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My misunderstanding/ confusion on (Crop factors) 50mm closet to the Human Eye?


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So, I took a lot of still photos with 50mm lens on full frame film cameras such as the Nikon FM series. 

And I'm a big fan of Robert Bresson and Ozu as such. However, I stumbled upon a few articles presumably states that Bresson used 50mm lens exclusively and then claiming that it is the closet focal length to the human eye. 

Now wait a minute........

Were they all film on 4-perf film with soundtracks back in the day? So by motion picture standards, a 50mm is more or less a 75mm? 

How can that be said about being closet to the human eye???? What did I miss???? 

PS: Bear with me, as I'm still learning. 

 

Read them here: 

https://blogs.iu.edu/aplaceforfilm/2018/11/15/robert-bressons-surrealist-affinities/#:~:text=The 50mm Lens&text=He is famous for always,how the human eye sees.

https://www.rogerdeakins.com/film-talk/call-me-by-your-name-single-lens/

https://www.bfi.org.uk/sight-and-sound/features/notes-from-cinematographer-leonce-henry-burel-on-robert-bresson

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The 50mm is claimed to be close to human eye for full frame. For "super35", the equivalent is 35mm.

But...

The human eye is not a simple lens. And another question is to know what criteria one use to estimate the eye focal length.

If this is the angle of vision, well...

The angle covered by either one eye or the other is over 180°. The angle covered by both eyes simultaneously is like 120° (+/-60° around centre). But one do not really "see" in the surrounding angles, only suspicious movements are detected, and then one turn our eyes to check for any danger. The angle in which one see colours is around 60° (+/-30°). The angle were accuracy is high enough to read text is only 20° (+/-10). And the maximum accuracy is within a pinspot 3-5° angle. Which one of these angles should be used to estimate an equivalent focal length of the human eye ?

Moreover, one cannot isolate the information given by the eyes from the processing performed by the brain. When looking around you, the brain concatenates images from different focus distances and directions, a bit like the panorama mode of some cameras. And it uses the long term memory for object recognition. That way, you know that Macmini on the desk has a power button at the rear, although you do not even see it. You know you should not sit on that aluminium chair that has been taking sun for hours at the café terrace.

Another argument for the 50mm is not angle of vision, but the fact that an image shot with a 50mm lens projected on a screen of typical size will look "real size" for a member of the audience seated at a typical distance. Or, for still photography, a picture printed in a typical format size, seen at a typical distance, will also look "real size". There is a lot of undefined "typical" here.

The claim of the 50mm should not be taken too strictly. It just tells that the image will appear more or less "natural". But a 35mm, 85mm or 135mm will also look rather "natural".

Edited by Nicolas POISSON
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1 hour ago, Nicolas POISSON said:

.

The claim of the 50mm should not be taken too strictly. It just tells that the image will appear more or less "natural". But a 35mm, 85mm or 135mm will also look rather "natural".

well, I still don't quite get your argument.. so basically, any focal lens is close to the human eye?

This statement of 50mm is close the human eye has been said many times, and I'm only taking it for face value: the fact that looking through a 50mm lens on a full frame camera with one eye, objects in the shots looks more or less the same size as what I see in the other eye. 

But this is not entirely what I am asking here, but the point that people had put this statement in the context of full frame cameras, however Bresson and Ozu had obviously been shooting 3/4-perf but still making the same claim, appears to be very inconsistent. In other words, they are saying a 75mm on a full frame looks closer to what human eye sees. ....

Edited by Wendy Sanders McDonlad
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Yes, it's inconsistent.

The trouble is with the whole concept of "matching human vision". Are you matching field of view? Or degree of magnification of objects? And doesn't that depend on how close you are viewing the image?

Because human vision doesn't have a nice rectangular border around reality. 

For example, IMAX nature/science documentaries tend to use very wide-angle lenses but you are supposed to sit close enough to the screen that a certain percentage falls into your peripheral vision, so you are basically concentrating on the lower center of the image, which is like cropping to a more normal focal length.

The 4-perf 35mm film format was invented before the 8-perf 35mm still format, and yet the early silent cinema cameras started out mainly with a 50mm lens, so I can only assume this was one of the "easier" focal lengths to build and it became the standard for both cinema and stills, though of course in 8-perf 35mm horizontal format, it has a wider field of view. 

