work with manual focus, so AF issues not an issue. I use the R6@4K50 with EF 17-40 for FF footage with me talking so that's where the AF is critical. (Will probably get a RF16/2.8 soon too).
The one problem I have observed with the RP in 4K mode is rolling shutter. It can be avoided by using exposure 1/200 or faster, which is okay for most of my work, but then with fast movement it can appear like a series of stills rather than a video with movement.
Anyway thanks again for your insight and clarity. If you ever get a bonsai I hope I can repay you the favour !! 😁
Hey, glad you enjoyed it! That is another thing I forgot to mention about the 4K on the RP, the terrible rolling shutter performance. But if you understand what you’re going to get and have a workaround that suits you, the speed booster is interesting at this price
have this exact same speedbooster, Viltrox Ef-R3 and I have autofocus issues when a subject is not close to the lense and I'm on 24mm, when i zoom in to 70mm the autofocus starts working...I have it paired with EOS R
I can't tell you how many arguments I got into out here on the internet about this very thing. All one has to do it shoot the same subject (same distance, same parameters) wide open without a speed booster and then shoot the same lens wide open with a booster and then compare the photos. I always tell people bokeh and depth of field are are driven by lens characteristics, and these things have zero/nothing to do with sensor size.
Wow thanks for the clarifications...
Shooting in 4k 60p in crop mode on the R6 with the speedbooster was a really interesting test, thank you for that! I think that would appeal to people in the wedding industry that are nervous about the overheating in FF 4k 60p, but want the "FF Look" still.
Ya, it could definitely be useful for people who need long takes in 4K60
Hey can you tell me what grip or L bracket you were using with the arca Swiss plate on both vertical and horizontal do r the EOS r Body been looking for one that at least covers the whole body when adding the bracket
Yes, it’s the SmallRig L bracket: ruclips.net/video/JRoJ9FAIHyo/видео.htmlsi=_gdAjCLCspHSWd4D
Nice job as usual Justin. I wasn’t aware that the 4k crop mode didn’t overheat as easily. This video was very helpful. I’ll be using this to my advantage doing weddings… pretty much my primary case scenario where I see the overheating warnings on my R6.
Glad you found it helpful. Ya, the crop mode uses a lot less of the sensor and a lot less processing, so things heat up a lot less
@Just Esmond are you using primarily EF lenses adapted on the R6?
@@JustinMyersPhoto I’m 50/50 with RF glass. I have the RF 35, 50, Samyang 85 and 24-105 f4 L. In terms of EF glass I have the EF 17-35 L, 24-70 L, 50 f1.4, and 100 mm L macro. I rent the 70-200 when needed (rarely). So I use both EF and RF glass as needed. I love the RF 35 for video. It’s on my R6 50-60% of the time for video. Also use an RP for video as a B cam.
I’m gonna test out the crop mode this week using my existing glass to test out the overheating issue in crop mode. I’ve got range from 17 to 105mm with the glass I have so I’m flexible and none of my pieces are throwaway lenses.
@@justesmond gotcha, ya that’s a nice, well-rounded set of lenses. Hopefully the crop mode will be helpful for you 👍
thanks for the video Justin. So now with the R7 in play, would you recommend getting a speedbooster to give that full frame feel for photography? I know its not affecting the aperture still but the light and framing will be more in line with a full frame than aps-c wouldn't it?
Yes, you’re correct. I haven’t tried the R7 yet, but it should be a good option for that
Probably cant use this on r5C?
Well, you actually can, but I don’t see it being particularly useful. You would only be able to use it on the R5C when shooting in one of the sensor crop modes. There’s not a whole lot of advantages to doing that with the R5C vs just shooting with the full sensor. It wouldn’t noticeably affect framing / field of view, so I can’t think of any reason to use a speedbooster with the R5C in crop mode. Instead you can just use a regular EF-RF adapter and shoot in full sensor mode
Thanks for the video, Justin. I have one question: would you recommend a speed booster to use on a URSA Broadcast G2? Would it be a good idea to use Full Frame lenses on the Broadcast G2 with it's Super 35 sensor?
