The 50mm is exactly what the human eye sees, without any distortion
September 19, 2013 7:52 PM   Subscribe

The Lens Is Standard, the Photos Anything But Jerome Delay has been on a quest for simplicity while covering some of the most important stories in Africa for The Associated Press. For the last year he has relied almost exclusively on one camera, and one lens, a 50-millimeter F1.4.
posted by ColdChef (41 comments total) 32 users marked this as a favorite

 
An old, only barely relevant, story from film school: Back in the late '70s, Robert Altman was working on the long-forgotten film Quintet, and wanted to do something special with it, and so commissioned a highly expensive bespoke set of lenses designed to blur out at the edges in exactly the way the human eye does for the effect of enhanced realism.

When looking at his first dailies he realized that the human eye does it's thing just fine when watching the film and that the only "effect" of his lenses was nausea.
posted by Navelgazer at 8:08 PM on September 19, 2013 [9 favorites]


Nice photos, great idea. I love normal primes.

That said, isn't 43mm the "perfect normal" on a 35mm frame? As a Pentax fan, I feel obligated to pick this particular nit.
posted by Sticherbeast at 8:09 PM on September 19, 2013 [5 favorites]


Interestingly though, his Twitter photo shows him using what looks to be a 70-200mm (white, so Canon L series).

I went around the world shooting on nothing but a 50mm 1.8... but I was on APS-C, so it was a bit closer than I'd like most of the time! I disagree that 50mm on a full-frame sensor is "exactly what the human eye sees," though.

More importantly, amazing shots.
posted by BlackLeotardFront at 8:27 PM on September 19, 2013


the only "effect" of his lenses was nausea.

It's not the lenses.
posted by charlie don't surf at 8:33 PM on September 19, 2013


Yeah, that's a great way to shoot.

I find the headline detracts from the work, though. They're great photos, to be sure, but they really are pretty much standard in most regards - just well executed. It is a little remarkable how consistent he is with composition (centered subject, right on the line of horizontal symmetry), though. I guess that's in service of achieving "simplicity" and "directness", as the article says he was aiming for.
posted by aubilenon at 8:34 PM on September 19, 2013


43mm? I remember Minolta selling a ... 58mm... I believe saying that was the same as whet the eye saw.

Basically, they are all wrong anyway. All the 50 or 58 do is this: When you hold a 35mm camera up to your eye and look through it the size of objects doesn't change. Wide lenses make objects smaller, tele lenses make them larger. That's it.

I'm not convinced that 50 (or 58 mm) is actually the field of vision we perceive anyway.
posted by cccorlew at 8:34 PM on September 19, 2013


If you're using a modern DSLR, you really want a 30-35mm lens to match the angle of view of a 50mm on full-frame (sensor or film).
posted by pjern at 8:35 PM on September 19, 2013 [3 favorites]


I'm confused. When he's saying the 50mm is "exactly what the human eye sees," is he saying that it's the same magnification or the same field of view? Neither seems accurate. I'm estimating on the zoom lens on my APS-C camera, but it seems like 55mm is just about equal magnification. I'm assuming he uses a full-frame camera, so it seems like a 35 mm would be "exactly what the eye sees" for him or is my math reversed?

Either way, his shots are great. And I love my 1.8 50mm lens. Great pictures, small size, and CHEAP.
posted by jonathanhughes at 8:37 PM on September 19, 2013


In my experience (as a full-frame DSLR user), 50mm is closest to the magnification factor of my eyes, but has a narrower field of view. My 35mm or even 20mm primes seem closer to my natural field of view, but peripheral vision makes it sort of hard to do a direct comparison.
posted by good in a vacuum at 8:57 PM on September 19, 2013


Your math is reversed.

Also, camera viewfinder magnification is defined as how magnified things look with a 50mm lens vs the naked eye. So in that sense 50mm is literally the standard. But the size of the viewfinder (and thus the magnification) is not standardized, so even though the pictures will come out the same, things will look smaller one one camera than another.

I think really the "standard" is not comparing the lens's field of view with that of your eyes exactly. Humans have nearly 180° field of view if you include peripheral vision and stuff only visible with one of the two eyes - which is equivalent to like an 8mm fisheye. I think basically what "standard" means is that the FOV of a 50mm lens on a 35mm sensor roughly covers the area of your vision that is comfortable to focus your eyes on without moving your head. This means if you look at a print of a such picture at a comfortable distance, the scale and geometry will feel natural.
posted by aubilenon at 9:10 PM on September 19, 2013 [5 favorites]


50mm lenses, or 30mm on an APS-size dSLR, are a great starting point for thinking about seeing.

