Longshadow Loc: Audubon, PA, United States

Perception?

R.G. Loc: Scotland

Perception would account for the differences. I think much also depends on what's being viewed - a small print, the viewscreen of the camera, the camera viewfinder or a full screen image on a monitor.

Retired CPO Loc: Travel full time in an RV

Full frame is the same as 35mm and the "standard" lens was 50mm. When I was shooting film with 6X4.5cm medium format the "standard" lens was 80mm. YMMV.

Peterfiore Loc: Where DR goes south

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ELNikkor

Supposedly, 43mm, but your eyes can narrow in on what they want and also, take in wide, out to 24mm.

starlifter Loc: Towson, MD

I have a 45mm prime that's supposed to be "normal".

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

This has been debated here for years. A photo journalism professor at Ohio U. when asked that question at a seminar, said the standard is the 35 mm lens. But, as I have said, it depends on who you ask.
Actually, edge to edge with both eyes open is quite wide, quite wide indeed.

home brewer Loc: Fort Wayne, Indiana

I do not try to capture the actual FOV, but rather the objects that bear interest. I have wrestled with the real FOV for a long time and have concluded that for most views what my eye sees is much wider than what lens is use. Look how many of us take panos or use wide angles for landscapes or may even use a telephoto when shooting down a narrow canyon. For most; it is either art or recording an event.
But my first lens was a 50 mm on a pentex because that is what the photo mags said i should have

Canisdirus

Although the human eye has a focal length of approximately 22 mm, this is misleading because (i) the back of our eyes are curved, (ii) the periphery of our visual field contains progressively less detail than the center, and (iii) the scene we perceive is the combined result of both eyes.

Each eye individually has anywhere from a 120-200° angle of view, depending on how strictly one defines objects as being "seen." Similarly, the dual eye overlap region is around 130° — or nearly as wide as a fisheye lens. However, for evolutionary reasons our extreme peripheral vision is only useful for sensing motion and large-scale objects (such as a lion pouncing from your side). Furthermore, such a wide angle would appear highly distorted and unnatural if it were captured by a camera.

Our central angle of view — around 40-60° — is what most impacts our perception. Subjectively, this would correspond with the angle over which you could recall objects without moving your eyes.
Incidentally, this is close to a 50 mm "normal" focal length lens on a full frame camera (43 mm to be precise).

Source: Cambridgeincolour.com

So a workable central view (eye to camera comparison) equivalent would be ... 43mm.

Longshadow Loc: Audubon, PA, United States

Field of view and something looking 25 feet away in the image when it is 25 feet away in reality are two totally different unrelated scenarios.

Bayou

Jack 13088 Loc: Central NY

I like this analysis. Would the modern version swap a speeding garbage truck for the lion? I am pretty sure the brain has supplies a rapid action non optical zoom.

wmurnahan Loc: Bloomington IN

Looking at a scene, a 50mm on a FF will give you the same view for that part of the view you see with your eyes. In other words holding a 50mm FF camera up in front of you the view on the view screen would fit into the picture. But to get a picture that includes everything you are able to see standing there you need a wide angle.

burkphoto Loc: High Point, NC

Traditionally, a "normal" lens perspective is achieved when you use a focal length equal to or close to the diagonal measurement of the exposed film or sensor area. So around 43mm is correct for 35mm film or digital full frame cameras. In reality, 50mm has been the default, because, well, marketing. However, I like 35mm. Your preference may vary.

Your post hit on something that is an age-old problem with photography... our brains! We have highly evolved bio mechanisms that do white balance, adjust exposure, perform object isolation, and many other tricks that cameras can't do, at least outside of smartphones. The best that can be said for a "normal" lens is that it achieves a similar perspective to what we see with our eyes. Obviously, the field of view is much narrower, but the relative distance between near and far objects is "normal."

TonyBot

... and then, what you *see* and what your eye/brain can comprehend are two different things.

- your eye is pretty basically a 'fisheye' lens. While it lessens with age, most of us can see 160+˚ periferally
- we only 'recognize' about 10˚ to 15˚ of that - which is about equal to a 100mm to 125mm lens.
- by various manufacturers, 40mm, 50mm, and 58mm have all been called 35mm 'standard focal length'

And, using the 'viewing the moon' example, you're only looking at about 1˚ or less - because you are not being distracted (normally) by other objects in view. [The 'apparent' size of the moon as we view it is completely different and very complex subject.]

Personally, I've found that most of my photography is done 24mm to 35mm, with the second most common at about 90mm - but everyone is different.

So, to match the eye, my conclusion is that we would need (in 35mm terms) a 4mm to 1500mm ƒ1.0 lens.
Not exactly a "walk-around"!