Human Eye Focal Length

boojum

boojum

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I just ran across this YouTube video of the approximate focal length of the human eye. What got my interest was that in 35mm format, as shown in the Ur-Leica, a 42m lens best approximates best what the human eye sees. And what makes this important in the HB arena is that the current "standard lens" for the X2D is the XCD 55V. This lens translates to a 35mm format 43mm lens. Close enough for government work. The video covers more than that and here is the link for those interested:
 
40 for me was no go. 35 is. And humans are different. So, here is no single focal length to represent us all. Winogrand was finding 21 close to his vision. And so do I. I never get used to 24, it was just odd to frame. But 21, I don't need VF much, because it is how wide I could see.

But. If you shoot with single focal length for couple of years, you will start to frame instantly. I did 35 mm on Bessa, Leica and framing was accurate in one frame to take few seconds to take situations.
 
When I was at college it was said the 35mm was the nearest to the human eye. But there was a practical side to it because if 35mm is slightly too wide for equivalency it's easier to zoom in using your feet rather than back up especially in a crowd. Perhaps that's why Winogrand liked wider lenses yet the photos often don't look 'wide angle', he gradually moved in on his subjects (sounds a bit creepy but you know..). But it's true that you get used to what focal length you've got on the camera and that is how photographs form in the mind before holding the camera to your eye for final composition. And preferences can change over the years, it took me twenty years to go from 35mm to 28mm as my 'standard' lens, and another twenty to go from 28mm to 50mm, I don't know what will be next.
 
So I've been told. Over and over again. I still prefer my 50s. Perhaps it's because I wear glasses? :eek:

I'll have a 28 & short tele (either a 90 or 105, depending) along just in case but 99% of my photos will be with that 50 & a two foot zoom.
 
At work so can't watch the video. But depends on what you're asking. FOV of humans is close to 180degrees. Sharp focus area is quite small. But the pespective we see things is close to true normal in camera terms (42mm on 24x35 frame, 80mm on 6x6, so forth). So for true human perspective you would want swiveling lense, like horizon or similar, with normal focal lenght lens. Then again, I'm happy with 35mm and call it close enough, or 50mm :D
 
I didn't watch the video but 42mm looks pretty good to me. The 28/2 (135 equiv. 42mm) pre-aspherical Voigtlander Ultron has become my most used lens on the X-Pro2. Does it match my eyes? Not really. It's just a do-it-all lens. And a very nice one at that.
 
Pentax is here to help you out. The 43mm f1.9 Limited was at least partially designed because it was so close to the human eye. There's even a rangefinder version of this lens if you can't be bothered to pick up a K-mount camera ;)
 
Respectfully disagree for two reasons. 43mm is a so-called "normal" focal length because of its relationship to the diagonal of 35mm film. It has nothing to do with the field of human vision.

I'd say, shooting from the hip, that the human eye is like a 17mm lens [Edit: after asking Google, "what's the angle of view of a 17mm lens?" I would change this to 10mm or thereabouts] with a zoom feature for whatever has your attention. That is to say, the human eye as a lens system produces an image that your optic nerve can pick up, but it's your mind that decides what's important. So when you're reading, just the macula is involved, which is the central 2-3mm of cells in you optic nerve - kind of like a 100mm macro lens -- everything on the periphery drops away. However, when you are looking at a landscape and something moving at the periphery of your vision "captures" your attention it is waaaay out there in focal length terms. Something much more akin to the edges of a 17mm lens.

I approach this thinking about what your eyes evolved for: finding food (detail) and avoiding predators (wide). Those whose eyes weren't up to those two challenges had lives that were nasty, brutish, and short.

[Edit pace Hobbes' Leviathan, all lives were nasty brutish and short in the dim and distant past, at least up to a point. But nasti-er, more brutish and short-er for those whose eyes functioned like a 43 mm lens, which is what you'd get in the late stages of glaucoma.]
 
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Having been through the video, the speaker is pretty nuanced in terms of the terms of his presentation. You could quibble with wanting to "carve out" a rectangular field of view from what is essentially a curved plane. Interesting enough to watch, though. There are a couple of moves he makes that I'd quibble with, but he is having fun with it, so . . .

I'd just point out that the "angle of view of the human eye" and "what do we perceive as a normal focal length from a perspective perspective" are really two different questions.
 
I've always heard and read that the actual human eye FL runs about 22-26mm.
The area of the average retina is about 1000 sq. mm.
The area of a 24x36 film/sensor is 864 sq. mm.
The horizontal angle of view of a single human eye is about 120º. Two eyes together is nominally 180º. The angle view of the macula is variously described as being 1/2 of 1º, 1º, 3º, or 6º.
Therefore, for the best simulation of the total of what both our eyes see, a full frame fisheye is probably the closest we have on cameras.
For simulation of ONLY what one macula sees in detail, a 1000mm tele might be close.
So there's your two normal lenses: Fisheye and 1000mm.
All this ignores that what we're doing in conventional photography is placing images of objects into frames, and for that we have 50mm, 40mm, 35mm, 28mm, and all the rest.
 
Myrrys.eu said:
My first ever camera and true photographic love to this day is Olympus 35RC and it just happens to have a 42mm lens
Click to expand...
You could be over romanticising it but the 35RC is a beautiful camera in many ways and the lens is like a slightly relaxed 50 or a slightly tight 35, so good either way. Let us not forget to mention at every opportunity the quality of the lens and the cameras features!
 
boojum said:
I just ran across this YouTube video of the approximate focal length of the human eye. What got my interest was that in 35mm format, as shown in the Ur-Leica, a 42m lens best approximates best what the human eye sees. And what makes this important in the HB arena is that the current "standard lens" for the X2D is the XCD 55V. This lens translates to a 35mm format 43mm lens. Close enough for government work. The video covers more than that and here is the link for those interested:
Click to expand...

None of the approximations ever made any sense to me, since we see with a pair of eyes. In the room i'm in at the moment, looking straight ahead is a view i'd be hard-pressed to cover with a 15mm.....
 
This is very interesting, but we see what we can see. I wouldn't worry about it. I can tell that when I use a 50mm lens, I see more focused an area that is less wide than what I can see without the camera. My iPhone shows me a wide angle view of the world around me. As long as I like the view seen with a lens, I am OK with it.
 
Don't humans "see via their brains"? The "sensor" is in our brain. Right?
Do we all have identical brain sensors?
Hm.
 
Cameras have rectangular or square frames. Human vision is frameless. I know. That's a "duh". Perhaps the closest to the human eye is the Widelux, the Noblex or similar cameras. But, so what? The point is that frames are a compositional artifices and the idea focal length is whatever the photographer chooses to create the composition. Everything else is an academic exercise.
 
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