Why Distance Doesn't Affect Exposure

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You may know about the Inverse Square Law when it comes to light... but does the Inverse Square Law affect the way we expose an image?
Maybe you never thought of it, but a random Roger Ebert quote in Citizen Kane got this myth stuck in my head - and now I'm going to explain why distance doesn't affect exposure.
#Exposure #Photography #Lighting #InverseSquareLaw #RogerEbert

[@NomeDeArte]

Already knew the answer before you started talking. But is not because I'm a cinematographer genius, is because all the data and physics I learned in this channel. So, thank you John for share your amazing knowledge about this art!

[@kotaoshio]

The more I watch the content in this channel,the more I wonder why there aren’t more subscribers to this channel. A cheerful job, very interesting topic, very good narration., thank you

[@mochajohnson4780]

Also figure that to get everything in focus, they had to use a very small aperture... thus requiring much more lighting to achieve proper exposure.

[@sclogse1]

One of The ways around that now is to shoot a plate of the environment and blend it into (add a layer of it in Photoshop) the footage where you can't hide lights. Shadows will have no buzzing graininess.

[@FilmmakerIQ]

Ain't no Photoshop in Citizen Kane

[@MichaelFrazierTube]

my heart did a mini belly flop atop my stomach when i saw you posted...thats all...yup.

[@crimzongaming5470]

Saw that title and thought, "WHOOPS! Time to drop some maths in this guy's lap." Happy to see you already had all your ducks in a row and nailed this one. Roger Ebert should have reviewed any photography texts he had. Great video. :D

[@thesurfacelevelgamer]

Fortunately, that was the last time Roger Ebert made an uninformed assertion about a subject he did not care to research in the slightest.

[@BaltaBueno]

What is the track you use for your outro? It's very catchy

[@seanmckinnon4612]

It’s like how most people assume that throw distance factors into how powerful a projection lamp needs to be however that it not the case it is simply screen (or image) size.

[@oldtvnut]

When I saw the title, I thought "what the heck?" Is it really true that a significant number of people have said that it's the distance from the camera, not the light, that is important? I truly never heard this mistaken idea before.

[@FilmmakerIQ]

Google "exposure and distance" and you'll see it pops up here and there

[@PerEng2405]

You just entered my Hero’s Book.

[@rossmpostpro]

Love the short, concise content Jon. Keep it coming. Much love from the UK.

[@MattMcIrvin]

One place where this breaks is in astronomical photography, where the objects being photographed are so far away that they often have a smaller image size than the film grain or sensor pixel or retina cell, and they effectively register as a point source. At that point, it's overall brightness that matters rather than brightness per solid angle. But! Extended objects like nebulae behave just as you're saying here. I remember being disappointed to realize that those pretty photos of astronomical nebulae generally used big telescope apertures and long exposures, and that the nebulae would be just as dim per solid angle close up as they are far away. If you could go visit them, you wouldn't see something that looks like a Hubble telescope photo; it would be far more drab.

[@MattMcIrvin]

Also! This bears on a famous cosmological conundrum called Olbers' paradox. Suppose the universe is full of stars (or, if you like, galaxies) with a more or less uniform distribution on the very largest scales. Consider the stars within some finite range of distances from the Earth, forming a spherical shell. The contribution to average image brightness per solid angle, from that entire shell, is actually independent of the radius of the shell. It should be the same for nearby shells as for distant ones. So if the galaxies go off to infinity... with all that light adding up from each concentric shell... why is the sky dark at night? (The answer: the universe is only finitely old, and light travels at finite speed, so there's a limit to how far we can see out! Believe it or not, the first person to publicly guess this answer seems to have been Edgar Allan Poe. Also, the light from the furthest shells is subject to cosmological redshift, though this effect is secondary.)

[@AwesomeShotStudios]

Dig your set and content. Keep the great stuff coming. It's appreciated.

[@chuckleberryflin]

John. I love the desk set up, it's so cozy 📽 🙂

[@Metaldetectiontubeworldwide]

Great your are , Jedi master yoda 😉 I didn't saw this one comming , knowing alot of phisics with an appetite for cinema and filmmaking. I was very suprised to hear you debunking this myth . Hear you explanning it , i makes such good sense and logic , well done 🙌 Grtzz john

[@barrycrowder]

For a practical application of this, you can shoot the moon at night time using "sunny 16."

[@MattMcIrvin]

@DrGrandpa Because the material of the Moon's surface, while lit by full sun, is inherently quite dark (not black, but a dark-ish gray similar to worn asphalt).

[@BobH7777]

I am most interested in the point that deep focus uses small apertures to gain depth of field. So lots of light needed to get the deep focus. I wonder what the film speed and exposures were back then.

