What is the Focal Length of the Human Eye?

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The human eye, often likened to a camera, offers unique insights into the art and science of cinematography. By examining the structure and function of the eye, we can gain a deeper appreciation of visual perception and camera technology.
This video explores how the focal length of the human eye correlates with cinematography. We dive into aspects like the area of the retina, field of view, binocular vision, and the distribution of photoreceptors. Enjoy!

[@wolfcrow]

What is the Resolution of the Human Eye for Cinema? kzbin.info/www/bejne/h4evgpuMfqyqmqs

[@androwmurphy3108]

What is the song in the background please ?

[@TheArtofKAS]

Once again. Is the answer to all questions 42 😂👀👀

[@Gabriel-it5jy]

❤

[@reludennis]

Ha ha....after millions of years of waiting....the answer is: 42

[@flyingo]

Yes! And.. don’t panic.

[@dietmarfinster3176]

The diagonal of my towel. Always ready.

[@jd5787]

Thanks for the fish!

[@TheArtist441]

After shooting with 35mm, 50mm and 85mm lenses in my pursuit of finding my perfect focal length for my photography, I had some interesting findings. =50mm seems formal and more strict. And then I found 40mm. 40mm had a true, genuine, real, even a humble feel. I realized that there was something special about 40mm, and seeing this video it makes sense to me why!

[@AngryApple]

an this is why I just love my Ricoh GR3X. I just dont want another camera or focal length

[@lol-bg4wh]

U doing to much

[@area51pictures]

Finally! A reasonable, educated and intelligent answer to an often extremely foolishly answered question

[@Sonnell]

I think this answer is silly. And there is no such thing as the focal length of the human eye, especially not in connection to cameras. This completely disregards the image size we are looking at and the distance of it. And that human vision is very different anyways.

[@larryzapata2614]

Pentax would agree with you. They created the FA 43mm F1.9 limited back in the 1990's

[@RyougiVector]

It turns out the focal length of 43mm was a byproduct of lens design constraints Pentax imposed for the Three Amigos rather than to fit this fact that 43mm on a 135 format sensor corresponds to 1 radian. It's why the other two lenses have 77mm and 31mm as their focal lengths.

[@j.f.7509]

Nice video! Just one clarification: Oskar Barnack never designed lenses. It was Max Berek the genius behind the Leica glass. The 42mm for the UR-Leica was a microscope lens (Summar) that was chosen because it was already available for Barnack's proof of concept. However, they needed a much better lens for the enlargements that were needed to compete with the quality of the prints that were on the market then. The 50mm was easier to design and there were already many examples around to get inspiration from.

[@wolfcrow]

Max Berek is credited in the video.

[@OttosTheName]

This makes so much more sense to me. I've always felt like 28mm or wider is pretty decent at capturing an entire scene like a landscape sort of as I see it. And 50mm is closer to focusing on a detail or a face. Just saying 'this is the focal length' always seemed very silly to me. Thanks for the very detailed video, very educational.

[@wolfcrow]

You’re welcome!

[@AdrianBacon]

This is why my every day lens on a full frame camera is a 40mm and a 24mm on APS-C. When I put the camera up to my eye, what I see in the frame is pretty close to my generalized perception where I'm just taking in the world writ large without focusing or paying attention to any one thing. If I'm focusing or paying attention to something, closer to 70mm is about right, and 150+ feels like tunnel vision.

[@BadGuyDennis]

I always argue we should not compare photography and human vision in terms of field of view / view angles, but we should compared in terms of perspective, i.e. how we perceive the distance / spacial relationships between the subject and it background surrounding it. That way what we called "normal" lens projects the prospective closest to how we understand the depth relationship in real world is making more sense to me.

[@nickin]

I make shows in large spaces round the world we often shoot reference images for the team who arnt on the early trips. The perspective relationship of buildings we might project on is extremely important for designing any sets etc. in large spaces with lots of depth the apparent size of objects always feels most natural to me when shooting near 50mm this really became clear when we were projecting on the Washington monument as there is so much space. When we used 48mm in camera and software our visualisations matched the real world relationships of scale. I’ve never really understood the focus on fov as our perception is so based on building images from many samples and who can really feel the edge of their vision without really focusing on it. How big things are in relationship to each other is how we really feel our place in the world.

[@krectus]

yeah I was waiting for this video to get to the perspective part and it just didn't, completely missed a major part of why we consider these normal human vision lenses.

[@tor2919]

Thank you, haha I threw myself into writing a comment about perspective and then found you comment. Perspective, a natural compression of objects relationship to each other in a 3D space is way more important than field of view for a natural look.