To my memory that camera has an EF mount, right? Unfortunately, there isn’t a speed booster option for EF mount cameras
Really tempted to pick one of these up mainly to use with a 1.4 lens to get insane low-light capability. I use the RF 24-70 with my R6, but occasionally use adapted EF (Sigma 24 1.4, EF 16-35, etc.). I might go with the PRO version of the EF-RF just for the security of that locking collar when using the combo on a gimbal.
Awesome, so what type of video do you typically shoot?
@@JustinMyersPhoto 80% weddings, 20% commercial right now. Do you have any low light examples of the adapter with the R6?
@@jej3films okay cool. No, I don’t really have any lowlight examples. My primary use case was to match the full frame image in a crop sensor mode. I didn’t really test it for lowlight, but it literally just gives an extra stop of light. So, whatever ISO you’re at wide open, you would shoot half that ISO value to get the same exposure wide open with the speed booster
While not the same, I have the EF to EF-M Viltrox speed booster. I use it with my 24-105 f4L for video (and photos) with very nice results. Not as good as that lens on my RP but not much worse either (I really can't tell most of the time). I don't have an R5 or R6 to compare with, but I am looking at the R6 in the near future. I've noticed that my M50 also reports the lens/speed booster aperture at f2.8 not the f4.0 of the lens. I wonder if Canon is programming their cameras to show "favorable" apertures when using image modifying attachments, as I see that my macro lense doesn't seem to record aperture properly at high magnification with extension tubes (at 1-2x life size f2.8 on camera should be about f5.6 if I remember the calculations from the film days where you had to overide exposure settings when using bellows or tubes), hmmm.
Nice! I never owned an M series camera, so didn’t get to try any of the speed booster options for that.
Ya, as far as displaying the aperture correctly/incorrectly with any type of modification attachment, I think it’s just a misguided attempt at when and what to change in displays. Can’t speak for sure about extension tubes, because I don’t use them, but the speed booster thing is definitely their attempt to tell the user that the exposure is brighter. But it doesn’t make sense to do it that way and it has caused a lot of confusion unfortunately
None available for sale. Apparently no longer on the market. Does anyone know why?
Canon made third party lens and accessory manufactures stop selling RF mount products a while ago, this was one of the casualties
@@JustinMyersPhoto Wasn't that just about RF with autofocus? Couldn't we have a booster with no electronics?
@@rangersmith4652 it is technically possible, yes. Probably not a large market for it though
@@JustinMyersPhoto I'd buy it tomorrow.
@@rangersmith4652 reach out to them, you never know
the connection of the speed booster is straight wires inside , therefore wont need any firmware .
Not sure about your definition on f-stop. I think you may be get Aperture, f-stop and t-stop mixed.
No, I could have probably explained it better
thx for the video mate = )
👍
I'm a bit lost when you say it doesn't make sense for photography. I'm thinking of getting a crop sensor camera and using this to get back the focal length of my FF lenses. Doesn't that make sense?
If you are looking specifically at the R7 or R10, it definitely does make sense. Those are the only two crop sensor photo cameras from Canon with the RF mount. When I made this video, there were only full frame RF mount photo cameras, that’s why I said that it didn’t make sense at the time. Now with the R7 and R10, this style of speed booster does become much more interesting
@@JustinMyersPhoto I see, thanks for that. I'm just wondering about the sharpness now.
@@ArcanePath360 I haven’t used the APS-C RF mount cameras yet, so I don’t have a way to accurately test sharpness on images more than about 13 MP, but I didn’t see any dramatic loss in sharpness from the speed booster
@@JustinMyersPhoto Okay, thanks. Everybody still waiting on that R7 to get released properly. In the UK it's hit waiting list and hope. But we'll be lucky to get our hands on it this side of summer
@@ArcanePath360 ya, is the R7 what you’re getting?
It's not Canon cameras. My Panasonic Lumix GH5s did the exact same thing by displaying the "adjusted" f-stop. I think everyone knows what it is doing, it's just easier to say that it gives you a 1 stop gain in light.
