I love how that this isn’t a channel for attention, it’s a channel for the science. Thank you Ben, been watching for years. Also thanks for helping out the other tubers.
I don't remember HOW I came across this site years back, but I'm so glad I did, it's the most wonderful oasis of experimentation, testing, education and skill. Don't change Ben, you inspire me constantly and I know you inspire many others :) All the best from the UK
i dont remember either, but im pretty sure it was something related to the DIY electron microscope stuff. dude post videos that sound like clickbait but are literally just what the title says.
I wish i had the ability to give you all the money you need to explore any, and every, idea that interests you. You approach topics at a higher level than most, while also effectively communicating the topic to those of us with the base knowledge. Love your videos!
You mention that the focal distance was huge and that if you focused the lens on something a foot away, the objects at the far end of your shop was still in focus. This seems like the holy grail to me! What I have been struggling to find a solution for. Being a competitive iron sight pistol shooter I need to focus on the front sight but at the same time see the target as sharp as possible. With age I have begun to struggle with this and have seen multiple optometrists and tried different lenses, irises etc. Nothing really works. The lenses help with being able to focus on the front sight but the target gets much blurrier. Would it be possible to adapt your findings to a lens-system that could be mounted in front of my eye? It's a long shot that you will read this but I really hope you will. Thank you so much for your videos!
I bet Huygens Optics could clarify some stuff for you, he makes ground glass lenses for fun. 14:04 I don't understand the math, but it sounds like you're saying the plane of focus isn't flat (field curvature) so the numbers are all fucky and don't work out the way they ideally should.
Glass also has its own refraction index... He can try, but drilling into glass, getting oil in there and getting air out seems like too much effort (and even lower yield) for something that most likely won't work that well.
What's the effectiveness of the infrared filter? Having used NVG's, your camera looked like perhaps it was still capturing more infrared light giving the impression that it was brighter.
@2:04 made me say OMG out loud because that one microscope I bought off eBay must've needed oil. I just crashed the lens into the slide every time I used it... for months... (not every day)
I'm no optics expert, but I'm starting to suspect there's some circular reasoning going on. NA is a very subjective number, sine of the maximum angle light hits the sensor (at the center of the image field, for on-axis incoming rays). F-number? Clear aperture can be measured, but how do you define the focal length of an optical system with thickness? If we define it according to the diagram at 14:00 of course all make sense. But if you were to measure it, then there are optical center, field curvature, distortion and whole other cans of worms to worry about. Same thing with the fresnel lens. Is the focal length measured from its center, or its peripheral? I think the focal length lens makers put on the lens body is a mere indication of its field of view, therefore, so is the f-number.
OLD 3 TUBE red blue green big screens use cooling oil that couples the image of the tubs to the lens also There may be some use full info in such old big screens
Loved the video! Just note for your future task, that the depth of field is only related to the aperture D, and has nothing to do with the focal length f. So low F# is not really a necessity for shallow depth of field - just keep D as large as you can
Something that clicked for me a while ago vis-a-vis bokeh/DoF for a given lens, is that the f-number and its numerical relationship to the focal length are a bit of a red herring. If you're only looking at depth-of-field and not overall light collection, for all practical purposes, the only thing you need to know is the size of the entrance pupil. Hence, wide focal lengths with fast apertures have a deeper depth-of-field, since even at a low f-number you're looking at a fairly small pupil diameter. For a subject at equal distance, you might observe the real-world measured DoF to be identical between, say, a 20mm f/1.0 and a 40mm f/2.0 - even if the former would give you a much brighter image and a wider field of view. The caveat to this, of course, being that your field of view (being a product of focal length and crop factor) will likely also change the way you compose your image, so in practice this isn't always apparent. Mathematically, though, the measured depth-of-field in an image should be directly related to only two things - the distance of the focal plane, and the diameter of the entrance pupil.
Makes sense we dont see oil based lenses in production since it would only add a minor improvement over one with air gaps and probably cost significantly more to make it sealed properly
Thanks again, I enjoy your content! You can get insane depth of field with a pinhole too. opposite light gathering ability though. ;-) Pinholes are fun to make too. Many fun ways to do it. Some involve fancy toys, some basic...