[@FilmmakerIQ]

Most of the film was shot around f/8- f/16 - there was an article Gregg Toland wrote in American Cinematographer. I would believe the film would have been rated between ASA 25 and 50 but don't quote me on that...

[@sclogse1]

Remember there was push and pull processing back then.

[@JimRobinson-colors]

I can definitely see how Ebert could imagine that. Even in a high school play - the lights might be across the front and everything deeper onto the stage to be lit up would require lights to be turned on back there. The natural way of thinking would be that in film the shadows are where the light can't get to. Really interesting subject matter for discussion. Thanks for that. You must have something on your set that is reflecting or sending a very green cast. Your right arm - skin is very green. ( check it at 5:12 - might be there before that but that is when I noticed it. ) and like all things like that I was distracted and had to roll back your video and ignore it, to take in your dialogue. Going back and viewing your videos - really enjoying them.

[@FilmmakerIQ]

I was playing with colored lighting! Surprised it took 5 minutes to notice it as it's the very first shot.

[@JimRobinson-colors]

@@FilmmakerIQ I was fixated with your excellent banter and didn't notice until then.

[@alantuttphotography]

I always wondered why the inverse square law didn't apply here, and now I understand. Doubling the camera to subject distance might give the camera only 1/4 the light, but that light is hitting only 1/4 of the area of the film or sensor, making the light density the same. But then this brings up the question about why the focus length of the lens doesn't change the formula, because that changes the magnification of the subject on the film or sensor. I bet it has something to do with the fact that an F-stop is a proportional measurement based on the focal length of the lens, with a different sized aperture for the same F-stop depending on the focal length. Right?

[@FilmmakerIQ]

Exactly. If you zoom in without changing the size of the aperture, your F/stop will actually go up - reducing the exposure. But if you have a constant F/stop zoom, the aperture will actually get bigger the more you zoom in thus letting in more light. ;)

[@liortroianovski3626]

Thanks for this great video!! The story I remember hearing though was that Welles insisted on wanting everything foreground & background in focus at all times and since either faster film stocks hadn’t been developed yet or Welles/Toland refused to use them, Toland had to stop down considerably, drastically reducing the amount of light being taken in and thus requiring insane levels of lights to be used (even for the time). I’m not really aware of other films of the era that used such deep focus so this explanation always made sense to me. Anyone else hear anything similar?

[@MarkArandjus]

2:26 = usually my reaction when reading his reviews and such.

[@quite1enough]

amazing explanation, thanks!

[@ManwellWins]

Great explanation as always, keep up the good work! There is a teeny tiny typo at 4:36 though

[@FilmmakerIQ]

got cross i-ed

[@insanejughead]

I like the term lidget, tbh. Also, you explained this so perfectly that I was thinking of this in terms of looking into a light source (or the luminance of a surface). As you move away from the source, the light from it affects a smaller area, but the brightness of that source does not change; only its perceived size based on perspective.

[@FilmmakerIQ]

What's crazy is the sun is no brighter from Mercury's orbit than it is from Pluto - it just takes up a smaller solid angle ;)

[@insanejughead]

@@FilmmakerIQ Yes! Such a solid example. Whereas the area's brightness by the sun is vastly different. Mercury is bathed in light; Pluto is inversely bathed.

[@MattMcIrvin]

@@FilmmakerIQ And on the other side of the coin: with passive imaging optics, no matter how many mirrors or lenses you use, it's not possible to have more sunlight coming in per solid angle than if you were looking at the Sun's photosphere from close up. Which is one way of seeing why concentrated solar power systems can't heat things up to hotter than the surface of the Sun (in practice, the best ones can get a fraction of the way there).

[@CED3]

I could use a break from medical school right about now. Thanks!

[@DHOWSR4DEEPDEPOT]

Wow.....truly interesting. Thanks.

[@randylevy]

Good video. Enjoyed the Hulk arm. ;)

[@robert18productions]

Interesting video. I just wanted to make sure I am not getting anything wrong here, using your example, if the distance from the subject and the camera does not decrease in the amount of light because as you move the camera away from the subject, the light fall off is proportional with the distance from the subject. Therefore causing an inverse effect. On the other hand, if someone changes the distance from the light to the subject, they are moving the actual light which changes the concentration of light on a certain area causing a difference in exposure. Am I on the right track? Therefore if the camera is using a zoom lens with a variable aperture (most kit lenses), the light fall off when zooming in is because the lens has a higher magnification or a narrower angle of view which changes the solid angle in a way as to have a lower exposure. So a constant aperture zoom lens actually has to compensate with moving lens groups/elements in front of the aperture, and the even the size of the aperture itself to get the same exposure. So, is why my Nikkor AI 35-70mm f/3.5 zoom lens' aperture blades do not seem fully opened? When at f/3.5 at 35mm the lens is compensating for the lower magnification and wider angle of view that might cause an increase in the exposure at 35mm when compared to 70mm which the blades seem to be fully open.

