What is the human eye equivalence of 35mm format?

Started Jan 7, 2011 | Discussions
JinZM
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What is the human eye equivalence of 35mm format?
Jan 7, 2011

I'm sure someone out there has done this measurement before?

I'm looking for the lens equivalent where a camera will take a picture of roughly what a human eye sees... not wider and not more zoomed heh.

Now I know 24mm is too wide, 28mm is probably too wide.

We don't see in 4:3, we probably see closer to 16:10 or 16:11?

Helen
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 7, 2011

JinZM wrote:

I'm sure someone out there has done this measurement before?

I'm looking for the lens equivalent where a camera will take a picture of roughly what a human eye sees... not wider and not more zoomed heh.

Now I know 24mm is too wide, 28mm is probably too wide.

We don't see in 4:3, we probably see closer to 16:10 or 16:11?

Well, they always used to say (when I took up photography in 1981, anyway) that the typical standard lens for 35mm (a 50mm f1.8 or so) was about equivalent to human eyesight. If I recall, there was an idea that 45mm was a bit nearer to it, actually, but that spec of lens had kind of gone out of fashion during the seventies. All that was for the 3:2 format of 35mm film.

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fsmith
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Re: What is the human eye equivalence of 35mm format?
In reply to Helen, Jan 7, 2011

Mine is about 48mm widesreen.

Fran

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Jorisbass
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 7, 2011

Many people assume 50 mm to be the best approximation, probably because 50 mm lenses are abundant, and are often called "normal" lenses. One is inclined to believe that lens designers chose this focal length because it is the most "natural" one; closest to that of the human eye. It's not that simple actually. It doesn't really take a scientist to see that the diameter of an eye ball is less than 50 mm. So it would be quite impossible to fit a 50 mm focal length in there. Nature is resourceful, but not that resourceful. Folded optics are not part of Mother Nature's design kit. After some research I concluded the human eye to have a focal length of 22.3 mm. With a maximum iris diameter of 7 mm it would mean the maximum aperture is f/3.2. Because our retinas are spherical, you would need an aspherical lens element to achieve the same low level of image distortion. All this would translate to the following specifications:

22.3 mm f/3.2 Aspherical

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John Bean (UK)
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Re: What is the human eye equivalence of 35mm format?
In reply to Jorisbass, Jan 7, 2011

Jorisbass wrote:

22.3 mm f/3.2 Aspherical

Over-specified. The image quality of the lens in the human eye is awful , made usable by a huge amount of real-time processing. There's only a tiny area that comes close to being sharp, the scene is "painted" by scanning (eye movement), refocusing continuously, and remembering the parts of the image not currently in focus.

Add to that movement detection (even in the extreme periphery) that triggers a rapid lock on the detected object and you can understand why its so hard to replicate the human vision system in hardware. It's not about optics, it's about image processing way beyond what can be done in a consumer camera.

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fsmith
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Re: What is the human eye equivalence of 35mm format?
In reply to John Bean (UK), Jan 7, 2011

John Bean (UK) wrote:

Jorisbass wrote:

22.3 mm f/3.2 Aspherical

Over-specified. The image quality of the lens in the human eye is awful , made usable by a huge amount of real-time processing. There's only a tiny area that comes close to being sharp, the scene is "painted" by scanning (eye movement), refocusing continuously, and remembering the parts of the image not currently in focus.

Add to that movement detection (even in the extreme periphery) that triggers a rapid lock on the detected object and you can understand why its so hard to replicate the human vision system in hardware. It's not about optics, it's about image processing way beyond what can be done in a consumer camera.

Very interesting information!

Fran

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tarmo888
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 7, 2011

24mm, full frame, 3:2 format should be 73.7° wide, 53.1° tall and 84.1° diagonal.

The approximate field of view of a human eye is 95° out, 75° down, 60° in, 60° up. About 12–15° temporal and 1.5° below the horizontal is the optic nerve or blind spot which is roughly 7.5° high and 5.5° wide.
http://en.wikipedia.org/wiki/Human_eye#Field_of_view

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Mike Fewster
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Re: What is the human eye equivalence of 35mm format?
In reply to John Bean (UK), Jan 7, 2011

Precisley so John Bean. And also why lots of the discussion about what looks natural in photography is hogwash. Bokeh, DOF, centre/edge sharpness and dynamic range as interpreted in cameras are far from what the eye actually sees. The eye is dynamic, changing as it takes in a scene whereas a photo is fixed.
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Muskokan
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Re: What is the human eye equivalence of 35mm format?
In reply to John Bean (UK), Jan 7, 2011

John Bean (UK) wrote:

Jorisbass wrote:

22.3 mm f/3.2 Aspherical

Over-specified. The image quality of the lens in the human eye is awful , made usable by a huge amount of real-time processing. There's only a tiny area that comes close to being sharp, the scene is "painted" by scanning (eye movement), refocusing continuously, and remembering the parts of the image not currently in focus.

Add to that movement detection (even in the extreme periphery) that triggers a rapid lock on the detected object and you can understand why its so hard to replicate the human vision system in hardware. It's not about optics, it's about image processing way beyond what can be done in a consumer camera.

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John Bean [GMT]

I agree. And I am of the understanding that a 35mm focal length lense on 35mm film format (ie 24mm digital) most closely aproximates the above "human" activity. Which probably explains why those lense focal lengths are as desired/ sought after as they are.
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FJG3
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 7, 2011

I've always heard that 50mm was natural with no zoom and I heard that back in the Canon AE-1 days.

