If the human eye was a lens, what one would it be?

[st599]

you can do a test if you have a FF camera. Stick a zoom on it, look through the VF but keep both eyes open so you get two images superimposing from the open air eye and the vf eye. Then just zoom till the vf eye image matches what you see in the open air eye and bobs your uncle. Check the focal length.

I always keep both eyes open when using a camera. Most of the people I've worked with do the same. Stops you fixating on the screen.

 

[Pookeyhead]

I always close my other eye. I want to fixate on the screen.. that's my frame... and I want to know what's in it.. intimately.

 

[AshleyC]

Doesn't work that, because most camera viewfinders are around 0.75x magnification. They show a "normal" field of view with a "normal" lens, but much smaller, so if you zoom until the objects are the same size, you'll be using a considerably longer focal length than the actual one that gives the same perspective/field of view.

that makes sense. Thought i was onto something there.

 

[John Young]

I always close my other eye. I want to fixate on the screen.. that's my frame... and I want to know what's in it.. intimately.

I am partially blind in one eye so no need to keep that one open when using the camera

 

[andya700]

50mm won't give the field of view on FF the eye does, look at a scene at 50mm through a view finder, then look yourself and you see so much more. I'd say nearer 24mm or even 16mm on 35mm format.

I think that depends very much what you are concentrating on.

 

[droj]

I always keep both eyes open when using a camera.

Maybe it should depend on what TYPE of photography you're doing at any given moment? Street? Still life? As to whether you need that peripheral reference / awareness ...

 

[HoppyUK]

The human eye is somewhere around 24mm f/2.8-11, effective shutter speed typically 1/20sec-ish, but our vision is nothing like any camera. Our eyes and brain work together as 3D-movie makers, constantly scanning the scene in small sections to build up a mental picture, working simultaneously with our other senses. Field of view varies from roughly 2 degrees of critical sharpness, to 180 degrees of 'awareness', with some key points in-between, but nothing that relates directly to the often quoted 50mm lens on full-frame.

IMHO, the best we can say is that a lens between 35-50mm on full-frame, when used for general picture taking of popular subjects, will tend to deliver fairly natural-looking perspective.

 

[Winkyphoto]

When I'm cycling I try to make eye contact with the drivers waiting to come out of side roads so I know they have seen me. When I'm driving I do the same. When I'm flying I don't look out for cyclists at all!

When cycling I deliberately don't make eye contact with drivers. I look elsewhere, keep them in my peripheral vision and simply assume they haven't seen me. By my not making eye contact, they don't know if I have seen them or not and they won't try to guess my move. I also don't want to misunderstand some random wave, or to mistake a blank distracted stare at me for "eye contact" or for them actually seeing me. I just wait or slow and won't move into the intersection or their path, eye contact or not. Misunderstood intentions are far worse than no communication at all.

 

[Winkyphoto]

This is true. Optically, the human eye is rubbish, with only a small area in the centre field of view sharp. The rest of the scene is "constructed" by your brain from memory. Your eye constantly hunts around the scene picking up little details from that small sharp centre zone, so when you look elsewhere, the thing that's no longer in centre is actually blurred, and your brain is simply remembering it. It gives the impression of seamless vision. This is why when you are reading, you get a sense of being disconnected from the world, as your eyes are no longer able to scan or hop around. It's also when you just zone out, and daydream you feel this, as you'll just stare into space, and your eyes are no longer scanning.

Apparently, if you could actually use a human eye for a lens in a camera, it would look something like this..

Colour is restricted to just the central zone. everything that is blurred should also be greyscale.

 

[Pookeyhead]

Colour is restricted to just the central zone. everything that is blurred should also be greyscale.

That's a product f the retina... I was trying to show what the lens of the eye would produce if it could be used as a lens to focus on a sensor.

 

[Jimi-the-fish]

Anybody know what the minimum focussing distance is of the human eye ?

About 5-10cm. Focus on your finger tip as you bring it in towards your eye from arm's length. See when goes out of focus.
(Now try it with both eyes open and aim for your nose - this is a common science experiment in school when teaching about the eye)

J

 

[Brian_of_Bozeat]

When cycling I deliberately don't make eye contact with drivers. I look elsewhere, keep them in my peripheral vision and simply assume they haven't seen me. By my not making eye contact, they don't know if I have seen them or not and they won't try to guess my move. I also don't want to misunderstand some random wave, or to mistake a blank distracted stare at me for "eye contact" or for them actually seeing me. I just wait or slow and won't move into the intersection or their path, eye contact or not. Misunderstood intentions are far worse than no communication at all.

This is taught by the Institute of advanced motorists and I was also taught this when I did my cycling proficiency in the 1970s. I have been cycling for 40 years and driving for 30 on British roads and covered many thousands of miles and it has always served me well both in the car and on the bike. I don't think I will be trying your method, but thanks. and good luck!