[@FilmmakerIQ]

First, light always falls off with distance whether it's from a light source or of it's incident light bouncing off a subject. The reason it doesn't affect exposure for subjects is because distance also affects the angle of view in the exact opposite amount. It's not an inverse effect, it's a balanced effect between distance and the angle of view of the object. Moving a light source does reduce the light that falls on object but we still have to deal with the incidental light between camera and object. Now onto your zoom lens question. The f-stop is defined as your focal length divided by your aperture diameter. So an F/2 35mm has half the diameter aperture as an F/2 70mm lens. I never thought of the solid angle way of explaining it, but it's absolutely right.

[@robert18productions]

⁠​⁠​⁠@@FilmmakerIQ Thanks for answering my questions. I think I fully understand it.

[@jayt8784]

The most obvious example is a landscape or crowd shot outdoors on a sunny day. Everything has the same light - the sun - but objects far away are not darker than those close to the camera.

[@theatifaks]

Learned a lot. Thanks.

[@manicdan481]

Alternate conclusion: The area of space he was trying to light up increases, because the camera is further away, and has a much bigger scene in frame. In your example, it would be like the goal was to always have 10,000 pixels maxed out with lidgets, and as you move the camera closer and further (same lens FOV), the light needed to fill those pixels follows the inverse square law.

[@FilmmakerIQ]

That's even more confusing than what I said.

[@TheNjordy]

Thank you! I was confused by this for years!!!!!

[@FilmmakerIQ]

Thank God I'm not the only one!!!

[@pablovi77]

Well, he was not a cinematographer. And probably just heard it wrong or interpreted wrong. You do generally use higher wattage or more powerful lights to light a background, because you have to put lights farther away, or they’ll be in frame, and you generally can put foreground lights closer to the talent.

[@FilmmakerIQ]

I said the exact same thing in the video.

[@pablovi77]

Filmmaker IQ Yeah, I wrote this right after the Roger Ebert quote, and find out you said that at the end.

[@dustinjenkins8215]

Literally just thought about this yesterday.

[@StepbyStepPhotographyandVideo]

FINALLY! I've been thinking this lately as well

[@StepbyStepPhotographyandVideo]

You killed me with the masterclass cut away LOL

[@FilmmakerIQ]

I say that line probably at least once a day.

[@StepbyStepPhotographyandVideo]

@@FilmmakerIQ ironically, to me, that's what hes most known for

[@vilmarmoccelin]

Thank you again for a great class! After the "lidget" explanation is easy to see why in a situation where the focal length stay the same you will keep the same exposure. If you just add distance the subject will be smaller in the frame so even with less lumens reaching the sensor these lumens will result in the same excitation of the fewer pixels being excited. But if you, for some reason manipulate the focal lenght with the subject still using roughly the same quantity of pixels in the frame you will need more light to keep the exposure the same as you increase the distance, right??? More distance will result in less lumens reaching the sensor, but with the same quantity of pixels to be excited you will have, as a result, less lumens per pixel, so something will need to be changed for the exposure remains the same. So why I don't see a substancial exposure variation in dolly zoom shots? The difference is so sutil that I can't see, there is a exposure manipulation or I'm missing something?

[@FilmmakerIQ]

THIS IS A GREAT QUESTION!!! So say you double the focal length on the 10m shot WITHOUT changing the physical size of the aperture. What's going to happen is your 100 lidgets is now going to be spread over a box that's 20x20... Same amount of light but over an area 4 times as large. So it will be 2 stops darker! Now remember what f/stop ratio is: it's focal length divided by diameter of the aperture. If we didn't change the aperture size the fstop will actually drop 2 stops if we double the focal length. So in order to retain the exposure we have to double the diameter of the aperture to compensate. Doing so will let in more light... In other words more lidgets! ;)

[@TaranVH]

@@FilmmakerIQ woah, this explains why I have to increase the fauxsposure on close-up shots all the time. (That's my word for adjusting "exposure" in post)

[@FilmmakerIQ]

Well that depends on the kind of lens you have. Constant fstop zooms will not give you a lesser exposure when zoomed in but lots of lens do have different minimum fstop depending on where you are in the zoom.

[@jg3615207]

6:42 But what if i used a zoom lens and zoom in to the image wouldn't i still get the same exposure to the same pixels?