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Jorisbass
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Re: What is the human eye equivalence of 35mm format?
In reply to John Bean (UK), Jan 7, 2011

John Bean (UK) wrote:

Jorisbass wrote:

22.3 mm f/3.2 Aspherical

Over-specified.

But correct. I went through a lot of online literature to get to that number. It's sound. I agree you can't even begin to compare a rectangular flat surface with evenly spread pixels with the human retina, but what was the question again?

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alfredo_tomato
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Re: What is the human eye equivalence of 35mm format?
In reply to Mike Fewster, Jan 7, 2011

I see little value is replicating reality. I'd rather create a version of reality, an editorial about a split second. When you hit that shutter release, you are making a value judgement. Your lens selection is your version of reality. It becomes what the "eye" sees.

I would like a lens that can replicate beer goggles.

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joepix
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 7, 2011

Depends on what I'm looking at.

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John Bean (UK)
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Re: What is the human eye equivalence of 35mm format?
In reply to Jorisbass, Jan 7, 2011

Jorisbass wrote:

John Bean (UK) wrote:

Jorisbass wrote:

22.3 mm f/3.2 Aspherical

Over-specified.

But correct. I went through a lot of online literature to get to that number. It's sound. I agree you can't even begin to compare a rectangular flat surface with evenly spread pixels with the human retina, but what was the question again?

The question was: "What is the human eye equivalence of 35mm format?"

Now perhaps we are interpreting this question differently, but I thought the OP was asking what 35mm (ie full frame) lens produces an image that most closely resembles what we see with the naked eye. That certainly wouldn't be 22.3mm or anywhere close to it.

The answer is found by finding a focal length - on 35mm full frame - that produces a natural-looking relationship of sizes of objects at various distances, "natural perspective" if you like. Yes, I know perspective is not actually anything to do with the lens but the phrase has well-understood meaning that describes what we see. The focal length I'd suggest is about 40mm.

Incidentally, the apparently wider FoV of the human eye is misleading in this context of camera lens equivalence; it seems to imply that the eye is "wide angle" in the camera sense but it's not. Instead what we see is built by scanning with a much narrower FoV, rather like making a wide panorama with multiple camera images made with lens having a much narrower FoV.

Apologies for the over-simplification (I conveniently ignored peripheral vision for example) but it's adequate to answer the OP question - which is not IMO "22.3 mm f/3.2 Aspherical".

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CBuff
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Re: What is the human eye equivalence of 35mm format?
In reply to John Bean (UK), Jan 7, 2011

Wouldn't be simply the diagonal of the sensor/film?

For full-frame 35mm, it would be 43mm (usually, people select a 50mm as a standard lens)
For APS-C (nex-5), 28 mm.
For medium format 6cmx7cm, 92mm (90mm is usual)
For a 4"x5" view camera, 165 mm (150mm is usually selected as the standard lens)

This has to do more with perspective compression, and less to do with angle of view.

Cheers.

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tom
tom
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 7, 2011

I've read that 43 -50 ish is the 35mm focal length for which a scene appears the same as it would visually.

However, I know that when I am walking around and see a scene that I want to photograph, my cameras with a 45 or 50mm lens appears to be too wide. Now I have really bad distance eyesight and my lenses have a lot of correction (which means the IQ drops off very fast as I look through the outside of the lenses.) So my vision tends to be attracted and concentrated to the center of a scene. My 35mm equivalent focal length which has the angle of view and perspective that I see when I'm planning a shot is 100mm. With a lens of that focal length, when I see a scene I want to photograph, I just bring the camera to my eye and shoot. With the wider lenses I have to change my position, which usually screws up the perspective that attracted me to the scene in the first place. Obviously YMMV.

tom

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SparkleHedgehog
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 7, 2011

!!! NERD ALERT !!!

(Interesting though)

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Anthony McCallister
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Re: What is the human eye equivalence of 35mm format?
In reply to JinZM, Jan 8, 2011

50mm is thought as the equivalent of vision from one human eye. 35mm is close to the vision from both eyes at once.

Remember that this is only valid for 35mm film camera sizes or full-frame digital sensor such as the Canon EOS 7D.
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sebboh
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Re: What is the human eye equivalence of 35mm format?
In reply to Anthony McCallister, Jan 8, 2011

Anthony McCallister wrote:

50mm is thought as the equivalent of vision from one human eye. 35mm is close to the vision from both eyes at once.

Remember that this is only valid for 35mm film camera sizes or full-frame digital sensor such as the Canon EOS 7D.
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Mac

actually the canon 7D is not a full frame and in fact has a smaller sensor than the NEX. the canon 5D is a full frame camera.

regarding the human eye, if you really want to replicate it you should shoot a 35mm equivalent and then blur everything outside of the very center and throw out all the color information in the periphery of the scene. if you want to replicate what your brain makes from the info it gets from the eyes you should shoot two binocular super high res video cameras, have the output processed by a super computer (or three) to render the scene in 3d and emphasize features of interest beyond what they actually look like. if you want to replicate rough angle of view, just try a few lenses in the 35mm to 50mm equivalent range and see which feels right to you (different people actually have different abilities to see on the periphery).

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alfredo_tomato
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Re: What is the human eye equivalence of 35mm format?
In reply to sebboh, Jan 8, 2011

When you take a photo you are creating a 2D reality no matter what lens you use. It will never be a perfect replication of what the eye sees.

Technical perfection can be boring. Forget perfection, go for the gut.

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