The question at 52:50. The question reiterated by Joe contains the first confusion: power versus force delivered. Potential (Watt) versus energy consumed (Watt.seconds) that is. In the international system of units - SI - Joule is equal to Watt.seconds. Manufacturers who understand this, have replaced the Watt.seconds by Joule that is the preferred unit in SI. The difference between a 600 Ws (or J) and 1200 J (or Ws) flash is one F-stop. And between 1200 and 2400 J also one F-stop. What exposure you get from those Joules is another question. Manufacturers sometimes publish a "Guide number"-like value for, say, ISO 100, at 2m distance, with their reflector/modifier type X, of e.g. 64. That is to say for correct exposure at full power at that distance with that ISO and reflector, you would need F-stop 64. "Guide number" is the product - multiplication - of F-stop and matching distance (so it would be 128 in this example). The problem with Guide number is, it depends on the reflector. You'll see one on-camera-flash manufacturer report Guide number at (assuming 24mm x 36mm sensor) 35mm wide angle lens reflector zoom and another list the Guide number for 100mm. If the numbers are the same, the last is much less powerful. The problem with Joules (or Ws) is, they refer to the energy put into one flash. Not power. Not light put out. The efficiency of the electronics routing that energy to the lamp and the efficiency of the flash bulb itself, are only part of where we lose energy. 1 Joule = 1 Watt second 1 Watt = 1 Watt second/second = 1 Joule/second. If we want to convert the Joules number of a flash into Watts, the formula is simple: Take e.g. a 1200 J (or Ws) broncolor pack. Let's say the flash duration at full power is 1/800th sec (0.00125). It power in Watt: 1200 Ws/0.00125 s = 960,000 W. And that is the number you have to compare to constant light with the same efficiency (electricity to light conversion). So, Tony, a _Joule_ is not "sort of different" from a _Watt_second_, but exactly the same. And Joe, the Watts of a flash are theoretical at the side of the light. Where you plug it into the wall outlet, you have to pay attention. The number specified in Watts or Amps at your mains voltage, is relatively low. Your 1200J pack may pull up to 2000 W out of the mains in order to be able to deliver 1200 Ws (960,000 W) in 1/800th of a second. Watt is about comparing forces so it is standardized to a theoretical 1 second time window. Watt.seconds equal Joules are like the _kilo_Watt_hours_ that your electrical company uses to charge your energy consumption.
Keep up the great work guys!! Love the "creative approach"... its all about choices and learning to use what you have, be it candle-light to sun-light... thanks for keeping it real!!
Great video, thanks a lot. Just one little thing... 3:30 No flash - but also no smile. 3:39 Flash - and now there's a smile. I think that's a very cheap salesman's trick, and I don't think it belongs in an educational video.
Great info! Subscribed! Question please... I'm a cinematographer (Indie films) and getting more and more interested in portrait photography, both with a DSLR and still frames from my 4K cinema camera. I have several lights, softboxes, and modifiers, but it's all continuous video lighting/hot lights. I'd love to see you do a video on using continuous lighting please! I know the concept is essentially the same, but the details and obstacles are a bit different. Thanks again and keep up the great work! :)
How come your Seconic meter requires blocking specular sun light with your finger to get a proper exposure, and yet there is no finger required when working with speedlight in studio? Is it possible that Seconic meter is just badly calibrated? Or perhaps it is not linear enough?
I guess it is because a stobe does not generate a hotspot on the dome. I guess you get the same problem if you got a continues light source that is very concentrated on one spot. (like maybe a small LED pen-light)
Zack My other brand lightmeter gives me perfect sunny 16 reading in full sun, and my exposition is OK (when the sun is behind me). So "hotspot on the dome" argument is not valid.
At 12.30 I guess you mean decrease the shutter speed ? From let's say 1/125th of a second to 1/250th of a second, 125 is the half of 250 but 1/125 is the double of 1/250
No Johan, you are mistaken. Increasing shutter speed means choosing a faster shutter. In this case - they wanted to darken the background by underexposing it 1 stop. How do you underexpose an image - by increasing the speed of the shutter letting in less light.
What is the brand name of the lighting kit you are recommending? I can't quite make it out to search for it. The same company you mentioned where you did the little boy with watermelon.
TO: MsLili - 4:20 I could not agree with you more! I do my best to get it right in camera every time! PS or "post" work is not professional at all. Such a shame to because this young lady is very pretty.
Worst comment ever. To give the best high end quality you need both get it right in camera and fix the cameras limitations and bring the art to life in post.
The question at 52:50. The question reiterated by Joe contains the first confusion: power versus force delivered. Potential (Watt) versus energy consumed (Watt.seconds) that is. In the international system of units - SI - Joule is equal to Watt.seconds. Manufacturers who understand this, have replaced the Watt.seconds by Joule that is the preferred unit in SI.
The difference between a 600 Ws (or J) and 1200 J (or Ws) flash is one F-stop. And between 1200 and 2400 J also one F-stop.
What exposure you get from those Joules is another question. Manufacturers sometimes publish a "Guide number"-like value for, say, ISO 100, at 2m distance, with their reflector/modifier type X, of e.g. 64. That is to say for correct exposure at full power at that distance with that ISO and reflector, you would need F-stop 64. "Guide number" is the product - multiplication - of F-stop and matching distance (so it would be 128 in this example).