The other factor that affects depth-of-field is focal distance. The further away you focus the deeper the depth. A short focal length isn't ideal for shallow focus. One benefit of the fast lens is 2-3 stops down from wide open (the peak focus of most lenses) is still 2.something and still fast but infinite depth of field. Now, if you made a 50mm f0.38 lens, you would have something
I don't know what microscope objective was used as lens, but if such thing exists, a plan achromatic immersion objective with infinity correction should be a very good option.
I am surprised that you didn't mention that you are using the lens backwards. Normally, the light goes from the slide through the oil to the eye, camera or whatever. Here you've got the light coming from where the image would normally be projected. Is the behaviour of a lens like this commutative?
Great video! Watching you play with the white card, when bowed, more of the image was in focus. Think of lenses, spherical aberration and sensors, why hasn’t someone made dome/dish shaped digital sensors?? Yeah, film would be tricky because the converted flat image would be some kind of Mercator looking projection, but digital should be plausible if the silicone can be made. Seems like an easy way to solve the round -> flat issue between lenses and sensors. Eyes do it. 🤓
Could you possibly add the books you dug into in the video description if it's not too much trouble? Am curious on the topic as well. Sidenote, found the whole video, especially the explanation part interesting. Lenses are one of those weird ares of mechanicals where it's both known and a bit of unknown with a LOT of "esoteric" stuff crammed in by hookie spookie people who try to mystify the whole thing needlessly. So it's nice whenever someone puts actual math on the table.
Are there reasons to decouple the final optical element from the sensor other than swappable lenses? Is there a cell phone camera with a bonded final optical element?
I wonder how bright this would make analog night vision. imagine a gen3+ tube with one of these bad boys. One of the big problems with night vision is the depth of field. Soldiers need to be able to read maps and fight, and switching between the two manually is a pain. If theres a deep enough focal length where everything is in focus thatd be huge.
Speaking of simple questions. Though this is probably answered somewhere online. But why does the focal length impact light gathering? On the surface Id think only the appature size matters? How is light that enters ending up impacting the image media less just because the focal length is different?
In that case, i wonder if planar fresnel exist. Neat! Also, wouldn't it be cool if now that we have mirrorless cameras, they had a full block of glass that extended to the lens and you added a little oil? Lol
[Edit: I thought the lens was made from oil with materials that refocus light all wrapped up in silica or plastic] This is probably as close as I will see to my polypropylene morphing eye lens and concave image sensor.
Come to think of it - why hasn't anybody tried to build a non-flat, e.g. concave image sensor? Wouldn't that make the required lens systes way simpler and remove most spheric effects?
Woohoo I'm early wonder what f you could get from a extra large frenel lens... i got 1 that is about 3 feet across, i got a bigger one but it's currently inside an old projection tv, that 1 was flat out made to display images....now granted those were in 480i maybe 480p but still!
If you had a bunch of sensors, then you could've put one in the oven (to its accepted temp) and then quickly done the glass removal (with the glue to glass method) by clamping the part you glued into a vise and pulled the chip up. Just a thought. This would always result in the broken pieces of glass falling down, and away from the sensor. Just a thought. This is how i delid cpus. I never do it upwards, because i'm too chikensh!t to potentially ruin it by something dropping inside.
Fascinating. I’m trying to wrap my head around refraction behavior, intuitively expecting wavelength dependent blur closer to the edge (rendering it useless for non-monochrome imagery) but apparently that is not happening 🤔
Interesting. So this means that the convention of f-number is u clear. NA is quite easy to understand, since it's just half the opening angle at wafer/sensor/film. But the focal distance is the distance of your wafer/sensor/film to Something™. I find it a bit strange to define this hypothetical plane as curved. Of course in a perfect lens, your wavefront is spherical, so it makes sense to define a curved plane. But in my opinion, the diameter of an opening pupil should not be defined as curved. For example let's say we have a sphere of radius 1 meter. Then you'd assume that the diameter is 2 meters, right? But if I follow this f-number definition, instead you should measure the diameter along the surface and end up with a diameter of pi. Of course this is convention and we decide how we define things. But this makes me feel slightly uncomfortable. Maybe we should stop talking about f-numbers and just only use NA. I'm sure that would at least make lithographers like me happy!
Math is just an approximation of reality not reality it self. There are so many details that math ignores and a reality math formula that accounts for everything would be as long as a book.
I love how that this isn’t a channel for attention, it’s a channel for the science.