[@Sea0fTime]

Out of the dozens of sources I've seen cover this topic this is by far the best. The effect of mental focus on your subject and it's effect on apparent subject size is typically ignored completely when covering this topic. I especially liked how you discussed there being one focal length that's closer to the human eye when you are broadly taking in a scene versus a scene where you are mentally focused on a subject, that has an immense impact on the apparent equivalent lens focal length. When I'm not focusing on anything in particular my field of vision is something close to around 18mm but the size of objects within that field of vision appear closer to how a lens around 60mm would make them appear. This simultaneous dual focal length is just not something a camera with a single lens and no brain can recreate so it makes sense to pick a focal range that is a good balance of fov and magnification and call lenses that fall within that range as "normal". Personal preference of fov vs magnification is going to affect what people think is more normal for them individually. I tend to lean toward fov as being more important when thinking about making a scene look more normal but I don't necessarily want subjects to appear too small in the frame so I like focal lengths in the 28-35mm range for representing normal, 50mm cuts off way to much of my peripheral vision to appear normal, even though subject size is closer to normal for me. If I were to average my fov and magnification preference I get 40mm as my average normal which is very close to the original Leica you mentioned. Konica made an excellent Hexanon 40mm f1.8 lens but I'm not sure if there are others.

[@alessandromussa]

I always thought that the "normal" focal lenght was something around 43mm because the diagonal of a full frame sensor is 43.27mm. But this video explains there is more about it. Very interesting, thank You!!

[@seanhuxley3348]

In author Douglas Adams’s popular 1979 science-fiction novel The Hitchhiker’s Guide to the Galaxy, toward the end of the book, the supercomputer Deep Thought reveals that the answer to the “Great Question” of “Life, the Universe and Everything” is “forty-two.”

[@shaunla.1098]

In 1914, the Multi-Speed Company in the United States had a 35mm camera called the Simplex Multi-Exposure which carried a Bausch & Lomb 50 mm f/3.5 Tessar lens. While in Germany Oskar, reportedly had no clue that such a small-format camera was being advertised in the United States (the Tourist Multiple of Herbert & Huesgen premiered in 1914 to a U.S. population as well), 10 or 11 years before his accomplishments with Leica. Therefore, I don't know if back then, could the 50mm lens be a starting point or was the 42mm lens a debatable counter point? Excellent content & insight that you expressed here. I enjoyed it.

[@PaulKretzEng]

Once upon a time I heard that "normal" is the diagonal of the sensor\film. So *for full frame it's 43mm* =) Multiply\divide by crop-factor to calculate it for bigger\smaller sensor\film formats. That easy.

[@joachimrichter4765]

The diagonal is important because it is not all about the angle of view but mainly you could consider the relation between foreground and background. A diagonal takes this into account, maybe. I am not an expert but this was my interpretation when I thought about it.

[@Zobeid]

Surveying the landscape of vintage photographic (not cinema) film cameras, I noticed an oddity. 50mm was considered the standard normal lens among 35mm film (i.e. small format, 135 Format) rangefinders and SLRs with interchangeable lenses. As soon as you moved outside of that category, and you start considering medium format cameras, and even fixed-lens small format cameras, the 50mm focal length fixation largely dissipates. A lot of them had 35mm or 40mm equivalent lenses. I mean for example, consider how many Olympus Trip cameras were produced with 40mm lenses! Personally, one of my most-used prime lenses is 28mm on my APS-C camera bodies, which, taking account of the crop factor, works out to… hmm… 42mm! (OK, 42.8mm if you want to really split hairs.)

[@canderson1955]

I am using a Viltrox 27mm on my Fuji so 40.5mm on FF. It seems pretty accurate and I love using it.

[@dirkc4612]

Leica has (had) a 40mm lens for the Leica rangefinders (Leica M range). It is the Summicron 40C F2.0 manufactured in the 70s. It still is fully functtional and it performs wonderful on the latest diigital rangefinders. I love this focal length because it is a very practical compromise as a one lens solution. You explained perfectly that depending on we use our eyes our natural or better preferred focal length varies between 24 and 160mm. So there is not 1 natural focal length. Everyone has a different favorite, usually 35, 40 or 50 mm. Sometimes 28 or 75 mm.

[@michaelberg507]

Years ago, when I worked in a camera shop, we used to reference 42-43mm as an "eyeball" normal, meaning the most used "normal" lenses (35mm and 50mm) were somewhere around 8mm wider or 7mm longer than that benchmark. I am currently shooting with a 2/50mm Zeiss Biogon on my rangefinder, which feels that it is really 47mm-48mm - a little wide from what I expected when compared to an old 50mm Dual Range Summicron. In use, I feel a little less constrained than I did with the 50mm. Great video - thanks!