[@FilmmakerIQ]

If you zoomed without changing the actual size of your aperture, you would take the same amount of light (same lidgets) but spread them over a bigger area, in other words your exposure would be lower. The only way to keep the exposure constant is to let more light in the further you zoom... That means keeping your f/stop constant which means you have a bigger Aperture at higher zooms than at lower zooms

[@sclogse1]

@@FilmmakerIQ It's movie making. Whatever works.

[@FilmmakerIQ]

No, this is about exposure. There's an actual science here. Movie making is the result of the science. Doesn't mean the science underlying is not important.

[@NatesFilmTutorials]

Further the subject is from the camera... the more likely the lights need to be further from the subject. Which would require more light unless the light could be moved closer or hidden. I'm sure Ebert was making a relative statement. I never heard it said like that, which does sound quite confusing. Thanks for clearing it up John Hess! #lidgets

[@FilmmakerIQ]

That's not the way Ebert said it...

[@gregkrazanski]

listening to what he's saying i'm pretty sure he just means that because the subject is far away, the lights also kind of have to be far away, so he needed stronger lights to light her up because they couldn't put the lights that close in a wide shot like this. I have to conclude that because I've never heard of this misconception before, it's like thinking that if you walked backwards away from something it would get darker, no one thinks that.

[@FilmmakerIQ]

That's not what he said though. You have to make a pretty drastic leap to get to your conclusion based on what he said.

[@FilmmakerIQ]

And that particular shot didn't require the super big lights, you could hide the light pretty close.

[@gregkrazanski]

​@@FilmmakerIQ I guess we disagree that it's drastic. I can see from all your responses that you really like believing or want to believe that he meant exactly what he said. And I get that the 18 year old you without much experience came away from this commentary with misinformation. Fair enough. I will say that if in my life, if I took every phrase uttered by anyone around me exactly and literally without running it through a "common sense" filter that at least forced me to to a double-take, I'd probably still be trying to process things from years ago. Not saying you should have done this at 18 years old, but like I said, this concept is equivalent to backing away from something and thinking it will get darker the further you move, it just doesn't add up. I don't believe that Roger Ebert believed that, so I think he must ultimately be talking about the distance of the lights.

[@FilmmakerIQ]

He said, "The further away from the camera the more light must be on you in order for you show up - it takes less light in the foreground than in the background" He outlined distance from the camera to the subject as one variable, and the light on a person as the second variable. And if you have the basic grasp of the inverse square law when it comes to the falloff of light - Ebert's statement makes complete sense. Ebert to me at 18 was a tower of film knowledge and the inverse square law seemed to jive with that statement so I believed maybe that's just the way cameras worked... I've had discussions with people that have tried to wedge distance into the exposure equation and another commenter who told me his photography teacher explained this very myth that distance affects exposure. Again I am basing it on the actual words he used, I am not introducing a "well what he meant was..." analysis. Maybe he meant it the other way, but that doesn't change the fact that what he said on the commentary was just wrong. As for positioning of lights - well check out a sitcom set and you'll see they hide the lights above and use just as big a light to light foreground as they do background. So no, you don't need less light in the foreground than in the background...

[@mytech6779]

For clarification I must point out that when zooming in rather than pushing in, that is where you get the inverse square drop in lux. Of course being further away you could also open the aperture without much reduction in depth of field.

[@FilmmakerIQ]

More clarification is needed if you want to include zooming in. Zooming in without changing the aperture size results in an decrease of f/stop. The drop in exposure has nothing to do with the distance (all distances will equally reduce in exposure) and everything to do with magnification power of the lens.

[@ThomasLuca]

I couldn't agree with you more, John. Filmmakers as well as critics these days do not study Cinema history enough and Forced Perspective is great especially with miniatures. But keep in mind in those days they filmed on good ol' 35 mm film and celluloid is much different from digital in many ways. We love Kodak MPF but Technicolor was king before Kodak became popular or trustworthy by studios. These days digital cinema cameras are different in many aspects. Plus lights were hot whereas LED are relatively no heat.

[@insanejughead]

Me: "I know everything about film lighting and inverse square law." John Hess: "Here's where Ebert was wrong about lighting in a movie." *Is absolutely right* Me: "Dammit! How could this have happened."

[@22freedom33]

These videos are so helpfull

[@MrJayColes]

On a separate note, the focal distance that your lens is set at has an effect on the amount of light that hits the sensor. As you rack focus from infinity to mins, the exposure drops.

[@FilmmakerIQ]

We don't usually think of it that way but you are absolutely right. It's gives credence to the idea that a blurry background helps separate it from the foreground. When I did my dynamic range testing I used the focus to precisely control the exposure of my testing dots.

[@MrJayColes]

Indeed. Fun fact, arri signature primes don’t experience this exposure drop.