If you want to get good at photography, you have to learn what the differences are between how a 50mm lens sees and how you actually see. Then you decide how to make use of those differences.

Photography is as much a creative act as painting is. The main difference is that basic photographic technique is much easier and faster to learn.
posted by b1tr0t at 9:19 PM on September 19, 2013 [5 favorites]


An individual human eye has a horizontal field of view of somewhere around 140 degrees; for a 35mm sensor (actually 36mm x 24mm), this would correspond to a 6.55mm focal length [solve tan(140deg / 2) = 36mm / 2f for f].

Note that we can do this math the other way around as well: if a photo is taken at f = 50mm on said 35mm camera, it will have a horizontal field of view of very nearly 40 degrees. If you print this photo out at 10'' wide, then to 'properly' view the photo so that it takes up 40 degrees of your field of view, you should hold the photo 13.9'' away from your face (more generally, you should view the photo at a distance d = 1.39*width, so get out your measuring tapes to figure out how wide the photos are on your respective monitors).
posted by Pyry at 9:31 PM on September 19, 2013 [3 favorites]


I find that on both my cameras (full-frame DSLR, and 35mm film) it's up at about 70mm that it looks close to what I see, though obviously that means even less periphery.
Maybe I have telescopic eyes :-p
posted by anonymisc at 9:48 PM on September 19, 2013




The 50mm f/1.4 is a great lens, however....

cccorlew, you are correct. Minolta made an amazing 58mm f/1.2 lens that is often considered one of the finest ever made. I own one, and it is fantastic on every level.

For modern mirrorless camera users, the Sigma 30mm f/2.8 EX is probably the most optically perfect lens currently produced. The fact it can be had for around $100 used is just astonishing. How good, this good. Note: This was taken on a NEX-7, which has the single most demanding sensor currently produced.

All that being said, the best overall 50mm lens I've ever used is the Leica 50mm f/2 Summicron-R. Runs about $400-500 used and is amazing in every respect. This is a 1:1 (or 100%) crop on a NEX-6.

Okay, done now. Had to.....
posted by lattiboy at 11:10 PM on September 19, 2013 [3 favorites]


An individual human eye has a horizontal field of view of somewhere around 140 degrees

But most of that is periphery which is not very good for seeing details. The fovea only covers about 2 degrees at any one time. Of course when you look at stuff your eyes dart around shifting that here and there to take in details from a wider area. The full range you can move your eyes covers about 90 degrees - that's the stuff you can actually see in detail. But the far extents of that range are tiring plus your periphery gets full of distracting (because the two eyes see different things) images of your nose, cheeks, or eyebrows.

if a photo is taken at f = 50mm on said 35mm camera, it will have a horizontal field of view of very nearly 40 degrees

It's actually 46°. I'm not sure what the correct math is, I'm just reading this off of the specs for a lens. Your 6.55mm figure is wrong too, since a 8mm fisheye lens can cover 180 degrees.
posted by aubilenon at 12:45 AM on September 20, 2013


An ideal, distortion-free 140 degree lens would have a focal length of 6.55mm. You couldn't have a distortion-free 180 degree lens, because that would require a focal length of zero. A fisheye lens can cover 180 degrees, but at the cost of introducing distortion (i.e., straight lines are no longer straight).

The math is pretty simple for an ideal perspective camera (fisheye projections define their focal length differently):
tan(fov / 2) = image_size / (2 * focal_length)
fov = 2*atan(image_size / (2*focal_length))
focal_length = image_size / (2*tan(fov / 2))

The horizontal field of view of a 50mm lens on a 35mm sensor is 40 degrees; the listed 46 degree number is almost certainly the diagonal field of view, which manufacturers like to list because the number is bigger.

fov_hor = 2*atan(36mm / 100mm) = 40 degrees
fov_diagonal = 2*atan(43.3mm / 100mm) = 46.8 degrees
(43.3mm is the diagonal length of a 36mm x 24mm sensor)
posted by Pyry at 2:46 AM on September 20, 2013 [1 favorite]


I've got a Nikon 50mm 1.8 & almost never use it because it's so hard to compose with. I wanted a fast lens, but that thing befuddles me. I sprang for a used Tamron 18-200 so I wouldn't die backing off a cliff trying to frame something. Also, this guy is really good.
posted by Devils Rancher at 2:47 AM on September 20, 2013


The Canon 50 f/1.8, known as the "nifty fifty," has been terrific for me as a hobby photographer--it's dirt cheap (under $100) and extremely fast and sharp. (Here's the Flickr group dedicated to it.) Much like this guy, I used it as my only lens for years, with great results. Of course, on a crop sensor SLR, it's more like a 70, so yes, you do back up into the occasional wall.