[@gamebuster800]

I generally find the argument kinda weird to start with because a photo is nothing to a human until it is observed. How is the user going to observe an image? That matters a lot to how it, and the focal length used, is perceived. Imagine looking at a small print, 4x6 (10x15). On that size, a normal or telephoto shot looks more "real" to me. It is like having a tiny window to look through, where you only see a small FOV of the world through that window. At the same time, now imagine sitting in a huge cinema with a screen surrounding your vision. A telephoto image would look weird, while a wide angle image might look perfectly normal to me. The "normal" focal length should be one which would match the FOV of the final image. Obviously you can ignore that rule and do whatever you want, but i feel like if you want to match "a normal look", you should try to match the FOV of the image how it will be presented.

[@lucianoag999]

I agree. Natural focal length = picture distance / picture width x sensor width. I explain it in a comment.

[@Orefield177]

Yes exactly, this is my understanding as well. To take your example even further, imagine stretching the cinema screen all around you so that you are sitting inside a "cinema ball". Or to take a more normal example, imagine watching a scene in vr glasses. This is more similar to what we see with our eyes. Except in the real world you also have actual depth. Asking what focal length our eyes have in the way this video does becomes kind of strange. Not just because our eyes and brain are different to a camera. But mainly because we are watching a 360° world. In a similar way it would be strange to ask: What is a "normal" focal length of a 360-camera. You could (I think) theoretically (not practically) use any focal length you want for the lenses in a 360-camera and the resulting stitched image would have the same "depth compression" anyway. Simply because it is a 360° image viewed from "inside". But maybe I'm just complicating things. The main thing is, exactly as you've said, that there is no objective "normal" focal length. It depends on the size of the image and the viewing distance.

[@ahothabeth]

You focus, pun intended, on the field of view: another thing to consider is the perspective or depth of field i.e. what is the relationship amongst objects in terms of their perceived distance one from another.

[@barrygormley]

This to me is the only thing that's relevant when comparing to what the eye actually sees. Weather the distance is compressed or extended. The lens that matches this closest is closest to reality. Field of view is secondary to representing reality in a frame as seen by the human eye.

[@lucianoag999]

Look at my definition in my comment above. That is what you are looking for.

[@krectus]

yeah this video completely misses the main point, that being perspective. That's really why these focal lengths are considered so close to our own eyes.

[@samjesberg]

I watched the whole video, and I couldn't really understand it. Isn't there a big difference between "field of view" and "perspective" ?? I thought around the 50mm mark was the perspective of the human eye, obviously not the FOV. You can take a picture of somebody face at 15mm and 50mm, having the exact same FOV (taking the shot closer with the 15mm, and moving further back with the 50mm). Both pictures will have the same field of view, but the perspective will be radically different. Maybe I'm missing something here??? I found a good quote from a photography forum about this: "A 25mm lens at 10ft will give you the same field of view as a 50mm at 20ft, but the perspective will be different. The 25mm will give you a much wider view of the background behind the subject, whereas the 50mm will tend to slightly compress the foreground and background. If you were to then change to a 100mm lens at 40ft, you would again have the same field of view, but the perspective would change, and the backgrounds would be even more compressed"

[@user-eh8jv2em2o]

There's no such thing as the "perspective of the human eye." By moving further back with a 50mm lens, you don't achieve the same field of view (FOV) as with a 15mm lens. While you might capture the same objects, the shift in position inherently alters the composition. You can't change the FOV of the lens simply by moving. What you're overlooking is that the lens doesn't directly affect perspective; rather, it influences the cropping of what is seen through it. A lens serves as a window through which the camera perceives the world, and different focal lengths change the size of that window without altering the content seen inside. With a 15mm lens, you could achieve the same perspective and field of view as a 50mm lens shot from the same spot by simply performing a centered crop of the picture afterward. The primary noticeable difference would be the blurriness of the background.

[@picturemaker]

I've been waiting years for this video. Thank you.

[@wolfcrow]

You're very welcome!

[@DrVishalT]

One of the best videos I've seen lately. Awesome work. I'm a doctor and I love photography. It was a double treat for me.!

[@lecolintube]

Wow, thank again, that’s wonderful! (And an amazing video! 🤩🙌). Something that often feels a little overlooked in these conversations is compression and distortion. I definitely can’t reproduce the bokeh & separation of a subject in my eye, say that a 160mm lens can (or even a 85 1.2mm lens can), and at the same time, my binocular vision seems to distort the world less at close distances than a 15mm at its minimum focus distance can. Understanding how we see I believe is essential to understand to be a good cinematographer, just as much as understanding how the camera ‘sees’ and how these two are very different - and the creative endeavours this allows. (Think of how much work goes in to lighting a scene to create even exposure and separation for camera which renders its world in 2D, and all of that is mostly not needed when you see the same scene simply with your own eyes 🧡 🎬 (obviously there are the opposites too where the camera absolutely can see what we can’t), makes me marvel at the wondrousness of our ability to see!🧡).