Fair enough. I have still seen a lot of confusion around how it affects bokeh primarily, which is what I was hoping to address
Metabones has one also, and it supports all the r series cameras.
Yes, I mentioned it somewhere in the video. It’s about 2x the price of this one though, so I definitely can’t recommend it at this point unless someone already has it. Do you shoot with it?
@@JustinMyersPhoto yes I have the metabones one.
I got it when I had the eosr and it works great.
Metabones is very good with keeping the firmware up to date.
I haven’t had any issues with color as you mentioned you had with the viltrox.
I did a lot of research on Viltrox speed boosters when I was thinking of getting one for the m6 mkii camera I have.
As you say the Viltrox price made it a intriguing option vs the metabones which is for the m series cameras much more expensive than the Viltrox.
As I did my research and dug deeper I found reviews saying not to get the Viltrox as the quality veries greatly from unit to unit and the image quality is not on the level of the metabones.
The metabones cost 479.00 so as you say the Viltrox is cheaper, but you also have to ask yourself why is it cheaper?
I tried both speed boosters on my m6 mkii and the metabones was noticeably better in build quality and image quality.
479.00 seems to be metabones price as my speed booster for the eosr camera was that price too.
I agree though if you don’t mind a image quality hit and possible quality issues, the Viltrox is the answer.
But if you want the best possible image quality and excellent build quality then the metabones is definitely the better choice.
I haven’t tried Viltrox speed booster for the r series cameras so maybe they are different now.
This is my opinion of coarse based on the research I did, others may feel differently.
Excellent video as always Justin.
@@wadesweeney2200 ya, when the metabones came out back then, it was the obvious choice, because it was the only choice. Now, it’s the same price as the first party Canon speedbooster. It does have very good image quality, but it’s about the same as the Viltrox and neither are quite as good as the Canon version.
I definitely don’t think this Viltrox RF speedbooster is a “hit” in image quality compared to the metabones. The price difference is pretty clearly based on the electronics being copied from the Canon speedbooster, so they don’t have the R&D costs that Canon and metabones had.
Like I said, at the time when you got it with the R, metabones was the only choice. Now, the Canon version is definitely the highest quality option, although they are all three pretty close.
If someone is getting a third party RF speedbooster now though, it’s kind of hard to suggest paying double the price. I’d say to go Canon brand now if they are willing to pay that price
Thanks for watching the content!
I have never overheated with either of my r6's in 4k all day so I am surprised to still hear that people have that issue. Interesting video as well here, I didn't now they made a speed booster for these cameras. I just use the EF to RF adapter with no glass. Both the Canon and Vello are great.
Ya, as I mentioned, I’ve never had an issue with the R6 overheating during my actual use.
As I said, the speed booster was developed for the C70, it just works with the mirrorless cameras as well, seeing as they use the same mount.
The speed booster would only be for using the crop video modes of the mirrorless cameras, as I mentioned in the video
Definitely not my testimony. I frequently have the overheating warning during weddings. Just having the R6 on during the day creates overheating issues for me.
@@justesmond ya, it definitely can overheat, and depends on how you shoot as well
@@justesmond dang, I run two at wedding and never had an issue luckily. Hopefully they don’t cause you too many issues in the future. Maybe they’ll bring out a firmware update to fix it or battle it at least.
@@DLivingston The crazy thing is my camera is up to date with the latest firmware so it should not be having those issues. But I am in south FL and heat and humidity are a part of my everyday environment. I’ve had to take out the battery from time to time when not shooting to allow the camera to cool.
It just creates a worry that I’d rather not have to think about at all on a wedding shoot. And turning the camera on and off could make me miss something important. So this crop mode discussion that’s the topic of this video is definitely on my radar to try to see if I can record without worrying about overheating.
Canon really shoot themselves in the foot with their greedy pricing. Just waiting for a 3rd party battery grip to come out of the R6 that isn't a ridiculous price as well now.