The problem with Guide number is, it depends on the reflector. You'll see one on-camera-flash manufacturer report Guide number at (assuming 24mm x 36mm sensor) 35mm wide angle lens reflector zoom and another list the Guide number for 100mm. If the numbers are the same, the last is much less powerful.
The problem with Joules (or Ws) is, they refer to the energy put into one flash. Not power. Not light put out. The efficiency of the electronics routing that energy to the lamp and the efficiency of the flash bulb itself, are only part of where we lose energy.
1 Joule = 1 Watt second
1 Watt = 1 Watt second/second = 1 Joule/second.
If we want to convert the Joules number of a flash into Watts, the formula is simple:
Take e.g. a 1200 J (or Ws) broncolor pack. Let's say the flash duration at full power is 1/800th sec (0.00125). It power in Watt: 1200 Ws/0.00125 s = 960,000 W.
And that is the number you have to compare to constant light with the same efficiency (electricity to light conversion).
So, Tony, a _Joule_ is not "sort of different" from a _Watt_second_, but exactly the same.
And Joe, the Watts of a flash are theoretical at the side of the light. Where you plug it into the wall outlet, you have to pay attention. The number specified in Watts or Amps at your mains voltage, is relatively low. Your 1200J pack may pull up to 2000 W out of the mains in order to be able to deliver 1200 Ws (960,000 W) in 1/800th of a second.
Watt is about comparing forces so it is standardized to a theoretical 1 second time window. Watt.seconds equal Joules are like the _kilo_Watt_hours_ that your electrical company uses to charge your energy consumption.
Keep up the great work guys!! Love the "creative approach"... its all about choices and learning to use what you have, be it candle-light to sun-light... thanks for keeping it real!!
I love your shows. Very interesting and the people who put thumbs down must be your competitors 😃
I really learned a lot guys, thanks!
Thank you for so much information..This was great..
You guys are great keep up the good work
Great video, thanks a lot.
Just one little thing...
3:30 No flash - but also no smile. 3:39 Flash - and now there's a smile.
I think that's a very cheap salesman's trick, and I don't think it belongs in an educational video.
Nice one, educative, thanks.
Great info! Subscribed! Question please... I'm a cinematographer (Indie films) and getting more and more interested in portrait photography, both with a DSLR and still frames from my 4K cinema camera. I have several lights, softboxes, and modifiers, but it's all continuous video lighting/hot lights. I'd love to see you do a video on using continuous lighting please! I know the concept is essentially the same, but the details and obstacles are a bit different. Thanks again and keep up the great work! :)
Thanks guys. This was very educational. #photography
Great work. Thanks for the investment.
Please correct me if I'm wrong.
1 watt = 1 joule/second. Therefore 1 watt second = 1 joule/second * second = 1 joule .
Cool stuff Thx a lot ! I admit I was a little lost.
How come your Seconic meter requires blocking specular sun light with your finger to get a proper exposure, and yet there is no finger required when working with speedlight in studio? Is it possible that Seconic meter is just badly calibrated? Or perhaps it is not linear enough?
I guess it is because a stobe does not generate a hotspot on the dome. I guess you get the same problem if you got a continues light source that is very concentrated on one spot. (like maybe a small LED pen-light)
Zack My other brand lightmeter gives me perfect sunny 16 reading in full sun, and my exposition is OK (when the sun is behind me). So "hotspot on the dome" argument is not valid.
Ja Za and when you stand like that, with the sun behind you, you get the hotspot on the done of that meter?
Zack Of course. I do measure outside my own shadow.
Ja Za When I think we need someone else to answer this for us, because I starting to wonder about why this is so too now.
Your eyes also go to numbers or letters on shirts.
At 12.30 I guess you mean decrease the shutter speed ? From let's say 1/125th of a second to 1/250th of a second, 125 is the half of 250 but 1/125 is the double of 1/250
No Johan, you are mistaken. Increasing shutter speed means choosing a faster shutter. In this case - they wanted to darken the background by underexposing it 1 stop. How do you underexpose an image - by increasing the speed of the shutter letting in less light.
@@phillipsphotography3307 Well, English is not my native language... Great videos btw
Tnk u
What is the brand name of the lighting kit you are recommending? I can't quite make it out to search for it. The same company you mentioned where you did the little boy with watermelon.
Bowens Gemini.
18:21 It looks like he has one hand bigger than the other
Don't know who did the pics editing of the first 16mins pic (Just watched till there) but it is pretty bad, I'm sorry.
Great tips however have you done a session purely focusing on black people?
TO: MsLili - 4:20 I could not agree with you more! I do my best to get it right in camera every time! PS or "post" work is not professional at all. Such a shame to because this young lady is very pretty.
Worst comment ever. To give the best high end quality you need both get it right in camera and fix the cameras limitations and bring the art to life in post.
Great video, but please make shorter videos. Having to watch the whole thing to help me with a shooting assignment isn't cool.
Over edited images, and poor video quality.
I cannot listen to anyone giving advice when the results are so bad! You really need to work on your photoshop technique, awful.
how can u be a talented model?
+Green Plasticbag Work with a model that knows how to model and then one who has never modeled before and you know know.
Flip it and reverse it.