[@sanyihegedu]

Panasonic Leica DG Nocticoron 42.5mm F/1.2 fits perfectly. A fabulous portrait lens for MFT

[@neobluepill6051]

I like the focal length of 40mm on my m43 Olympus camera, especially the Lumix 20mm F1.7 lens which has a 40mm with 4/3 aspect ratio.

[@rickbiessman6084]

Thanks for breaking down this issue in such an easily digestible way! I always get annoyed when people claim that this or that focal length is how the human eye sees - when we obviously have a really, really wide field of view, but can also focus our attention to a part of that field of view. One thing that I was missing from the discussion (maybe something for a follow up video?) is the fact that perception of focal length changes with the size of the image we're seeing, or the distance respectively. Anecdotal evidence: when I first put a 35mm lens on my A7C and looked at the image through the abisally small EVF, it felt really unnatural and weirdly wide angle to me. Not so with other cameras. And when I put a 5.5" monitor on my camera, all of a sudden 35mm feels entirely different. When I view 35mm footage on my computer screen, it feels different yet again. And if I had the ability to stream an image directly into my brain, it would feel different yet again.

[@theowlfromduolingo7982]

I love the way you calculated the different values. Good work

[@futtymad]

Really well presented info. Thanks for taking the time to pull that all together and share it so well.

[@GlowBright333]

Great video, held me captive. Following the math interspersed with stunning cinematic clip examples. Using a cupola photo that represents the diagram of the human eye was a treat.

[@wolfcrow]

Thank you!

[@DrRussell]

In trying to represent medical pathology as the eye sees it for the last 7 years, I have realised; somehow, perspective distortion changes at different working distances, requiring different focal lengths. Therefore, 35mm matches within 50cm, 50mm matches between 50cm and around 3-5m depending on the pathology, 85mm matches between 5m and around 100m and above those distances, a larger focal length is needed. Varying too far out of this, and the subject is either excessively distorted or flat. Am I hallucinating?

[@Narsuitus]

The focal length is the distance between the optical center of the lens and the image formed when the lens is focused on infinity. Normal Lens (also called a Standard Lens)-a lens with a focal length that is equal to the diagonal of the format. The diagonal of a 24x36mm film image is 43.267mm. The diagonal of an APS-C image is 28.3mm. The diagonal of a micro 4/3 image is 21.6mm.

[@bigrobotnewstoday1436]

When Kai W was at DigitalRev TV he said the human eye sees at 43mm and only Pentax makes that lens.

[@firstletterofthealphabet7308]

As this video suggests, there is nuance. Anyone who denies there is nuance in the field of science would be a fool.

[@smepable]

Thank you for this. I was thinking for a Long Time that the rule that 50mm represents human eye is wrong and that we can shift between several focal lengths. Thanks for giving me the scientific data for my thoughts ❤

[@robertluxamafreethinker]

For me, the focal length that seems more pleasing to my eyes when it comes to film are: 35mm f/1.4 (Documentary and Romance or Comedy), 50mm f/1.8 (Action and Suspens) and 70mm f/2.0 (Emotion, Intensity or Exploring the interior of someone or something). And with each one, if I'm on a budget and I could have only one of them, I would use it to shoot an entire film with without any problem. (But a 24/28mm seems to wide and a 100/135mm seems to cropped to my eyes)

[@bk6020]

Awesome. One of my fave channels hands down.

[@il_moe]

Leica actually made a 40mm summicron C for the CL cameras. It’s M mount and quite affordable. Not may people use it because no M camera has the 40mm viewfinder lines.

[@steve-4045]

One rule of thumb is that a “normal” lens would have a focal length equal to the diagonal of the sensor. In the case of full frame, that is about 43mm. If you use a camera with a different aspect ration, such as 4:3 medium format, it is not so obvious what the focal length equivalents should be. Using the relative diagonals is a compromise, and sometimes you may want equivalent width or equivalent height. My first 35mm camera had a fixed 45mm lens, so that looked normal to me out of habit and experience.

[@rouuuk]

music name : Will Rosati - Lonely Troutman II

[@worldtrippa79]

Leica actually made a 40mm lens for the Leica CL in the early 1970’s. Rollei and Ricoh, among others, made 40mm lenses for their film point & shoot cameras.

[@izoyt]

First of all, human vision is bi-focal (stereo-vision) with depth perception etc . Human field of view is defined not just by two eyeballs, but also human features as nose, eye sockets etc. So, our actual shape of fov is something like pilot helmet visor, for example, with very wide angle ( if not almost true 180, than at least 120 as mentioned, but it is hard to be exactly determined, since this varies from person to person. This could somehow relate to wide fish-eye lenses etc, but what we perceive as a sharp image with depth perception/focus etc, is finally related to something like 45 mm in leica format as noted, but than again, you can't really compare this directly. I think all this should be mentioned at the video.

