Focal length most similar to real world perspective.

[J_Allen]

You often read about the focal length of 40-50mm being the closest the human eye perspective, and I think this refers mainly to angle of view. When I think about a focal length most similar our eyes, I think of the distance to the object. If I put the viewfinder to my eye, or LCD near my face and then compare it to my subject, the subject should appear the same distance away- not farther and not closer. I think this is more representative of human vision, and in my experience it is somewhere around 60-62mm. I have only tried this with subjects that are relatively close- like 10-15 feet away and have not tried it in open areas but I think it would be similar. I curious what other people's thoughts are on this. If the angle of view is similar but the subject is smaller and farther away, this to me does not resemble human vision.

 

[Leonard Migliore]

You often read about the focal length of 40-50mm being the closest the human eye perspective, and I think this refers mainly to angle of view. When I think about a focal length most similar our eyes, I think of the distance to the object. If I put the viewfinder to my eye, or LCD near my face and then compare it to my subject, the subject should appear the same distance away- not farther and not closer. I think this is more representative of human vision, and in my experience it is somewhere around 60-62mm. I have only tried this with subjects that are relatively close- like 10-15 feet away and have not tried it in open areas but I think it would be similar. I curious what other people's thoughts are on this. If the angle of view is similar but the subject is smaller and farther away, this to me does not resemble human vision.

The effect you're describing is viewfinder magnification. It doesn't affect the finished image at all. With SLR's, the magnification is the ratio between the focal length of the eyepiece and the focal length of the taking lens. The standard for viewfinder magnification was the apparent image size with a 50mm lens. Most viewfinders, especially with APS-C cameras, had a magnification less than 1. My D750 had a magnification of 0.7, which means it would give you a 1:1 view with a lens set to 71mm.

The same standard seems to be used for mirrorless cameras. My Zfc produces a life-sized viewfinder image with the lens set around 50mm. It's listed as having a viewfinder magnification of 1.02X but, of course, 50mm is equivalent to 75mm with APS-C.

I see no way to compare the size of an image on an LCD to what you see when viewing that object directly.

 

[Gato Amarillo]

What I've heard and read several times over the years:

The idea of the 'normal' focal length being equal to the diagonal of the film comes from the anatomy of the human eye, where the measure across the total imaging area is about the same as the focal length of the lens. That's about 42mm for 35mm film or a full frame digital sensor.

However, the eye only sees sharply over a smaller area and when we concentrate on a single subject what we see and are aware of is closer to the view of an 85mm lens on 35mm. At the other end, the eye is usually in motion and the brain is keeping track of the scan, so the area we are visually aware of is more like a 24mm lens.

Just for what it's worth.

Gato

 

[Erik Baumgartner]

For me it’s around 23mm APS-C (35mm FF equiv.).

If I see a potential shot and raise a 23mm APS-C lens to my eye, that’s pretty much what I get. A 27mm requires a step back, 18mm requires a step forward.

 

[Planterz]

However, the eye only sees sharply over a smaller area and when we concentrate on a single subject what we see and are aware of is closer to the view of an 85mm lens on 35mm. At the other end, the eye is usually in motion and the brain is keeping track of the scan, so the area we are visually aware of is more like a 24mm lens.

Yeah, that's the "problem" with quantifying what the human eye sees, combined with what the brain processes. You might think your eyes scan over things smoothly, but they don't. Watch someone read a book sometime. They think their eyes are smoothly moving across the page, but in reality they're darting from point to point.

You could also, for example, look at a person's face. You see their face, you recognize the assemblage of parts as a whole as a face, perhaps you recognize this face as someone you know. But you're not looking at their nose, or ears, or chin. Look at their eyes to make conversation and you don't notice the zit on their chin. Notice the zit, and now you can't look away and you have no memory of what their ears actually look like. There's no additional magnification, and focus doesn't makes us lose our peripheral vision, but our brain focuses on details that "narrow" our vision.

40-50mm might be the approximate magnification of what we "see", but it loses the peripheral that our eyes still have and doesn't account for the hyper-focusing on details that our brain does without us realizing.

 

[ishwanu]

IMO there's no meaningful answer, though it's always a popular and recurring forum topic.

 

[jalywol]

For me, the focal length that I "see" relatively close to medium distance subjects at seems to be around 70mm.

Way back in the day, when I got my first SLR (a Pentax MX), it came with the "normal" 50mm lens. I struggled with that, as it just never "saw" the subjects the way I did.

Many years later, when I started working with digital cameras, I had more of an opportunity to experiment with different lenses, and the field of view that most closely approached my actual one turned out to be about 70mm. (Not for wide landscape situations; for that the 24mm range works fine).