[@FilmmakerIQ]

That's not true - take a shot of a Christmas light in focus. It might sit at say 95IRE - now blur it out - the blur will no longer measure 95IRE - it will drop in exposure. This will happen regardless the lens. Perhaps what you were originally talking about were lens breathing - I'm talking about something different.

[@MrJayColes]

@@FilmmakerIQnot talking about lens breathing. Test it with a signature prime and some baking paper over the lens. As you rack focus the exposure won’t change.

[@theportraitist4888]

Fascinating subject, thanks! While I never assumed that falsehood to be true (which is good), I also never pondered why. Now that I am, I think it can be summed up a bit simpler than all that math. The Inverse Square Law is applied to lights which SPREAD. So, a Fresnel with a 1-foot diameter has light that spreads over, say, a 10'x10' area when it hits the set. Like spreading a tab of butter over a piece of toast, the only way is to thin it out. Or in the case of light, lower the intensity. But when we TAKE a photograph, we aren't taking a photo of light that is SPREADING. We are taking a photo of light that is REFLECTING. In other words, we are just photographing the light that is on a straight line to the camera. Sure reflected light can spread too, but we aren't even seeing all of that, no matter how far or close the camera is. We only see the non-spreading light, which essentially doesn't diminish or get affected by the ISL. At least not significantly, which is why we can see things like nighttime cityscapes, and stars in the sky! In both cases, the twinkling light may get smaller, but not significantly darker, despite the varying distances.

[@FilmmakerIQ]

The math is SO much simpler and more accurate than what you wrote :P

[@theportraitist4888]

@@FilmmakerIQ Because we all know how much artists and creatives love math, eh? I'll take another look at your math, but think the conceptual approach worked better for my brain. Either way, thanks again, I enjoyed the topic!

[@FilmmakerIQ]

One thing in your analogy... All light "spreads". Reflected light is subject to the inverse square law just the same as a light source. You're close but the math is so much simpler and elegant way of understanding it. ;)

[@theportraitist4888]

@@FilmmakerIQ We all understand things differently. I'll stick with my pat of butter understanding. While not perfect, it gets me close enough. ;-)

[@FilmmakerIQ]

Just be careful - people make analogies that sound mighty fine but they can lead you to some really screwy conclusions - I think the same thing happened to Ebert ;)

[@sclogse1]

Welles knew the advantage of mirrors and reflectors.

[@jonaslinter]

One way in which you could say distance affects exposure would be when talking about focus distance. Focusing on something close changes the focal lenght and with that, the effective aperture which affects exposure. Although that really only becomes a problem in macro photography. This brings me to an interesting question. Fancy cinema lenses compensate for the focal lenght change of focusing to reduce focus breathing. Does that eliminate the change of the effective aperture too?

[@FilmmakerIQ]

The effective aperture might change but the f stop ratio stays the same (any minute change in aperture is countered by the exact same change in focal length). Therefore there is no change in exposure.

[@jonaslinter]

@@FilmmakerIQ Thanks for the answer. I'm glad I found this channel. I like how your explanations cover the necessary details. Photography seems to hold many concepts that can easily be explained badly, causing much confusion in the long run. With your videos I feel like I really gained a deeper understanding of the subject.

[@FilmmakerIQ]

Yeah it's really frustrating. There are so many concepts that people sort of half-ass tell people on the internet. Getting to the real truth takes a bit of effort that a lot of people aren't willing to put into a "hobby" - so half truths persist.

[@GuilhermeCaspar]

7:10 scource or source, in last line? Hug and thanks.

[@FilmmakerIQ]

Are you really asking or just wanted to point out the typo? :P

[@PrimoWorks]

Well, he didn’t say exposure... he said for the characters to show up. This would actually make sense, because the smaller the object is in the frame, the less it pops up. So if you over exposed it a little, the character will be more easily spotted. I love you videos! I think this one, even though we learn something, comes from the wrong angle. Thanks!

[@FilmmakerIQ]

But that's not correct. You don't want to overexpose the background.

[@FilmmakerIQ]

That's not true either.

[@dpkdz]

@@ckellyedits the moon is soo damn far away from Earth. you think its underexposed or what.

[@ThomasLuca]

In the 1920s and '30s, studios discovered that pictures were more pleasing with a soft look shot just outside of England or in England, instead of California due to the cloud coverage, rain and fog. Diffused light. That was with Technicolor. Of course every DP worth their weight in salt knows that these days but it was first discovered then and championed by Natalie Kalmus, the ex-wife of Technicolor inventor, Herbert Kalmus. The Dr. didn't really seem to be enthused with Cinema?

[@Derpy1969]

7:13 Distance from the light.... scource?

[@jasonschubert6828]

Apparently there was no outside editing.