[@xfontan66]

What I have found is that whenever I have a 40 or 50 mm equivalent lens in my camera and look at the viewfinder, what i see is equivalent to what I saw with my eyes. 40 a bit wide 50 a bit strict. I always thought the right answer to the human eye was something between these two focals. Thanks for the excellent video.

[@bucketak]

That's why I love Pentax FA 43 so much.

[@joshmartonosi5624]

My preferred measurement and comparison of camera focal length vs the human eye is the size and distance objects appear in the foreground vs the background. As you know, wider lenses cause objects in the background to appear smaller and farther away compared to the object in the foreground, and vice versa with telephoto lenses. Using this definition, what focal length is most similar to the human eye? I believe the answer is about 42-50mm.

[@user-eh8jv2em2o]

There's no focal length that is most similar to the eye. When we're scanning a wide scene, our eyes are effectively taking in a broader view, akin to a shorter focal length. This wider perspective allows us to perceive more of the surrounding environment, similar to how a wide-angle lens (much wider than 42mm) captures a broad field of view in photography. Conversely, when we're focusing intently on a specific object or detail, our eyes effectively "zoom in," narrowing our field of view to concentrate on that point of interest. This narrowed focus mimics the effect of a longer focal length (much longer than 50mm), isolating the subject and emphasizing its details, much like a telephoto lens in photography. The breadth of our visual experiences varies greatly depending on factors such as our surroundings, what we're focusing on, and our individual attentional focus. Therefore, it's not appropriate to generalize our visual perception to fit within a specific focal length range like 42-50mm.

[@hyogaraj5036]

Excellent video for everyone specially for photographers.

[@bojangbg]

it's always the diagonal of the sensor/film which defines the so called Standard.. and it's always 43,3 in FF or 54,8 on a 44x33 Medium format... 21,63 on m43 sensors... and it always equals the same 43~ mm but it has nothing to do with the Human eye... we have two eyes... and there is a 3rd Dimension

[@SolidBlueBlocks]

Problem is: sensor diameter isn't always the thing you can measure across all aspect ratios. For example, the sensor of my Blackmagic pocket cinema camera 6k is wider, making it a 23.sth mm diameter. BUT the crop factor is around 1.558, and you won't get the 43mm with those measurements.

[@bojangbg]

@@SolidBlueBlocks now i took a short look on it... the diameter is 26,5mm and if i multiply it with 1.6 (1.558) yes... again the Magic number 🤭

[@beltenebrosgr1904]

Amazing video, thank you for sharing.

[@AlexDreemurr]

A big thing to remember when talking about vision is how your brain perceives it. While the actual *Physical* focal length of the human eye is around 25mm, your brain take the stimulation from the cones and rods and maps it out and distorts it such that it looks to be closer to 50mm. Your vision is something your brain does a lot of heavy lifting for, like how it removes the hole in your vision where your optic nerve starts, or removing your nose when looking forward, or filling in the blanks of your periphery when you're not looking at something directly. A fun (and funny way) I found to really test out the weird things that happens to your vision when you push it to the extremes is this: Have someone that you're close to (spouse, partner, sibling, or close friend.) Close one of your eyes and, with your open eye, put your face right up against theirs with your eye centered on the very top part of where their nose starts. If you keep your center vision focused there but then try to focus on your peripheral vision, you'll notice that you can still actually see both their eyes and even past their head, but it almost looks like an extreme fish-eye effect. Your eye, even less than a half-inch away, can not only see someone's eyes and cheekbones but even past them as well. When you see do this you actually get to somewhat really perceive how wide your FOV truly is (more akin to the actual 25mm distance) but in normal day-to-day activities and with both eyes your brain reformats your vision seamlessly to look like that 49mm-73mm range. The question isn't "what is the focal length of the human eye?", its "What's the ***perceived*** focal length of human vision?"

[@krectus]

yep, this. This is the real info that should be in the video.

[@JamesWillmus]

This makes sense to me. Since the eyeball can't really change it's shape that much, the brain selectively takes in information from the area of the retina which is most appropriate for the situation. If you stood on a hill and looked out across the landscape without focusing on anything in particular, you are taking in a wide field of view which lacks detail. If you then catch the movement of a deer in that scene, your brain relies on the center portion of the retina to analyze the potential prey. So you "zoom" in on the deer, even though all you are doing is focusing the eye on the target and allowing the brain to take render a detailed image from all that information.

[@CameraMystique]

For *Close to Far* (how far things are from each other and from the viewer), the 42mm is indeed closer to how human eye perceives distances. But not in terms of "how much of the scene" we see (field of view). If you hold your hand next to your head, your peripheral vision still captures it (almost fisheye field of view but not sharp). I would say the human eye is "an almost fisheye lens corrected like a 42mm for distance perception and distortion".

[@zoltankaparthy9095]

Really good and really informative. Thank you. FWIW the Hasselblad XCD 55V translates to a 35mm format 43mm lens.