Thank you Ben, been watching for years. Also thanks for helping out the other tubers.
+1!
It might be 6am here, but dang, if an AS video drops, it's watching time!
You mean ben krasnow
5 a.m. here!
Same!
5h44 here in the Netherlands...
Same ... Poland
The only channel that I have a notification for
He posts and I excuse myself from dinner.
I don't remember HOW I came across this site years back, but I'm so glad I did, it's the most wonderful oasis of experimentation, testing, education and skill.
Don't change Ben, you inspire me constantly and I know you inspire many others :)
All the best from the UK
i dont remember either, but im pretty sure it was something related to the DIY electron microscope stuff. dude post videos that sound like clickbait but are literally just what the title says.
the principal plane being not flat makes so much sense! I hope this knowledge opens up new avenues of exploration.
In case you haven't seen it, Media Division on RUclips built an f0.3 lens (by using a diffuser sheet in the middle as a hack).
I appreciate you putting the math in there. Even applied scientists can learn from theory.
You really make optics an interesting matter. Your investigation of the formula for aperture, fascinating. Kudos!
Silence then out of the blue - a banger as usual. One of the more unique subscriptions I maintain.
I LOVE LENSES I LOVE HIGH SPEED LENSES I LOVE MICROSCOPES RAHHHH
I wish i had the ability to give you all the money you need to explore any, and every, idea that interests you. You approach topics at a higher level than most, while also effectively communicating the topic to those of us with the base knowledge. Love your videos!
Recently started working at a IOL manufacturer. It’s been a lot of fun learning about optics. This video came at a great time!
MOOOOOM!! MOM! a new Applied Science just dropped, and it's friday night too, LETS GO!!
The freaks come out at night 👍😉
Really interesting video, a nice break from normal YT slop.
You mention that the focal distance was huge and that if you focused the lens on something a foot away, the objects at the far end of your shop was still in focus.
This seems like the holy grail to me! What I have been struggling to find a solution for. Being a competitive iron sight pistol shooter I need to focus on the front sight but at the same time see the target as sharp as possible.
With age I have begun to struggle with this and have seen multiple optometrists and tried different lenses, irises etc. Nothing really works.
The lenses help with being able to focus on the front sight but the target gets much blurrier.
Would it be possible to adapt your findings to a lens-system that could be mounted in front of my eye?
It's a long shot that you will read this but I really hope you will.
Thank you so much for your videos!
I bet Huygens Optics could clarify some stuff for you, he makes ground glass lenses for fun.
14:04 I don't understand the math, but it sounds like you're saying the plane of focus isn't flat (field curvature) so the numbers are all fucky and don't work out the way they ideally should.
I love @huygensoptics channel! I was about to recommend it, I have learned so much about optics and light from him.
A classic 'It depends'.
could you have drilled a very small hole in the glass sensor cover and vacuum injected the oil?
Glass also has its own refraction index... He can try, but drilling into glass, getting oil in there and getting air out seems like too much effort (and even lower yield) for something that most likely won't work that well.
What's the effectiveness of the infrared filter? Having used NVG's, your camera looked like perhaps it was still capturing more infrared light giving the impression that it was brighter.
@2:04 made me say OMG out loud because that one microscope I bought off eBay must've needed oil. I just crashed the lens into the slide every time I used it... for months... (not every day)
Most of the immersion lenses have a spring-loaded tip to prevent the smashing and carnage
10 pm. I really should go to bed, buuuuuuuut .38 oil lens
Really fabulous work here, thanks for sharing!
Wow, what a research project! Thanks.
Here I was feeling accomplished for fixing my water heater and AS drops a video about successfully building unheard-of lens apertures. D*mn!
Brilliant as always!
It's great when you find these little niches in a hobby, and it turns out to be a rabbit hole.
Outstanding work.
I'm no optics expert, but I'm starting to suspect there's some circular reasoning going on. NA is a very subjective number, sine of the maximum angle light hits the sensor (at the center of the image field, for on-axis incoming rays). F-number? Clear aperture can be measured, but how do you define the focal length of an optical system with thickness? If we define it according to the diagram at 14:00 of course all make sense. But if you were to measure it, then there are optical center, field curvature, distortion and whole other cans of worms to worry about. Same thing with the fresnel lens. Is the focal length measured from its center, or its peripheral? I think the focal length lens makers put on the lens body is a mere indication of its field of view, therefore, so is the f-number.