[@rib9985]

Can you also say the sensors and photo-sensitive film are affected by photons and this is why the exposure stays the same? With photons being reflected from a subject, and it being a constant energy source, the exposure stays the same in a given area...

[@FilmmakerIQ]

I don't think a distinction needs to be made. It is the photons that enable exposure in any medium.

[@veggiet2009]

Or Ebert just misspoke, it's not too much of a stretch to think that while he said "distance from camera" he meant to say "distance from lights"

[@FilmmakerIQ]

But he clarified himself. I don't think he misspoke, I think he heard it one way and repeated it without knowing.

[@zupperm]

I read that as you need more light if you’re on the background to be visible in subjective sense. Or else the viewer’s brain is going to focus on the guy who’s larger on the frame.

[@FilmmakerIQ]

But that's not true either...

[@zupperm]

Filmmaker IQ but in 1:44 the man looks darker than the woman. That could be done on purpose to compensate for the apparent size difference. This is not true for all scenes and I don’t know if Ebert refered to this scene specifically

[@FilmmakerIQ]

The man in the foreground isn't lit at all. That was intentional, he's the investigator into Kane's life, as I remember he's usual shown in shadow. Dorothy Commingore is the subject of interest. But that's not what Ebert was saying in this commentary. I wrote out what he said... And if he misspoke, well the 19 year old me accepted it as fact.

[@rokpodlogar6062]

inverse square law holds true, but in relation with distance of the light to the subject not the camera as it's not the light source that creates the image but the light reflected from the subject that hits the camera. and the further the light source is from the subject, less particles hit the subject directly. ofcourse over large distances even the distance between the camera and subject would recieve shortage off reflected light, since light bounces off at all possible angles.

[@FilmmakerIQ]

Light bouncing off an object is still a light source. Watch the video.

[@rokpodlogar6062]

@@FilmmakerIQ true. but.. practically speaking, every photon of emitted light has the potential to miss the camera lens, and that potential increases with distances. with a point light origin, the greater the distance from the source, the smaller the angle of incoming stream of photons will be. less photon = less light. and each time a photon bounces, the chance of it missing another point in space increases with distance. also don't forget different "color" materials reflect light differently. otherwise why not just use black reflectors for side light, eh? :)

[@FilmmakerIQ]

Watch the video....

[@Mulletmanalive]

I think what Ebert was failing to explain was that to get her to come out in focus in f8-11, they had to absolutely hammer both parties with light, her more so as she seems a half stop brighter anyway. That scene is legendary because they had to reapply her makeup repeatedly because of the heat. It was made worse because arcs don’t show up nearly as well on bw photography

[@FilmmakerIQ]

They didn't hammer the foreground with light, it's in shadow ;)

[@kenh.5903]

Late to the party. I just found this video. I'm mystified by how anyone could believe moving the camera would be the same as moving the lights essentially. Bizarre

[@FilmmakerIQ]

I think it'll be a simple misunderstanding of the distance squared law

[@DavidSdeLis]

Magistral!

[@InTeCredo]

Still no subtitles?

[@FilmmakerIQ]

just published

[@selecol101]

Awesoooome!

[@Sheevlord]

Ebert also said that video games don't count as art, so I'd take anything he said with a grain of salt.

[@FilmmakerIQ]

To be fair, he said it before games really because artful. He was still thinking pong

[@emilguldmann6816]

Thanks! I had a photography teacher tell me exposure settings mattered a lot when changing camera distance. What cognitive dissonance!

[@FilmmakerIQ]

I have had people give me guff about this not being a myth so I guess I'm kind of glad that you had a teacher I told you that...lol

[@oarudis]

The only thing i could see more light being needed, is to focus your eyes to an object. In a B&W movie more light would benefit if you are to spotlight an object or person. In a scene were everything is in focus how can you make the eye focus on one person. Spotlight them, like theater.

[@FilmmakerIQ]

But spotlighting is not dependent on the distance to the camera.

[@oarudis]

Filmmaker IQ no, but for that b&w movie more light is needed to have the distant object stand more than the other objects.

[@FilmmakerIQ]

@@oarudis no that's not true. Distance to camera plays no role in an objects brightness regardless of color or black and white.

[@oarudis]

@@FilmmakerIQ distance of light does. Camera needs light for it take in the details of an object that your filming. maybe Ebert was trying to say that.

[@FilmmakerIQ]

Misread your comment. Distance to light affects how much light falls on you yes. But what Ebert said about needing more light falling on you the further from the camera is completely wrong. That's the whole point of the video.

[@BobSchoepenjr]

I understood this and I even don’t like math. Grts from Belgium

[@Tmanaz480]

In other words, the inverse square law comes into play between the light source and the subject, NOT between the subject and the lens.