[@pablogacitua]

And Fujifilm GF 55mm f1.7 as well👌🏽

[@nf_felix]

Best video on this topic I've seen so far

[@bwc1976]

Thank you so much, all of this makes perfect sense!

[@CarlosVixil]

Appreciate this. I’m relatively new to photo and found 35mm to be a relief but not quite there, and on the high end I don’t have the budget to figure out why my 135mm isn’t narrow enough, but 200mm photos online don’t do it for me either. I’ll have a better chance at finding my ideal lenses now.

[@HGQjazz]

I've always wondered about this! I look in my 35mm and it feels wider than what I was looking at. My 50mm feels 'cropped' when I bring the camera to my eye. This explains a lot! It's a shame the 42mm (ish) aren't more common. I know they're (40mm) used in cinema, but definitely not common in consumer lenses. Thank you for discussing this!

[@bwc1976]

My 1970's era Olympus 35RC film rangefinder has a 42mm lens which I love, and Panasonic makes a great 20mm lens for Micro Four Thirds digital whose field of view is equivalent to 40mm on full frame.

[@Zale-vj439]

Question: Does shooting on a crop sensor camera (such as Canon, at x1.6), with a 28mm lens, get you close enough (44mm)? or am I wrong?

[@videofan006]

Very good film, very informative, light on boring stuff, to the point. Thanks!

[@migranthawker2952]

Since the length of the human eye along its optical axis, from the front of the cornea to the retina is approx 24 mm, then I would suggest the focal length is 24mm when relaxed (i.e. focused on infinity), changing by distortion of the crystalline lens to a shorter focal length when focused on a closer object!

[@ryanroux5429]

Thanks for sharing A subject I enjoy

[@shred3005]

I like to think 43mm is. That’s the diagonal of the 36 x 24mm frame. Pentax has long had its 43mm f1.9 many have considered the ‘true normal’

[@fishypaw]

I've often wondered. You give a good, concise explanation of the relevant elements. I've always felt, it was a bit less than 50mm. So, 42 is not far off my estimate. The framing is interesting too. Cheers.

[@PaulB-gl1ix]

Nice. I’m a Leica M user, and always appreciate great optical quality. And… my latest purchase, the Hasselblad 55V is 43mm in 35mm measurement… Perfect 😅

[@punpcklbw]

The binocular "frame" is where the fields of both eyes intersect, so it should be equivalent to a 12x24 frame (stretched vertically), rather than 24x12. Our eyes are spaced out horizontally, not vertically, so the binocular area should be almost as "tall" as the entire field of view, but relatively narrow. Also, "retina", not "rentina". Otherwise, interesting way to think of an eye as sort of an "all-in-one" lens because of retina resolution increasing towards the center.

[@MarkAfterDark]

Love your work man!

[@wolfcrow]

I appreciate that!

[@Yodakaycool]

Very cool. Thanks for the video

[@wolfcrow]

You’re welcome!

[@vlcthefish]

Do this experiment; Take a zoom lens on your camera and focus on an object in your room. Lets say a TV from 8 feet away. Put the camera away from your eyes and then put the camera back up to your eyes and continue to adjust the zoom until the magnification matches what you are seeing in the real world. In full frame terms it will probably be somewhere around 65mm-70mm(Lets say it's 67mm). The caveat is that the full frame obviously show a extreme cropped version of what you see in the real world since it's only full frame. If you have the 67mm on a medium format if shows more the the scene and then large format again even more at the same focal length. This is one of the reasons why I hate wider lens for most landscape shots. A 20mm lens on full frame has too much distortion and it doesn't match what I'm actually seeing and even 35mm is too tiny...the only thing the wider lens are doing is letting me see more of the scene at a cost. This is the major advantage of the bigger formats. Ansel Adams for example shot a lot of Hasselblad 6x6 with a 80mm lens but it allows you to see pretty wide at 6x6 compared to full frame. It's also one of the reasons I love Nolan IMAX movies. He's shooting a lot with 80mm lens and the look is distinct from everything else.

[@Bigtbone205]

I did an experiment with a 20 to 70mm zoom lens where i carefully observed a street scene without focusing on any particular part. So just look straight ahead and noticing what was clearly in focus without moving my eyes around. I thought i was going to end up with 50mm as that is what i had been told for years was the normal vision. But for me the closest was somewhere in the range of 30 to 35mm. I still find 35mm the most normal looking focal length...but i also wonder if thats just years of looking at newspaper photographs growing up

[@lorenschwiderski]

It is all about the results of how a lens / camera see the world. The rendering of 50mm lens on the street makes for an easy composition and emphasis on a more narrow focus point. I have a Nikon 40mm lens, and find it perfect for street photography as it gathers in some of the surrounding area, like a 35mm, but without any distortions of a 35 or 28mm lens. It is a bit more focused view on your subject. The 50mm at times can work out better, should you need to take in something of interest across the street, and in travel shots, is pretty good compromise between wide and zoom. The 50mm is darn near impossible mess up in shooting composition, or going whacky with distortions, such as far edge, up close, or angled shots. I still use many different focal widths, with my 30mm being great when really in close, my new 40mm in most all cases, and longer lenses for tighter shots. The 28mm is neat, yet it can distort when shooting quickly, or simply not have the reach if needing to go much beyond 30 feet or so. It's all good! - Loren

[@blitzkopf7267]

thanks bro 50 was always narrow for me 35 quite perfect but it’s time to 40-45 by the way what is the b&w movies clips you use here?