I finally upgraded to a Sigma 30mm f/1.4, which gives me about the same frame as a 50 on a full sensor, and I'm loving it. Primes force you to think about the picture in a way that zoom lenses don't, and if money's a concern, you're getting a better and faster lens for the same price. People always seem confused when I take out a nice DLSR that can do less, zoomwise, than their smartphones, but the photos speak for themselves. As Mr. Delay says, the limitation is a strength because it forces you to think harder about what you're doing.
posted by muckster at 2:59 AM on September 20, 2013 [4 favorites]


Per Wikipedia, in still photography, the "perfect" normal lens will have a focal length of the frame's diagonal measurement. As such, I'm basically right about 43mm being the "perfect" normal focal length for a 35mm frame camera. (It says 43.3mm, to be precise.)

That said, the same Wikipedia article also confusingly states that, for digital sensors, "the sensor 'type' is not the sensor diameter". I'm not sure what that's supposed to mean, with regard to the apparent difference in Wikipedia's charts between the sensor diagonal and focal length of a normal lens? Why would the focal length of a "perfect" normal lens change between a 35mm film frame and a 35mm digital sensor?

It's tricky trying to claim that this or that lens truly mimics human vision. For one thing, humans have peripheral vision, but cameras do not. Robert Altman's quixotic attempt to mimic human vision by blurring the edges of the frame shows just how ill-fitting it can be to pretend that cameras are like eyeballs.

Either way, just as in life, "normal" is a range, not an exact point. 50mm is just a convention, but it's a perfectly good convention. 40mm lenses and 58mm lenses are all just as normal, for all practical purposes.

The Sigma 30mm 1.4 is a great, inexpensive normal lens for APS-C cameras. The Panasonic 20mm 1.7 is a great normal lens for M4/3 cameras.

FWIW, my earlier reference to Pentax comes from the fact that Pentax is one of the few manufacturers to make a 43mm lens. This is somewhat ironic, given that Pentax no longer makes 35mm frame cameras.
posted by Sticherbeast at 5:23 AM on September 20, 2013 [2 favorites]


All of this math is completely beside the point. Every photograph is an interpretation of reality. No matter how apparently undistorted, the photo cannot be "exactly what the eye sees". A good photograph is all about choices the photographer makes for the viewer.
posted by gilrain at 5:30 AM on September 20, 2013 [4 favorites]


The Sigma 30mm 1.4 is a great, inexpensive normal lens for APS-C cameras. The Panasonic 20mm 1.7 is a great normal lens for M4/3 cameras.

I like my Sigma, but it is a bit soft and is kind of heavy. If I had to do it over again I'd get the Nikon f1.8; lighter and cheaper, for a half-stop disadvantage.

To reiterate, the 'perfect normal' is kind of an approximation- human vision is hella complicated. The perceptual effects present in the visual system will make a 'portrait' lens resemble what you see in the mirror better, I'm told. Working at a fixed focus is helpful in a composition mastery sense and in that it gets you faster, often sharper lenses, but 'natural' is not always the best descriptor. You generate images, not views, with a camera.
posted by monocyte at 6:04 AM on September 20, 2013 [1 favorite]


images that are both accessible and aesthetically pleasing.

...

“I try to apply the rules of contemporary art to news photography in order to make pictures that will be more likely to be looked at,” he said.


Oh man, that is the truth. He uses strong design elements to draw the eye and make interesting images. Even something simple like number 15 with a child waiting for food has a strong background of the line of people which draws the eye from the edges of the frame to main subject. My favorite is number 2 with the child walking among the posts and shadows. Great stuff!
posted by caddis at 6:18 AM on September 20, 2013


Math math math, and almost everybody is missing the point.

I'm not sure where I heard this but it works for me. If you put your arm straight in front of you, hold your thumb in the "thumbs up" position and stare directly at your thumb, you are legally blind in any spot outside of what your thumb covers up. That's the focal area of what the human eye can see clearly at any given time.