At some point, people started to say that the 50mm was the most "natural" focal length for matching human vision and this got taken as gospel by everyone without much thought. It also depends on how close you are getting to the subject -- a 50mm wide shot in 4-perf 35mm can feel a bit long-lens-ish but a tight close-up on a 50mm can still have some distortion due to how close the lens is physically to the face (it's not the focal length creating the distortion, it's the distance that the focal length is causing you to put the camera to get the tight size.)

By the way, once 4-perf 35mm movies started cropping 1.37 Academy (which was already a bit cropped from Silent) to 1.85, the 35mm and 40mm focal lengths started to be used more in its place.

2.66 : 1 Cinerama, with its 144 degree wide-angle perspective, was also touted as being like human vision but this was a very widescreen image projected very large, so a similar experience to IMAX at least on the horizontal plane.

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1 hour ago, David Mullen ASC said:

At some point, people started to say that the 50mm was the most "natural" focal length for matching human vision and this got taken as gospel by everyone without much thought.

That's exactly right. It's a question begging exercise that many people never challenged. I'd say that everyone can safely ignore it. Sometimes, we over-rationalise things, and we just want something to say for the sake of saying something.

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44 minutes ago, Albion Hockney said:

what is the magnification factor from 4 perf 35mm to full frame 35mm still?

 

Horizontally, Super-35 is 24mm wide and Full-Frame / VistaVision is 36mm wide, so that's a 1.5X difference. So the equivalent to a 50mm on Full-Frame is 33.33333... mm in Super-35 and the equivalent of a 50mm on a Super-35 camera is 75mm on a Full-Frame camera.  When you watch old 20's and 30s movies, the master shots of sets do feel a bit compressed as if the camera was outside the room somewhere (which it was) but that kept people in a room looking more similar in size, less receding in size in depth. So in a way, it fed into the star-driven nature of Hollywood cinema where most scenes were shot in medium-shot the actors generally took prominence over the setting.

When CinemaScope first was used, it involved an adapted 50mm lens so early cinematographers touted the greater depth of field of anamorphic when in fact this wasn't true, it just made the 50mm shot twice as wide in view.

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I don't think Ozu ever said he used the 50mm because it matched human vision, he just preferred the way it looked.  Whenever he was asked if he wanted to try another focal-length lens, he said "sure" and after looking at the shot, he would say "yes, the 50mm is better."

Over time, Kurosawa preferred a 75mm or longer... in some ways, I think the flatter perspective of longer focal lengths fit with the Japanese aesthetic established in their art, which did not develop Renaissance-style vanishing point perspective.  They used more flat planes of depth rather than receding diagonals of depth.

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I never know when Hitchcock talked about the 50mm whether he compensated for shooting in VistaVision in the 50's, i.e. did he switch to a 75mm for movies like "Vertigo", "North by Northwest", etc. or did he just get used to the wider view of the 50mm in that format.  Herb Coleman tells the story of supervising a reshoot for "Vertigo", the push-in on Kim Novak's profile in Ernie's Steakhouse when she pauses by the bar where James Stewart sits (sort of his POV of her except that the camera moves) - he said he had to shoot on a 35mm lens because of the tight space and Hitchcock was unhappy about that. But I don't know if Coleman was referring to an actual 35mm lens or the equivalent in VistaVision (a 50mm lens.)

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It's interesting, maybe, to note that the 3-strip Technicolor camera process could not use a focal length wider than 35mm because of the beam-splitter prism. One or two shots in "Gone With the Wind" tried using a wide-angle adapter to get the equivalent of a 25mm but those shots aren't very sharp (I think it was used to get a wide shot of the auction dance that was then rear-projected behind the announcer, and it's one of the worst RP shots in the movie.)

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59 minutes ago, David Mullen ASC said:

I don't think Ozu ever said he used the 50mm because it matched human vision, he just preferred the way it looked.  Whenever he was asked if he wanted to try another focal-length lens, he said "sure" and after looking at the shot, he would say "yes, the 50mm is better."