[@kevinkelly2513]

My first 35mm camera was an Olympus 35 SP with a 42mm lens. I came to realize after many other cameras, that I liked to 42mm perspective on full frame. Unfortunately, not too many prime lenses in the 40-45mm range for full frame digital cameras.

[@xmeda]

Pentax FA43/1.9

[@stephanweiskorn6760]

Excellent video 😊!

[@motbag]

Thank you for not going to the click bait rout and getting to your point in the thumbnail. That alone made me sub. Interesting, well made video.

[@jeffsaffron5647]

To have a same perspective as human eye lens needs to achieve 1x magnification. Magnification = focal length / exit pupil. Exit pupil is give or take equal to the sensor diagonal lens is made for... in case of full frame ( 36 x 24 mm ) diagonal is d = √( 24^2 + 36^2) = 43.2mm 1 = focal length / 43.2 -> focal length = 1 * 43.2 = 43.2mm Meaning in theory with full frame lens to achieve 1x magnification would need to have a focal length of 43.2mm. In reality exit pupils are larger, to limit vignetting... how much depends on a specific lens, more expensive the lens... less it vignettes because they made the exit pupil larger.

[@jeffsaffron5647]

Also... this only talks about perspective not the actual field of view. Humans have huge field of view because the image we see is formed in our brains and it has very little to do what the retina actually sees at given point in time. We have two eyes our brain uses to construct 3D vision. That's why we have relatively wide field of view compared what 50mm or even 35mm lens has.

[@alex.muntean]

Wow, what a video!

[@wolfcrow]

Glad you liked it!

[@scoppens1000]

QUESTION Perhaps a weird one: can you (in away) explain the f-value of a human eye when focusing on an object nearby and when focusing on an object further away. I like scenes where your attention instantly switches due to focus pulling or focus switching. Gr

[@winc06]

Normal has nothing to do with the eye. Very simply a normal lens has a focal length equal to the diagonal of the film frame. It is an optical term. lt is really easy to determine the focal length of the eye which is something else entirely. Put a zoom lens on your camera and adjust it until the perspective in the viewfinder matches what you see with your eye. It is about 90 mm with 35mm format. The width of the field in a round eyeball has nothing to do with it.

[@super-z8943]

1. We see with both eyes which gives us a much wider view compared to a single eye. 2. Even if our eyes can selectively 'focus' on a particular central subject, the perspective of view never changes.

[@c.augustin]

That was very interesting! Works in photography too. And it explains why some photographers prefer 35 mm as their "go-to" focal length, some 40 mm, or 45 mm, or 50 mm (or even 55 mm). I'm comfortable with 35 or 50 mm, more leaning to 50 mm (for me it's more about details).

[@matthewsinger]

When I look through an old film SLR where the viewfinder is designed to appear at 100% magnification, the image I get with a 50mm lens focused toward infinity matches/lines up with the image that I see with the other eye. 50mm, give or take, seems to produce the same compression and angular perspective as human vision.

[@donnietobasco4526]

In my opinion when it comes to representational photography field of view is only a small part of the puzzle. Relying on field of view even when comparing focal lengths between sensors is vastly insufficient. To me what matters the most is compression. This seems to be a slept on topic when people are comparing lenses between full-frame and APS-C cameras (which is sort of what we're doing here). I don't use an 80mm lens on my APS-C because I want to use a 120mm full-frame equivalent. I use an 80mm because I want the same compression and look that an 80mm lens offers, regardless of crop. If I was shooting full-frame I would use an 80mm lens all the same. I want that look. Because to me that look recreates the features that my mind recreates. If I imagine a person, let's say it was Brad Pitt (picked because most of us can imagine Brad Pitt without looking up a picture), the image my brain puts together *feels* like it's at 80mm. When I take a soup can and bring it within a foot of my face, it doesn't look all distorted like a wide-angle lens would make it at the same "crop". It looks as flat as it would across the room. I hope this makes sense to anyone reading. Compression is a large reason why I use longer focal lengths in my photography.

[@timpanic]

Great Work!

[@Prisci_fh]

And what About sensitivity of human eye compare to iso sensitivity? Is there any reseach?