Any camera that wants to accurately recreate what the human eye sees would need to duplicate this. But clearly... that's not what either photography or art has ever sought to do.
posted by Blue_Villain at 6:38 AM on September 20, 2013


It's a bit of a reiteration of what others have said, but the main advantage of shooting with a normal prime isn't so much that it's 'exactly what the eye sees', but more that by limiting yourself to a single framing option, you have to think and work with the other options you have. This forces you to work hard on the framing, and brings other options to the forefront like depth of field and shutter speed (this is why you want a fast fast fast lens - you have a broad range of options even in low-light conditions).

By holding one parameter constant, it should force you to think about and vary the other ones, and also to really think about framing and composition.

This almost inevitably leads towards better photographs. I owe quite a lot of learning to my 40mm equiv. f/1.7 lens, and it is still my favorite.
posted by grajohnt at 6:51 AM on September 20, 2013 [1 favorite]


Arguing over which lens represents true human vision is just total wankery given the complexities of human vision versus the simplicity of a camera and lens. Human vision includes peripheral vision and a central field of vision plus a brain which can direct its attention to various aspects of what the eyes can detect plus can ignore some things which are even in the central field of vision. Wank on folks.
posted by caddis at 6:53 AM on September 20, 2013


The trend for mirrorless systems to include at least one "normal" pancake gives me a happy. I had a Zeiss 45mm for my old Contax, and I used that lens everywhere. I'm saving up for Fuji's 27mm example (the "standard zoom" is as dreadful and uninspiring to use as I feared it would be, but it takes a fine image. Fuji is an unsung "third player" in the small format fine optics game after Zeiss and Leica. Their medium format experience really paid off for their X-series lenses.)
posted by Slap*Happy at 6:56 AM on September 20, 2013


Spending some time using only one fixed-length lens really helped my photography. I don't really think it matters which length you choose. Like grajohnt said, it brings framing and composition to the forefront, and it also gets you in the habit of moving to a different position to get a better picture.

Personally, I feel most comfortable with a fairly wide-ange lens, ~30mm equavalent on a 35mm camera.
posted by Quonab at 7:10 AM on September 20, 2013


I kept a 28 mm prime on my old K-1000 most of the time, and learned to appreciate the way it distorted the dimensions of things at the edges, and eventually learned to use it to my advantage, especially with landscapes. It made for great sunsets by doing weird things to the clouds. This and this are a couple of my favorite things that I shot with that lens, and this sunset.
posted by Devils Rancher at 7:14 AM on September 20, 2013 [1 favorite]


The lens most like the human eye is the fisheye lens. A fisheye lens doesn't distort the image, putting everything in rectangles distorts the image!

Any camera that wants to accurately recreate what the human eye sees would need to duplicate [the narrow field of foveal vision]

"Accurate" photography doesn't need to model the workings of the eye*. It just needs to model the display technology (which is generally flat & rectangular). Most of the weird distortion etc that the eye does to the real world, it also does to the photograph. When you look at a drawing of parallel lines you see them just the same way as you would "real" parallel lines. If you stare at a single point of a photo, you experience roughly the same narrow FOV as if you stared at the same point in the actual scene. Color-blind people don't find color photos especially unrealistic.

* Understanding the eye does let us take some shortcuts though. Like RGB color.
posted by aubilenon at 7:17 AM on September 20, 2013 [2 favorites]


I'm a hobbyist shutterbug, but I've had my happiest shooting experiences with "eye-like" primes -- first, the aforementioned nifty fifty on my old Canon Rebel, and the the Panasonic/Leica 25mm/1.4 on my Olympus E-M5.

The Leica/Olympus combination is substantially more fun, and I get much better pictures, but then again it's a newer platform. If you're shopping for a big-boy camera, and haven't considered the micro 4/3 world, you really should -- it's amazing what's being done there, and at this point you don't give up much despite the smaller sensors. (And what you DO give up comes back to you in portability.)

The biggest drawback up to now has been the lack of decent zooms, which hasn't bothered me because I prefer primes. However, Olympus has announced two "pro" class zoom lenses for m4/3: a 12-40mm constant f/2.8 which is already available ($999), and a longer version from, I think, 80 to 150 coming next year (also constant 2.8).
posted by uberchet at 7:55 AM on September 20, 2013


What these photos say to me is that your pictures will be so much more impressive if you just get on a plane and fly to a war zone in the middle of Africa.

As for lenses, I found a good deal on a small micro 4/3rds camera as I just never carried around the wonderful but clunky Nikon but now when I really want to have it pocketable, the pancake lenses seem just great but woo, not inexpensive.
posted by sammyo at 8:54 AM on September 20, 2013 [1 favorite]


No camera sees what we see. Each eye sees a circular view, not rectangular. It's wide angle but it is only hi-resolution in the center. We don't notice because we are constantly moving the good part of our vision around to scan the things we are interested in. In some ways a wide angle lens like a 20mm is like how we see, but an 100mm is also how we see as it's like the part of our vision that we care about.
posted by w0mbat at 9:57 AM on September 20, 2013 [1 favorite]


No camera sees what we see.