So, I think this is one of those areas that's going to vary per individual...

-J

 

[Michael Fryd]

You often read about the focal length of 40-50mm being the closest the human eye perspective, and I think this refers mainly to angle of view. When I think about a focal length most similar our eyes, I think of the distance to the object. If I put the viewfinder to my eye, or LCD near my face and then compare it to my subject, the subject should appear the same distance away- not farther and not closer. I think this is more representative of human vision, and in my experience it is somewhere around 60-62mm. I have only tried this with subjects that are relatively close- like 10-15 feet away and have not tried it in open areas but I think it would be similar. I curious what other people's thoughts are on this. If the angle of view is similar but the subject is smaller and farther away, this to me does not resemble human vision.

The angle of view that matches the human eye depends on print size and viewing distance.

If your print fills about 46° of your eye's filed of view, then something around 50mm on a full frame will look natural.

If you have a very wide angle lens, then the print will look natural when it is large enough, and close enough, to fill a wide portion of your field of view.

 

[gary0319]

After some non-scientific trials, I found that a 50mm FOV most closely approximates the view that is framed by my eyeglasses and is therefore most natural for me.

 

[MoreorLess]

You often read about the focal length of 40-50mm being the closest the human eye perspective, and I think this refers mainly to angle of view. When I think about a focal length most similar our eyes, I think of the distance to the object. If I put the viewfinder to my eye, or LCD near my face and then compare it to my subject, the subject should appear the same distance away- not farther and not closer. I think this is more representative of human vision, and in my experience it is somewhere around 60-62mm. I have only tried this with subjects that are relatively close- like 10-15 feet away and have not tried it in open areas but I think it would be similar. I curious what other people's thoughts are on this. If the angle of view is similar but the subject is smaller and farther away, this to me does not resemble human vision.

Its referring to how perspective if rendered, that is objects at different distances appearing the same size relative to each other as they would for humans. Thats what makes it "easy" to compose for as you can judge composition by eye more easily.

Our actual angle of view is a lot wider at 40-50mm although its obviously less "exact" than a lens/sensor/film with a hard edge to it.

 

[Tom Axford]

Here is a brief extract from the Leica Manual of 1937 that answers your question:

 

[OpticsEngineer]

For better or worse, 50 mm on 35 film mm became accepted in the optical scientist/engineering world, I think by virtue of it coming from Leica, and if it was wrong, it wasn't very far wrong. Although suspiciously 50 mm lenses are kind of in a sweet spot of being lenses that are easy to make. Anyway, no other engineers have ever argued with me about using 50 mm and it gets referenced in various lens design textbooks quite a bit.

 

[Bobapingu]

You often read about the focal length of 40-50mm being the closest the human eye perspective, and I think this refers mainly to angle of view.

Quite right, this is often said. However, I'm not sure what it really means. Is it referring to an average person, looking at an average scene at comfortable viewing distance? I'm here looking at cluttered opposite wall. I'm not looking at anything in particular. I seem to using only peripheral vison, so the field of view is quite wide. Then, if I look out the window at a distant object, I'm using only central vision. The field of view is quite narrow. Peripheral vison is basically ignored. Then there's that phenomenon that most can relate to, where when using a particular prime for a long time, you start to see the world that way. The same would happen for those that grew up on the wide open plains as against those that grew up reading books indoors. So, what's more natural? I don't know. Perhaps the key here is perspective. It might have nothing to do with the geometry of the human eye but with what humans find more aesthetically pleasing. Artists here would know all about this. Please jump in. They would know what perspective is the more pleasing. That would be a function both FL and subject distance, I guess.

 

[Tom Axford]

You often read about the focal length of 40-50mm being the closest the human eye perspective, and I think this refers mainly to angle of view.

Yes, it does refer to angle of view. It is considered to be the angle of view that is usually chosen as that preferred by someone viewing the image; i.e. a viewing distance equal to the length of the image diagonal or a little more.

 

[Ysarex]

You often read about the focal length of 40-50mm being the closest the human eye perspective, and I think this refers mainly to angle of view. When I think about a focal length most similar our eyes, I think of the distance to the object. If I put the viewfinder to my eye, or LCD near my face and then compare it to my subject, the subject should appear the same distance away- not farther and not closer. I think this is more representative of human vision, and in my experience it is somewhere around 60-62mm. I have only tried this with subjects that are relatively close- like 10-15 feet away and have not tried it in open areas but I think it would be similar. I curious what other people's thoughts are on this. If the angle of view is similar but the subject is smaller and farther away, this to me does not resemble human vision.