[@sh1maru]

An additional nuance is that we have strong brain post-processing. For example, when we look at a small object in the distance, our brain essentially crops the frame and the image from a 200+mm lens can appear very natural. Also, our eyes can move quickly, and our brain can stitch shifted images into one. So landscapes shots with an ultra-wide lens can also appear natural

[@shivakumarannigowda9983]

Wooooow superb video. More n more thanks sir n all teams ❤️💐🙏🎂❤️🙏.

[@EridenEstrella]

Focal length of one human eye is 50mm with an aperture of F2. The combined focal lenght of human vision with our two eyes is 24MM also F2.

[@s.z.x.01]

Actually Leica does have a 40mm M mount lens in collaboration with Minolta for the model CL, it’s also my only owning Leica M lens at the moment

[@MarttiSuomivuori]

Yeah! I have 40mm lenses. A Zeiss my Sony and Voigtlander Nokton my Leica. They are very useful lenses, especially the Zeiss. The Nokton is unbelievably sharp. I have it on my M10-R as default.

[@cdavey7654]

I don't know, but 40mm is one of my favorite primes (as it seems to be one of the most versatile), with 35mm being a close 2nd. Not a huge fan of 50mm, I always find it a bit too tight for many shots I am wanting. I've heard more than a few times that the reason 50mm was used so often was because it was sort of 'normal'-ish but mainly because it was easier and cheaper to make that focal length for full frame 35mm. Which still must hold true to a certain extent as often the 'nifty 50' is one of the cheapest prime lenses for FF camera lens. There are a few 42mm fixed lens compact cameras around so there must be something to that.

[@Qstrix]

An immaculate video! +1 subscriber here

[@zainalshawi1980]

Great video ❤️👍🏻

[@PavlosPapageorgiou]

It's around 40mm for me. 35 is too wide, 50 is often tight. On Canon I can get that by putting a 25 or a 28 on a crop sensor and that feels natural for a walk around.

[@WizardOfCheese]

5:37 i share this 'view' that we have different focal lengths depending on what we're looking at. from 20 to 60. makes sense why 35 is so popular.

[@ergojosh]

Finally someone went and did their research on this! I think it's simultaneously coincidental and intentional. Cameras are made by humans for humans to use to make things for other humans to enjoy. It just goes to show you how brilliant and intuitive the early engineers and photographers were even before the advanced technology of today.

[@lucianoag999]

The natural focal length depends how the picture is going to be seen. How much of the field of view does the picture take when you look at it due to size and distance. Let’s say you look at a 15 cm x 10 cm picture at 40 cm away from you. That represents a field of view of roughly 20 degrees. Your camera and lens system should then have the same field of view. For FF you would need 96 mm. Like that taking a picture would be like putting a 15 cm x 10 cm frame at 40 cm from you and recording what you see inside. Shorter focal lengths would allow you to see more inside the frame that’s what you normally do and longer would allow you to see more. Both feel “unnatural “. The formula for this definition of natural focal length =picture distance / picture width x sensor width. If you know the focal length a sensor size use for a movie, you can use the formula to sit at the “natural” distance from the screen at the cinema.

[@NothingXemnas]

With this in mind, I am imagining what a video would look like by recording with 4 cameras with different lens and filter settings and editing the videos together in concentric circles; most focused at the center, and least focused and most distorted on the outside.

[@Tom-vn4uu]

Very interesting. Thank you.

[@wolfcrow]

Welcome!

[@viniciusmv7727]

I've seen sometime ago another explanation, don't know how scientific it is. That 42mm is the focal length where the relationship between the distance of an object and the size it has on the frame more closely resembles the relationship we see with our eyes. In that sense it's not about the FOV, it's about depth perception.

[@LuigiL75]

Hence…the Tamron 45mm F/1.8 being my all time favorite “Nifty Fifty” on two separate mounts! 🙌🏾

[@IAMDIMITRI]

Shower thought but: What if people have different focal lengths because image is reproduced in the brain. Even if the resolution is better at the center, you still can perceive motion by the large portion of the eye, giving you theoretical focal length that is much larger. Stationary human have probably some focal length that is represented by how much information you can resolve but the ability to move the eye and keep that surrounding information in mind you can have much larger focal length. You don't need to see the tree that is 90 degree to the right of you, you already saw it once and you know it's there. Same as with any picture, even if you can capture a picture you still need time to look around. Thus focal length of humans can vary depending on how much visual information they can keep track off and process. Equivalent to panoramic mode in phones, it's standard FOV until you move your phone and process your picture. If we follow this though then human have much larger fov than 50mm equivalent can provide depending on visual processing power. If we don't follow this though then you can't even resolve letters around this word properly giving you really really small fov.

[@nijiirofurea]

Pentax FA 43mm F1.9 LIMITED makes more sense than ever then =)

[@8KHDRVideoBySittipong]

Very informative video.