Over time, Kurosawa preferred a 75mm or longer... in some ways, I think the flatter perspective of longer focal lengths fit with the Japanese aesthetic established in their art, which did not develop Renaissance-style vanishing point perspective.  They used more flat planes of depth rather than receding diagonals of depth.

They have kept this 2D look in  their animation too.. largely , and not gone with the hyper realistic look of Pixar etc .. and I feel still in a lot of drama / commercials .. the lighting is incredibly flat / all at the same stop and without depth, as a style rather than just rubbish lighting ..(well sometimes it is ). even private homes still usually have a large ,round or square fluorescent light in the middle of the ceiling in each room , and thats it .. seldom any other lights unlike the western aesthetic ..Ive often heard from Japanese people that will like a film we have seen , but don't like that its so "dark" and "depressing " .. there is definitely some cultural bent towards "brightness" and seeing every corner of the frame / room  ..

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Not necessarily -- the Japanese-shot scenes in "Tora, Tora, Tora" are generally darker than the American ones, which are somewhat overlit.  Early Japanese color movies were touted for their pastel colors but this was because they preferred underexposing Eastmancolor negative for a "thin" look.  And there's a lot of moody b&w lighting in older Japanese movies.

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Hmm this is interesting, I think it varies of course. But in much of Asian cinema I do notice a tendency toward brighter interiors in various films.

I'm watching "a touch of sin" right now by Jia Zhangke (Chinese film) and noticing the interiors are never dim.

I think you could make the argument American cinema sometimes over dramatizes. I mean our first impulse (atleast mine) for day interior in America is to turn off the lights and use window light, but in the "real" world few people live this way.

 

 

Edited by Albion Hockney
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1 hour ago, David Mullen ASC said:

Not necessarily -- the Japanese-shot scenes in "Tora, Tora, Tora" are generally darker than the American ones, which are somewhat overlit.  Early Japanese color movies were touted for their pastel colors but this was because they preferred underexposing Eastmancolor negative for a "thin" look.  And there's a lot of moody b&w lighting in older Japanese movies.

, .. I guess Im basing it off what I see everyday on TV here , everything is very very flat lighting , and 90% of films being churned out , mostly based on successful day time dramas .. maybe they want to keep the same look .. commercials that obviously has big budgets are the same .. not a shadow in sight in at least 95% of them .. some exceptions but definitely compared to western commercials / films / TV drama,s the lighting is way more flat regardless of the "mood" of the scene .. stills photo advertising too .. 

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47 minutes ago, Albion Hockney said:

Hmm this is interesting, I think it varies of course. But in much of Asian cinema I do notice a tendency toward brighter interiors in various films.

I'm watching "a touch of sin" right now by Jia Zhangke (Chinese film) and noticing the interiors are never dim.

I think you could make the argument American cinema sometimes over dramatizes. I mean our first impulse (atleast mine) for day interior in America is to turn off the lights and use window light, but in the "real" world few people live this way.

 

 

Don't know about run if the mill Chinese productions , the ones that get international release look great , but possibly there is the same thing as here in Japan ..  I mean it might just be not very good lighting , and I guess sometimes thats the case , but I think its more a cultural thing of seeming to just have a preference for "brightness" and a lack of any shadows .. Ive just watched about 15 commercials on TV and not a single one had any shadow on a face , and the whole image was very flatly light ,and bright ( tons of text too but thats a different thing) .. I don't think that would happen in the UK/ Europe / US .. you are going to see a shadow on a face within 15 commercials .. 

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  • 1 year later...

Greetings. 

I have a historical interest and have been a fan of Hitchcock since as long as I can remember so I set out to solve this talk of "50 mm" that Hitch often dropped in conversation with journalists. Hitchcock was from the "Vienna School" of filmmaking (no that's probably not a term ). The same "school" or line of thinking that Murnau and Lang and Michael Curtiz belonged to. It has very old engineering roots. We can date it back to the lte 19th century if we like. Let's not forget that the first film cameras are primitive models of the human head. Friese-Greene built a stereoscopic film camera in around 1888 that was mounted at human eye level.

That "school" followed the thinking that the focal lenght represents the physical size of the watching audience. Shot length = tiny person. Normal and then long lenses representing giants. For all of you that have done work in stereoscopy understand the principle since perspectives and size get's weird when you go out of the normal (around 50) lens zone in stereo 3D.