Michael noted it above and Tom noted it twice above; the size and viewing distance of the image (print) has to be taken into consideration. We look at photos in many different settings using everything from electronic displays to framed prints -- so complicated. I am only aware of one empirical study of the subject. Leslie Strobel taught photography and had an ideal test circumstance -- the campus art gallery and grad students. So they placed subtle marks on the floor and the grad students who were probably gallery monitors anyway recorded how far back people naturally chose to stand to view a print. After a large enough sample was recorded the answer was approx. twice the long side of the print. So a 16 x 20 inch print hung on the wall and people naturally tended to stand back approx. 40 inches to view it. Now you can do the math, but for what it's worth it only applies to a print hung on the wall and most of us view photos differently. The lens that will record perspective in the original scene that matches what the print viewer sees is going to be longer than 50mm on a 35mm camera, around 70mm.

 

[yardcoyote]

The "common knowledge" answer to this is between 40 and 45mm on film or FF. Pentax famously made a 43mm that it claimed was a true normal.

I actually tested this on film by making images from a marked spot and then printing them and viewing them from the same place-- not very scientific, but a good rough and ready empirical test that factors out the effect of the viewfinder. The accepted wisdom is bang on correct for me. 40mm is definitely a slight wide angle, and 50mm very clearly a distinct telephoto from my perspective. So my normal lens will be something like 43 or 45.

I don't know how useful this actually was or is, but it was fun to do and answered the question to my personal satisfaction. I also have no idea how much my results might apply to anybody else.

--
Instagram: @yardcoyote

 

[Howard V]

When my 50mm Nikkor was on either of my 35mm Nikon film SLRs, I could view with both eyes open, and the right eye viewfinder image matched the left eye. That seemed the ideal focal length to me, at the time. Now I’ve learned that the viewfinder magnification played a role in that, and have no standard to replace it, except that I like 28mm on APS-C Nikons. That calculates as 42mm effective.

 

[Dennis]

You often read about the focal length of 40-50mm being the closest the human eye perspective

If you're standing 50' away from something and shoot it with a 24mm lens, 50mm lens and 100mm lens, the perspective is unchanged. You can tell from the relative sizes of objects in the image (assuming you have some familiarity with it) where the photographer stood when the picture was taken.

, and I think this refers mainly to angle of view.

There's another school of thought on this. If you take a picture with a lens whose FL is equal to the diagonal of the sensor, then print the image, then stand where the photographer stood and hold the image at a viewing distance equal to the diagonal of the print (a "standard viewing distance" according to some) then the print "blends" into the scene in front of you. In other words, viewing the print at a standard viewing distance is just like viewing the scene. Change any of those assumptions (like print size or viewing distance) and you change the FL needed to get that same effect. Still, something around 40-50 looks "natural" to me. (I prefer 40mm).

When I think about a focal length most similar our eyes, I think of the distance to the object. If I put the viewfinder to my eye, or LCD near my face and then compare it to my subject, the subject should appear the same distance away- not farther and not closer.

Put the same lens on two different cameras and that changes, depending on the viewfinders.

I think this is more representative of human vision, and in my experience it is somewhere around 60-62mm.

I think that's only relevant if, for some reason, you rally care about matching magnification of what the eye sees in the viewfinder (of a particular camera) and not in the final result.

 

[Gato Amarillo]

I learned photography before zooms became popular. I started with a twin-lens reflex, so didn't have a choice of lens until I got my first 35mm.

When I got my first SLR the 50 was ok, but I was really hooked the first time I looked through an 85mm. Next came a 35, and the 50 was pretty much on the shelf after that. When I started working alongside experienced news photographers I realized they favored a 24, and I quickly adapted.

The standard news kit in those days was 24, 85, 180, and 300, with the 24 and 180 the most used. The 85 was for indoor portraits, the 300 for when you couldn't get close enough at a news event or sports. The wide 24 and the tighter 180 seemed to "grab" the readers better in a page 1 photo on the newsstand, compared to the standard 50. A few of the bolder types chose a 20 over the 24.

At least that's how it was with the photographers I knew in Dallas back in the day.

Gato

 

[tex]

Extend the index fingers of both hands and bring you hands up to the height of your cheeks with the index fingers pointing up, about at shoulder width.

back your hands up to around your ears (still at shoulder width) and then bring them forward at the same time slowly while fixing your vision straight ahead. When you can see your fingers then that's the extent of your peripheral vision and so your angle of view.

it varies a lot with different people, but for those with "normal" vision it's a hugely wide arc, wider than any lens but a fisheye.

With respect to "normal" lenses, they tend to give a "natural" view of the central part of this wider arc---natural in that it's not distorted in any way. But obviously it cuts off a very large part of what we can "normally" see.