Angle of view of the human eye when fixed upon an object.

[Ray]

Hi Peter,
The angle of view of the human eye is very wide indeed if one includes peripheral vision. To confirm this, just focus on any point in a wide scene with your naked eyes (both eyes), then raise your camera's viewfinder to one eye, with your widest lens attached to the camera.

My widest lens is 14mm on full-frame. It's not as wide as my peripheral vision. I would estimate I would need a 12mm lens, or perhaps even wider, to equal my peripheral vision.

The angle of view of a 12mm lens, I believe, is 121 degrees. Can we therefore claim that the angle of view of the human eye is around 120 degrees, or wider? Should we not distinguish between a blurry impression that something is there, (which is all one gets with peripheral vision), and a reasonably in-focus impression that allows us to actually identify what's there?

Where do we draw the line between these two extremes? What criteria do we use in order to determine what amount of clarity is required for objects to fit into our definition of 'the angle of view of the human eye'?

As I mentioned earlier in the thread, for a camera lens to reproduce what the naked eye sees, it would need the FoV of a 1200mm super telephoto lens to match its angle of focus, the FoV of a standard 50mm lens to match its magnification, and the Field of View of an unltra-wide 12mm lens to match the extent of its peripheral vision.

Of course, we're referring here to a fixed gaze, without any voluntary movement of the eyes or the head.  I guess if one were to include maximum movement of the eye balls, but no movement of the head, we could reasonably claim that the angle of view of human vision is around 121 degrees, equivalent to a rectilinear 12mm lens on FF 35mm format.

[Peter McLennan]

One thing I should have added to my experimental conditions: Close one eye when positioning and viewing the targets.

The OP says "Angle of view of the human eye..."

[Ray]

One thing I should have added to my experimental conditions: Close one eye when positioning and viewing the targets.

The OP says "Angle of view of the human eye..."

Quite right, Peter. We lost track of at least part of the original question. My first reaction to the question, 'what is the field of view of one eye', is that it's more than half the field of view of two eyes as a result of some overlap.

The following article from Wikipedia is interesting and addresses the issue. http://en.wikipedia.org/wiki/Binocular_vision

This extract from that article seems to settle the issue, although I'm not sure if I understand precisely what is meant.

...humans have a maximum horizontal field of view of approximately 200 degrees with two eyes, approximately 120 degrees of which makes up the binocular field of view (seen by both eyes) flanked by two uniocular fields (seen by only one eye) of approximately 40 degrees.

What I think they mean is that, whilst the horizontal FoV using both eyes is 200 degrees, only 120 degrees of this is simultaneously seen with both eyes. In other words, the left eye sees an additional 40 degress on the left which is invisible to the right eye, and the right eye sees an additional 40 degrees of the field on the right, which is invisible to the left eye.

If this is correct, we can deduce that the FoV of a single eye is 100 degrees, approximately equivalent to an 18mm lens, FF 35mm format.

It's also interesting that we humans have a very significant feature in common with snakes. We both have our two eyes positioned on the front of our head. 

[Peter McLennan]

If this is correct, we can deduce that the FoV of a single eye is 100 degrees, approximately equivalent to an 18mm lens, FF 35mm format.

I just did a rough test in front of my 27" monitor with an all-white field.  It's easy to see the extent of peripheral vision with a high contrast image.  The FOV appears to be somewhere in the 90-100 degree area.  Horizontally.  Vertical FOV seems about half that.

It's also interesting that we humans have a very significant feature in common with snakes. We both have our two eyes positioned on the front of our head. 

Heh.  When the subject of 3D movies comes up, to the 3D haters who predict its early demise, I say "There's a reason why all animals and insects have two eyes."