Nifty as always
Good work, Looks like fun.
OLD 3 TUBE red blue green big screens use cooling oil that couples the image of the tubs to the lens also There may be some use full info in such old big screens
Just in time for a fresh out the oven Applied Science video!
Loved the video! Just note for your future task, that the depth of field is only related to the aperture D, and has nothing to do with the focal length f. So low F# is not really a necessity for shallow depth of field - just keep D as large as you can
Something that clicked for me a while ago vis-a-vis bokeh/DoF for a given lens, is that the f-number and its numerical relationship to the focal length are a bit of a red herring. If you're only looking at depth-of-field and not overall light collection, for all practical purposes, the only thing you need to know is the size of the entrance pupil. Hence, wide focal lengths with fast apertures have a deeper depth-of-field, since even at a low f-number you're looking at a fairly small pupil diameter. For a subject at equal distance, you might observe the real-world measured DoF to be identical between, say, a 20mm f/1.0 and a 40mm f/2.0 - even if the former would give you a much brighter image and a wider field of view. The caveat to this, of course, being that your field of view (being a product of focal length and crop factor) will likely also change the way you compose your image, so in practice this isn't always apparent. Mathematically, though, the measured depth-of-field in an image should be directly related to only two things - the distance of the focal plane, and the diameter of the entrance pupil.
Makes sense we dont see oil based lenses in production since it would only add a minor improvement over one with air gaps and probably cost significantly more to make it sealed properly
Yes I did find that interesting ! .. and I very much hope "next time" is in the very near future ^^
Thanks again, I enjoy your content!
You can get insane depth of field with a pinhole too. opposite light gathering ability though. ;-)
Pinholes are fun to make too. Many fun ways to do it. Some involve fancy toys, some basic...
Good luck man :) I love all ya do
The other factor that affects depth-of-field is focal distance. The further away you focus the deeper the depth. A short focal length isn't ideal for shallow focus. One benefit of the fast lens is 2-3 stops down from wide open (the peak focus of most lenses) is still 2.something and still fast but infinite depth of field. Now, if you made a 50mm f0.38 lens, you would have something
My favorite part of the video - you use "raises the question" instead of "begs..."
yes!
this is like how the big daddys see the world in bioshock
I don't know what microscope objective was used as lens, but if such thing exists, a plan achromatic immersion objective with infinity correction should be a very good option.
Fascinating
I am surprised that you didn't mention that you are using the lens backwards. Normally, the light goes from the slide through the oil to the eye, camera or whatever. Here you've got the light coming from where the image would normally be projected. Is the behaviour of a lens like this commutative?
Next step, deep dive on the infinity lens ?
Ohh yes. I've just been looking into lens making and low f number!
Great video! Watching you play with the white card, when bowed, more of the image was in focus. Think of lenses, spherical aberration and sensors, why hasn’t someone made dome/dish shaped digital sensors?? Yeah, film would be tricky because the converted flat image would be some kind of Mercator looking projection, but digital should be plausible if the silicone can be made. Seems like an easy way to solve the round -> flat issue between lenses and sensors. Eyes do it. 🤓
It would be interesting to see this lens on a Sony Starvis2 low light sensor
Could you possibly add the books you dug into in the video description if it's not too much trouble? Am curious on the topic as well.
Sidenote, found the whole video, especially the explanation part interesting. Lenses are one of those weird ares of mechanicals where it's both known and a bit of unknown with a LOT of "esoteric" stuff crammed in by hookie spookie people who try to mystify the whole thing needlessly. So it's nice whenever someone puts actual math on the table.
Hmm - does this mean you could make a really good cell phone camera by molding the final element together with the sensor?
Are there reasons to decouple the final optical element from the sensor other than swappable lenses? Is there a cell phone camera with a bonded final optical element?
The world called, it asked for you to have 100 children.
Excited for the eventual Hugens comment
0:10 Isn't f number Focal length / Aperture
That ruler! Is that ruler listed in the description? I would love to get one
It's the Digikey PCB ruler - can't post a link but search for DKS-PCB-RULER
@laserdan thank you! Will give it a look!
Its made by digital-key DKS-PCB-RULER-ND
Thanks for sharing
I just wanted to like it anyways. Good work.