[@FilmmakerIQ]

No the inverse square law works between the subject and the lens too...

[@houssamjaridi6214]

i love you jhon you are best

[@kozmagergely]

Ebert is a film critic, he's not one of us. He'd like to be but he's the one tasting the egg and giving his opinion on it. Can't cook an egg though. Great critic, but only a critic, with all due respect!

[@Quetzalcoatl0]

I have a rant about 24p and i think i have strong points on why it sucks for youtube. I've tried to make a youtuber switch but i guess he was ignoring me. I know you are technical enough to understand my points (because i've watched all your videos from the past 2+ years)

[@FilmmakerIQ]

I strongly disagree that it sucks for KZbin. KZbin is great with 24 fps.

[@Quetzalcoatl0]

@@FilmmakerIQ I love when i play a movie (24p) on the TV that has a 24p mode. It's perfectly smooth because each frame is shown only once per cycle. But KZbin doesn't have an option to change the screens (on the supported ones) frequency to match the framerate of the video (yet). The problem is that 99% of the screens (tvs, monitors, phones, ect) are at 60hz fixed. So a 24p will have to duplicate frames in odd ways. 30fps fits perfectly in a 60hz display. Each frame is duplicated exactly 2 times. But a 24p video will have frames duplicated 2 times and 3 times. This inconsistency makes the video choppy than it really is. When someone uploads a video in 4k or 8k for example some nature shots or bird eye shots that are super smooth, i have to force my monitor to 48hz. This way 24p fits exactly 2 times in 48, which makes such a big difference. Until KZbin finds a way to force a screens (the ones with variable refresh rates) refresh rate to match the video fps (even if it duplicates frames), shooting 24p on KZbin kinds of sucks. While 30p works everywhere by default. EDIT: On analog TV PAL represents ~25fps which is 2x less then the power lines frequency (50hz) in EU and NTSC represents ~30fps which is 2x less then the power lines frequency(60hz) in America. Because each frame will be duplicated exactly 2 times, resulting a smooth picture. Not in the case of KZbin, because 99% of the screens run at 60fps.

[@FilmmakerIQ]

First of all not 99% of monitor screens are 60hz - There are a lot of higher refresh rate monitors being sold these days. I can't find market share right now but it's not 99%. It may be closer to like 90%. Secondly the issues with 3:2 pulldown are way way way overblown. We're talking a difference of 1/60th of a second between frames that occurs 12 times a second. Sure I can pick it out if I'm watching super carefully and comparing it to a 48hz monitor... but here's the thing. I grew up watching 3:2 pulldown. If you watch TV in NTSC land, that's just the way it is. As a kid I wore out all sorts of VHS tapes that utilized the 3:2 pulldown. It looks perfectly natural to me and what a film ought to look like. I did a quick test and found that I actually prefer the 3:2 with 60hz than 2:2 with 48hz. Now okay, maybe you don't have the experience I do... but your options are pretty simple - set your screen to either 48, 72, 96, 120, 144hz... and you get your even pulldowns. 30p creates issues at all of those rates except for 120. Let's not even start with 25p... (which I find perfectly acceptable on a 60hz monitor 2:3:2:3:2 pulldown). So ultimately KZbin plays great with 24fps. Especially since it's natively serving you 24fps streams and your display's processor does the pulldown. There's no reason why you shouldn't upload 24fps content to KZbin. Few frames, better compression. BTW, PAL and NTSC are only effective 25fps and 30fps - in analog they are really 50i and 60i respectively. This is has a drastically different look and is closer to a 50fps and 60fps look.

[@Quetzalcoatl0]

@@FilmmakerIQ Fair point. I'm only 24 years old. I have a quite a bit of analog tube TV watching, but i've never noticed or even though about it. I've played a ton of PC games thou. I have a lot more time behind a monitor than a TV. Yes my point for 99% is wrong, i wanted to say that the majority are still 60. I myself have a 100hz one with G-sync but g-sync doesn't work on the browser (yet). So i have to manually switch my fps to the desired one. Sometimes that doesn't work because it's not a native refresh rate, but a custom one from the nvidia control panel. that's why i'm setting it to 48fps and not 24 because that's supported. On most videos i can't notice the 3:2 pulldown, because they don't have a lot of smooth movement. But almost all drone footage is stuttery , and it's quite a bit stuttery, making it almost unwatchable. Oh well. that was my rant :D. Looking forward to new videos.

[@FilmmakerIQ]

I've been doing a lot of drone cinematography lately. The stutteriness is not due to the 3:2 pulldown. It's due to shooting with higher shutter speeds and moving too fast. Most drones need ND filters to get good footage can you have to be very careful about how you control your speed and motion.