So to confirm what Hitch was talking about - I ran some of his films through a camera solve software tool that retrieves FOV meta data. Matching that to type of camera used and voilá! Psycho, Rear Window and so on (35mm open gate) is shot 50mm all through. And his VistaVision films are all shot using the 50 mm. He did not switch lenses to match FOV. Field of View was not a priority. His VistaVision films have about 10 more degrees of viewing angle. "Shrinking the equivalent of the human eye" or the other way around was probably not even something he thought about. My guess is he picked this up from the directors and cameramen at Babelsberg/UfA.

Modern films must have looked weird to that era of directors. The camera jumping from dwarf to giant for no story reason other than to fit the camera on set or for it to "look cool". We are actually talking about a part of the language of cinema we don't speak anymore. A set of primes must have been viewed as a box of different sized people. From dwarf to giant. Murnau experimented with the "effect lenses" (everything outside the normal 50) a great deal to create claustrofobia and dreams.

I've chatted with a few optical engineers and the consensus seems to be that 45 mm is spot on the median human being (Angle of View not Field of View). 45 is however still an unusual focal length. I only know of IRIX having a modern 8K lens. Samyang are on their way Q2 2023.

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6 hours ago, Martin Munthe said:

That "school" followed the thinking that the focal lenght represents the physical size of the watching audience. Shot length = tiny person. Normal and then long lenses representing giants. For all of you that have done work in stereoscopy understand the principle since perspectives and size get's weird when you go out of the normal (around 50) lens zone in stereo 3D.

 

As I  understand stereo photography, the inter-lens distance acts like the viewer's inter-occular distance. Close lenses make it seem like the viewer has eyes that are close together and the viewer is small, and widely separated lenses make it feel like the viewer is large.

I'm not so clear on why different angles of view would imply different sizes though. Perhaps a wider lens tends to get used closer, which makes the subject seem larger and therefore the viewer smaller?

 

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Yes, the interocular distance between the eyes helps the brain to judge scale (750 mm being the most common). But the arctan value (distance behind the lens of your eye and it's retina) is also important for judgement of scale in the brain. If you lose an eye you are still going to be able to judge scale by that distance. A camera doesn't have periferal vision. We do. That's where the comparison between eye and camera has to end. We can only extend what a normal lens sees by adding a bigger sensor/bigger negative.

It's really a very simple principle. An eye that is only 8 mm deep belongs to a small person. An eye that is 300 mm deep belongs to a very large person. If you put two 300 mm lenses at a normal interocular distance of 750 mm you will still have the feeling that the world in front of you is a miniature.

The German way of making films was to view the camera as a person (the audience) or a character (pushing dramatic events either through straight POV or the "perspective"). That's why normal lenses was extremely important. You had to have a dramatic reason for turning the audience eyes small or large. You'll find this line of visual thinking in art dating back to medieval times and older. Look at how a classical painter measures reality in front of him with different tools.

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On 9/22/2022 at 1:03 AM, Martin Munthe said:

That "school" followed the thinking that the focal lenght represents the physical size of the watching audience. Shot length = tiny person. Normal and then long lenses representing giants. For all of you that have done work in stereoscopy understand the principle since perspectives and size get's weird when you go out of the normal (around 50) lens zone in stereo 3D.

I'm trying to understand what you wrote.  It's very interesting.  But I can't parse what you mean by "Shot length = tiny person". 

Did you mean short length? Are you saying that the focal length is directly proportional to the physical size of the viewer and that a wide focal length is in proportion with a tiny viewer and a telephoto is in proportion with a larger viewer?  And thus Hitchcock's affinity for 50mm was so that his lens choice was always in proportion with the actual physical size of his audience? 

What would he do for establishing shots?

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On 9/22/2022 at 2:46 PM, Martin Munthe said:

To a German filmmaker in the 1920's this would be the perspective of a small kid. To us it's just "action" and "drama". That's why you would never find this kind of shot in a Hitchcock movie.

private-ryan-wide-angle.jpg

 

That looks like the perspective of a child because the camera is low and looking up at people, not because it's a wide angle.

 

 

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