We don't see what we see. There's a lot of post-processing going on in the ol' noodle to get around the limitations of generally crummy eyes. One of these is a left-right/up-down bias, so we visualize things in memory and imagination in ways that generally align up with the rectangular format. Camera lenses certainly do capture a circle rather than a rectangle - but the imaging sensor/film is rectangular 1) for ease of design and manufacturing and 2) Anyone who's ever seen a painting or wall mural knows that humans do actually "see" in rectangles.

Telephoto and wide angle focal lengths (not the lens design, the actual wide or narrow focal length as determined by the lens and sensor size) distort the subject in ways our brains don't - this is useful when trying to cram a lot of stuff into the frame, or get a really close-up shot of something far away. A "normal" lens does not noticeably distort the subject, and presents a field of view that's most compatible with the way people visualize things.

So, no, a 50mm does not exactly match the human eye or some such mumbo - it just presents a photographic depiction that is familiar and easy for humans to visualize. This is why it's such a favorite tool of photographers.

Now, another case can be made for the full frame 35mm as the "normal" focal length for similar reasons that use a different criteria, but that will drop us right into the middle of a long-running (decades!) camera-nerd holy war, so I will refrain.
posted by Slap*Happy at 10:47 AM on September 20, 2013 [2 favorites]


I meant to add that I think there's an awful lot of overthinking the general rule that 50mm is roughly human field of view/apparent distance on 35mm and full-frame DSLR cameras.

Obviously, there's a lot more going on, but in the general case, it's true enough to use as a rule of thumb. Everything bigger is telephoto. Everything smaller is wide angle.
posted by uberchet at 4:57 PM on September 20, 2013


Slap*Happy: " 2) Anyone who's ever seen a painting or wall mural knows that humans do actually "see" in rectangles."

I've seen paintings galore, and I have no idea why you think that the tradition of building rectangular buildings and square canvas stretchers has anything at all to do with human vision.

We clearly, undeniably see in a projected cone. Go ask your eye doctor, or look up the human retina in Wikipedia: there's no rectangular edges to it.

In any 2-d slice, our vision is circular, like a lens - not rectangular, like the detectors in 99.99% of the cameras in the world.
posted by IAmBroom at 9:21 AM on September 21, 2013


Blue_Villain: "I'm not sure where I heard this but it works for me. If you put your arm straight in front of you, hold your thumb in the "thumbs up" position and stare directly at your thumb, you are legally blind in any spot outside of what your thumb covers up. That's the focal area of what the human eye can see clearly at any given time."

Right idea; wrong starting assumption.

The foveal angle is about 15 degrees, so the FOV of your fovea at arm's length is approximately 24*tan(15 deg) = 6 inches wide. Or roughly about the size of your hand (which is somewhat narrower and somewhat taller than 6").
posted by IAmBroom at 9:27 AM on September 21, 2013


We clearly, undeniably see in a projected cone. Go ask your eye doctor, or look up the human retina in Wikipedia: there's no rectangular edges to it.

I think you're missing the point... which is that what the eye captures and what we actually do with the information it passes along are two differnt things. No-one visualizes in a cone. Pay attention to what your eyes do the next time you look at something cool, like a classic car. They go side to side, up and down, and then begin roving to notice detail in the frame you've just made to encompass the cool car.
posted by Slap*Happy at 10:02 AM on September 21, 2013


Slap*Happy: "They go side to side, up and down, and then begin roving to notice detail in the frame you've just made to encompass the cool car."

I'd doubt that assumption very much, since I've seen graphs tracking eye-movement. The eyes have absolutely no reason to move in rectilinear ways, and don't.

Plus, to a certain extent you may be describing a bias brought on by the nature of images in our lives. Ask a child to draw a scene on the sidewalk, or on a gigantic piece of paper, and you won't find them bounding the image inside of a rectangle.
posted by IAmBroom at 1:34 PM on September 23, 2013


I prefer a 35mm lens on my D90.
posted by mike3k at 2:04 PM on September 24, 2013


I prefer a 35mm lens on my D90.

That's a normal lens! The FOV is equivalent to that of a 52.5mm lens on a full frame camera.
posted by Sticherbeast at 2:22 PM on September 24, 2013


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