Thanks for explaining how the speed booster works with brightness. It makes sense now. It is misleading that it changes the f stop. It's more like increasing the ISO without the extra noise. That would have been a better description, or maybe just light intensity is increased.
我问了Viltrox 公司客服 因为知识产权佳能已经通知了Viltrox 这个转接器以后不允许卖了 以后公开市场上不会有货了
Great presention
Thanks, glad you enjoyed it! Are you using or looking into getting a speedbooster?
@@JustinMyersPhoto Not yet, however you make sound quite appealing. Currently using Canon Rp.
@@timelesstruths gotcha. Have you used the 4K on the RP very much?
Its not a "booster" lol its a reducer. Im just sayin. Speedbooster is simply the branded name Metabones gave to their focal reducers. But its not a Viltrox Speedbooster. It's a Focal Reducer. I understand most people probably understand this, it's just that words mean things :P In addition, to that, ALL other manufacturers account for this extra light the same way. By applying it to the iris. There is no other way to account for it. It's only done this way for the end user to get a proper exposure. Accounting for it by way of Shutter speed makes no sense because it would affect your motion blur and accounting for it by way of ISO makes no sense because ideally you'd like to shoot at the cameras native ISO. The ONLY other option is to account for it by way of Iris, because since the reducer isnt physically opening the iris wider (as you stated), it's not effecting your image visually, while the two other methods of accounting would.
Wow, it’s hard to get so many things wrong in one comment, but I’ll try to help you figure things out lol.
Viltrox’s products are, in fact, called speed boosters by Viltrox and are marketed and labeled as such on their website. A quick Google search could have saved you that embarrassment. Just saying.
Also, your argument behind why iris is the way that a difference in exposure should be noted, is actually exactly why it doesn’t make sense to change the displayed f stop. As you stated: “since the *speedbooster* isn’t physically opening the Iris wider, it isn’t *affecting* your image visually”. Opening the iris wider would, in fact, affect your image visually, which is exactly the problem with changing the displayed f stop when the Iris opening is not being changed. As I explained in the video, f stop is a measurement of how wide the aperture is opened in relation to the focal length of the lens.
A change in light transmission through the lens does not, in and of itself, need to be noted by shutter speed, ISO, and/or f-stop. If you shoot an image outside in broad daylight with no extra lighting, and then come back at night and shoot the same shot with the same settings, you would have massively different exposures. Not because the f-stop changed, but because the amount of light going through the lens changed. Do we need to “note” that less light is coming through by displaying a different f stop than what is actually being used? Nope, that still hasn’t changed.
Now, if we were talking about T-stops, that would be different, because those are actually measuring light transmission. But as I stated in the video, the cameras with which this product could be used don’t display T-stops. So, it isn’t applicable to this situation.
I know that most people already understand all this, it’s just that words mean things.
@@JustinMyersPhoto Perhaps you haven't noticed Viltrox only recently in the past few years started referring to their Focal Reducers as Speedboosters. Like I said marketing. Most people just called them boosters so they basically said screw it and conceded.
BTW great video, I'm merely making the statement that there is no other way for a camera manufacturer to display the extra stop to us end users. And it's not just Canon lol. In your video you keep saying you don't like the way Canon accounts for the extra light by way of f/stop. ALL the camera manufactures account for it the exact same way, I'm not understanding how you are zeroing in on Canon. Since a reducer changes the effective focal length, this changes the f or t-stop. t or f, makes VERY little difference and are essentially the same thing. Yes we get one is slightly more scientifically accurate, but for the sake of just merely getting a proper exposure for an end-user, its the same thing.
So yes the reduction of focal length changes the f-stop. You can find this data on any write-up online regarding why the extra stop is accounted for in an additional F or T stop of light. I understand that sometimes once we find out about the difference between T and F we get all biased against "those F-stoppers" lol those dam Fstop people not measuring light accurately. It's the same dam thing and you know it. You'd need a light meter to actually measure the difference in the two and I'd argue that in most cases it wouldn't be the difference between a properly exposed frame, or an under/over exposed one.