[@arsenymun2028]

Roger Ebert was often wrong

[@TaranVH]

Video games are not art!

[@branting2]

@@TaranVH He did indeed say that. 🤣 In all seriousness though, came here after watching your treehouse build. Keep up the good work, Taran! 👍

[@Tmanaz480]

TBF, critics evaluate films esthetically and artistically. The science and technology is secondary.

[@girlperson1]

Farther.

[@MrBluesfly]

Joe McNally smash cut at 7.01

[@vinniemorciglio4632]

A little bit of knowledge is a dangerous thing. He had the right idea, but the wrong example........again.....

[@Gregg0Palmer]

I miss the red shirt.....

[@andlabs]

From the author of I Hated Hated Hated This Focus, Your Photography Sucks, and Roger Ebert's Four-Step Exposures

[@sclogse1]

Ebert may have been wrong, but he swam with the fishes in Russ Meyer's pool...

[@denizkendirci]

why distance doesn't affect exposure: "because it's photography, not sonography."

[@dangerdac]

I was told there would be no math

[@mrsnoo86]

hi

[@gotherecom]

Incident light vs. reflected light, or why is Venus so bright in the evening sky? That is why spot meters were invented.

[@FilmmakerIQ]

It's all the same light baby

[@nassersi]

you have green hand...like "vodník" ;-D

[@StepbyStepPhotographyandVideo]

It does take less light in the foreground than the background because THERES LESS SURFACE AREA TO LIGHT.

[@FilmmakerIQ]

I'm not sure I follow your logic...

[@StepbyStepPhotographyandVideo]

@@FilmmakerIQ my half thought out opinion probably can be argued based on style choice of filming but if you have a closeup on an actor you can light them with the camera right outside the shot and use less light than you'll need to light the large scenic background behind them.

[@FilmmakerIQ]

Okay yes... but I did say that in the video itself.

[@StepbyStepPhotographyandVideo]

@@FilmmakerIQ yes and I enjoy being wrong as a general practice of humility ;)

[@BadKarma714]

Who are you to question the great Roger Ebert what do you know someone will say in the comments lol I hope not loved the video.

[@Derpy1969]

BadKarma 714 Ebert was a critic, not a filmmaker. And he was wrong because he didn’t math.

[@BadKarma714]

@@Derpy1969 lol I was being sarcastic by joking because of the 24FPS video and I know who Ebert is I use to watch him on a show called at the Movies lol what's he didn't math 😂

[@LavianoTS386]

Yeah, I agree, he just misspoke.

[@FilmmakerIQ]

Well his "misspoke" was pretty clear to me that I believed it for years.

[@reggiebenes2916]

So Roger Ebert was wrong, just like 75% of his movie reviews.

[@patrickshields5251]

Is this the only fact that Roger Ebert got wrong in his DVD commentary?

[@FilmmakerIQ]

It's the one I remembered for 20 years.

[@patrickshields5251]

Then I call that a big yes. It's still a historically accurate commentary, it's just that it's scientific accuracy is 90% correct.

[@FilmmakerIQ]

So what? This wasn't a condemnation of the commentary - just that one line.

[@patrickshields5251]

@@FilmmakerIQ Oh, my mistake.

[@FilmmakerIQ]

Ebert was one of the my heroes that fostered my love of film to the point where I could consider a career in the field.

[@Trusteft]

No one is perfect. While Ebert was a name I always heard of when dealing with movies, I think in all my life (I am just past 42) I never read more than perhaps one of his reviews. Even when I was studying film, I don't remember...hmm, perhaps there, my mind isn't what it used to be. Regardless, no one is perfect and one of the first things I was taught at university was to never take what you are taught as the holy truth, always do your own research. My point is, good video. Thank you for sharing.

[@DarkAngelEU]

The explanation you give at the end is how I interpreted the remark from Roger Ebert, so either my English sucks, or you're being really snotty about misinterpreting something really easy to understand and just made a monetized video about it.

[@FilmmakerIQ]

Your English sucks then because that's not how I and others interpreted it. Your comment's kinda snotty too.

[@DarkAngelEU]

@@FilmmakerIQ Lol, noted.

[@radiozelaza]

allegedly a lidget...

[@emanuelbinder4263]

Of course it's all about the distance from the LIGHT source not the CAMERA. Very basic concept both in photography and cinematography. The guy just misspoke.

[@FilmmakerIQ]

Not of course, had a long conversation on this very topic with someone else in Twitter. ;) And it's a valid question, why doesn't the exposure change if the inverse square law states that light diminishes by the square of the distance. A subject is just as much a light source (reflected light) as is a lighting instrument.

[@maytherdigital3300]

Sounds lidget.

[@CanadienAtheist]

Who listens to film critics?