12:08 LOL. it's fantastic!
I wonder how bright this would make analog night vision. imagine a gen3+ tube with one of these bad boys. One of the big problems with night vision is the depth of field. Soldiers need to be able to read maps and fight, and switching between the two manually is a pain. If theres a deep enough focal length where everything is in focus thatd be huge.
Where's @HuygensOptics when you need him
We all want you to point it at the stars
Speaking of simple questions. Though this is probably answered somewhere online. But why does the focal length impact light gathering? On the surface Id think only the appature size matters? How is light that enters ending up impacting the image media less just because the focal length is different?
Fun with fresnel seems like I have that book somewhere
could you just drill through (or around) that glass and inject oil into the sensor without removing the glass?
so the oil is like a optical taper
In that case, i wonder if planar fresnel exist. Neat! Also, wouldn't it be cool if now that we have mirrorless cameras, they had a full block of glass that extended to the lens and you added a little oil? Lol
Woah! It lives!!!! 😀
Do you need to remove the glass on the sensor? What if you flooded it with oil - does the sensor glass IoR match?
outstanding
Woo new video!
6:47 ohhhh daaaayyymmmmm
[Edit: I thought the lens was made from oil with materials that refocus light all wrapped up in silica or plastic]
This is probably as close as I will see to my polypropylene morphing eye lens and concave image sensor.
Come to think of it - why hasn't anybody tried to build a non-flat, e.g. concave image sensor? Wouldn't that make the required lens systes way simpler and remove most spheric effects?
I wonder if its good at astrophotography?
Infinity at f0.38?
I so love Lasers like i hate optical math ...😂
Hello again long time no see lol
Thor labs sell an index matching gel. I wonder if that would work?
Congratulations on calling it a f-number, not a f-stop 😊
In Sciene We Trust... And Verify. 🧬
Why is it called fast?
I asked a friend and he said it's because you can use a faster shutter speed.
Woohoo I'm early
wonder what f you could get from a extra large frenel lens... i got 1 that is about 3 feet across, i got a bigger one but it's currently inside an old projection tv, that 1 was flat out made to display images....now granted those were in 480i maybe 480p but still!
Maybe the laser engraver could have eased removal of the glass cover.
I’m 2 seconds in and stoked
I thought the f number was something completely different 😮
Immersion lithography stepper lens.
you are awesome
joy
If you had a bunch of sensors, then you could've put one in the oven (to its accepted temp) and then quickly done the glass removal (with the glue to glass method) by clamping the part you glued into a vise and pulled the chip up. Just a thought. This would always result in the broken pieces of glass falling down, and away from the sensor. Just a thought. This is how i delid cpus. I never do it upwards, because i'm too chikensh!t to potentially ruin it by something dropping inside.
Fascinating. I’m trying to wrap my head around refraction behavior, intuitively expecting wavelength dependent blur closer to the edge (rendering it useless for non-monochrome imagery) but apparently that is not happening 🤔
Large apertures woo
Interesting. So this means that the convention of f-number is u clear. NA is quite easy to understand, since it's just half the opening angle at wafer/sensor/film. But the focal distance is the distance of your wafer/sensor/film to Something™.
I find it a bit strange to define this hypothetical plane as curved. Of course in a perfect lens, your wavefront is spherical, so it makes sense to define a curved plane. But in my opinion, the diameter of an opening pupil should not be defined as curved. For example let's say we have a sphere of radius 1 meter. Then you'd assume that the diameter is 2 meters, right? But if I follow this f-number definition, instead you should measure the diameter along the surface and end up with a diameter of pi.
Of course this is convention and we decide how we define things. But this makes me feel slightly uncomfortable. Maybe we should stop talking about f-numbers and just only use NA. I'm sure that would at least make lithographers like me happy!
Math is just an approximation of reality not reality it self. There are so many details that math ignores and a reality math formula that accounts for everything would be as long as a book.
Hello wonderful person watching this amazing Applied Science video
👋
I want to try this, but it appears that lens costs $1850 😆☹
I also enjoy photon manipulation.
Omg!! Fast lenses and science YESSS !! im in the first row baby😎😎
At last
I made a lens using a klien bottle for the objective and a tesseract for the camera. It's a -3.5 focal length
The math at the end reminded me we I decided not to pursue the polypropylene morphing eye.