I'm sure we'll go our separate ways and be successful, and I totally understand what you mean when you're making the point that the iris is not physically widening. All I believe happened, imo, is the engineers had 3 ways to program the camera's software to show you as an end user that "hey there is one more stop of light we're detecting here." They could've used the Shutter/ISO/ or Iris. Since we have 1 extra stop of light hitting the sensor, if all 3 methods of reading our exposure do not change and its the same readout as if there was no reducer, then all of your images would be one stop over. Literally the only way for the software to alert you that the image is 1 stop brighter is to account for it within the lens and camera software by way of Iris. I think the engineers just expected end users to have the common sense to realize that it's physically impossible to widen out metal blades within a fixed housing, by merely adding an adapter.
@@STGFilmmakers F-stops and T-stops are not at all the same thing. They don’t measure the same thing and they are not at all equivalent.
I’ll try this for you again. F-stop is the size of the aperture opening in relation to the focal length of the lens. It does not measure the amount of light that comes through the lens. It *affects* the amount of light that comes through the lens. However, the amount of light that is transmitted through a lens at any given f-stop can and does vary greatly across lenses. For a dramatic example take Canon’s two RF 85mm f1.2L lenses. At the same f-stop, the base version allows multiple stops more light through the lens than the DS version. Same focal length, same mechanics, same manufacturer, same F-stop, but massively different light transmission. For a less dramatic example, take the Canon RF 35mm f1.8 and RF 85mm f2. I’ve tested the lenses side by side and in that video, you can see that this 85mm consistently allows over 1/3 stop less light through the lens than the 35mm at the same F-stop. Why? Because F-stop doesn’t measure light transmission. That’s the entire reason why T-stops were created.
Using T-stop and F-stop for getting exposure is not at all the same thing.
Now, if you wanted to make the argument that as a “focal reducer” it is creating a new optic, and thus changes the focal length of the lens, then yes it would be a different F-stop value. As I’ve explained several times in this video and comments, a focal length change does *not* get noted in Canon’s photo cameras (the C70 being a cine cam is the only exception on the RF mount currently). As I and most people who reviewed this product stated: it probably didn’t make sense at the time to get this Viltrox product for the C70 and didn’t make sense to get the Canon product for a mirrorless camera. That led to the confusion wherein several RUclipsrs had encouraged people to get this speedbooster (call it marketing if that makes you feel better, but that’s the name of the product) and that their 50mm f1.4 lens would now be a *50mm f1.0 lens that they can shoot in APS-C mode. As I stated in the video, this is an issue created by RUclipsrs not understanding optics, but again, the way that Canon displays the changes led to that misunderstanding.
@@JustinMyersPhoto 👍
Idk why you make such a big deal about people talking about f stop conversations. The fact is that yes jt delivers more light from the normal equivalent maximum if the lens. That needs to be reflected somehow and its not going to be shutter speed or iso. So obviously its the apature. Also you do effectively get more dop from a speedbooster. Not because of the light on the sensor or lens but because you remove the punch in and can get closere to your subject while still showing the background. DOP = DISTANCE not apature and yes the speedbooster directly effects distance and framing
So, several things to realize here:
Firstly, a brighter exposure does not automatically mean a change in aperture. If you turn the lights up to twice the output, the exposure is a full stop brighter, but that doesn’t equate to a different aperture.
Secondly, at the time of this video, there were no APS-C sensored RF mount cameras. People were saying that you would get more DoF (not DOP, that’s Canadian for director of photography / cinematographer) due to the confusing display of a different f-stop. But they were comparing the idea of shooting full frame without a speedbooster, to shooting in an APS-C crop with the speedbooster on the same camera. That would not change your framing, and therefore does not change DoF, as I showed in the video.
Now that we have RF mount cameras with natively APS-C sensors, it is a different story, wherein using a speedbooster can affect your framing.
However, saying that aperture doesn’t affect DoF, is inaccurate.
your funny but nice try and no or even focal reduced to a nah
I’m not sure what you’re trying to say, but thanks for stopping by