Recently I've concluded that most professional photographers actually believe that telephoto lenses compress the subject and background in an image and that simply is not true.
I got a call from a local photographer last week. He knew that I had recently filmed a tutorial on architectural photography with Mike Kelley and he had a question about lens distortion. While he was photographing a home interior, another well known and successful architectural photographer in the area approached him and offered to give him his "secret technique" to produce distortion free images. Instead of shooting one vertical 17mm image (which has significant distortion in the edges because it's so wide), he suggested that my friend shoot three horizontal shots with a 50mm lens while tilting the camera from top to bottom and stitching the files into one photograph. My friend was shocked by the simplicity and potential of this suggestion and called me to confirm it. "Is it really possible to get distortion free images this way?" He asked. No it's not. In fact the images will have an identical field of view.
This was impossible for my buddy to believe so he had to put it to the test, and after comparing the two shots he found that I was right. The wide angle shot looked identical to a stitched shot created with multiple images from a longer lens taken from the same location.
After the test he called me to tell that the distortion was indeed the same but he was still convinced a longer lens would produce more "lens compression" meaning that the foreground and background objects would appear closer. I then blew his mind for the second time; "You realize that if you take a portrait of someone with a telephoto lens and then take the exact same shot with a wide lens from the same spot but crop into that image, the 'compression' will look identical," I said. My buddy simply could not believe this to be true. He had always been taught that the lens was doing the "compressing." After quizzing a few other photographers I realized that the majority of professional photographers I know didn't understand this either.
Lens compression has nothing to do with the lens and has everything to do with your distance from the subject.
I explained to my buddy that lens compression doesn't happen in the lens, it happens when you physically move the camera back. No matter how I explained it he wouldn't believe me until he did the test himself.
Why do we use the term "lens compression?"
Most photographers believe that the lens is "compressing" the scene because they will take a test shot with a wide lens, and then back up to capture a similar composition with a telephoto lens. It's easy to see that the telephoto shot is far more "compressed" and it's also easy to completely overlook the fact that the camera has been moved and the field of view has changed.
Why does compression happen?
Imagine you are photographing a person and behind that person is a mountain. Let's say your subject is one foot away from the camera and the mountain is one mile behind your subject. From this distance the person's face would look huge compared to the mountain because the person is exponentially closer to the camera than the mountain.
To make the person half the size that they currently are in the frame, you would have to move back only one foot, doubling the distance of the camera from the subject. But when we half the size of the person by moving back one foot, the size of the mountain remains almost identical because to make the mountain half the size you would need to move the camera back one mile. This ratio between the distance of the subject and background to the camera is what causes compression.
As you continue to move backward your subject will get smaller and smaller and the mountain will remain about the same size. To keep the subject the same size in the frame, you will need to zoom in using a lens or "crop in" in post and as you do, you are enlarging both the person, who has been shrinking as you back up, and the mountain, that has remained basically the same size.
When we look at the final images it may appear that the person is the same size in each picture while the mountain is growing but in reality the opposite is happening. The mountain is staying the same while the person is shrinking and we are zooming in to compensate.
Here's Proof
In this gif below you can see two images that Elia Locardi took during the filming of his landscape photography tutorial. In both shots, the camera was in the exact same place on a tripod. The image on the left was taken with a 16mm lens and the image on the right was taken at 145mm. Notice that when we "crop in" or "digitally zoom" the wide shot, we can get an almost identical looking image to the shot taken at 145mm with the exact same "compression."
Conclusion
Compression is a real thing but it really doesn't have anything to do with a lens. It has everything to do with your distance from the subject/background. You could get a shot with identical compression if you stand in the same location and take a photograph with a telephoto lens, a wide angle lens but crop in, or a camera with a "digital zoom." The magic isn't in the lens, it's in simply backing up.
And all of this leads back to the very beginning of the article. Is it possible to create a distortion free image by stitching multiple telephoto images rather than using a wide angle lens? No, because the distortion/compression is caused by the location of the camera in relation to the subject and not by the lens. If you stitch multiple images you'll end up with a higher resolution shot that has identical compression.
This does not mean that telephoto lenses are obsolete. Long lenses allow us to back up and zoom in without losing resolution; everyone knows that. But this post simply explains the phenomenon of compression in general which many photographers do not fully understand.
Take the poll
In talking with my photography buddies about this I've discovered that most photographers do not seem to know this. I'm curious how many of you reading this also didn't know that lens compression doesn't really exist. Take the poll below and let's find out.
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Yes, I read the whole article. So what would you call the exaggerated facial features created by a wide angle lens vs. the "compressed" look of the facial features taken with a 200mm lens? Most of us refer to it as compression but you seem to not want to use that term. ...Oh I see, you are not saying compression doesn't exist are you. You're saying the lens isn't responsible for it. Seems like a silly argument. I can tell when a person is photographed by a 24mm lens vs. when they are photographed with a 85mm or 200mm lens. The facial features look compressed with the longer lens hence the term compression I figured. I'll still refer to it as compression of the image regardless of the technical bs. Personally, I've never used the term "lens compression". Image compression sure, but not lens compression.
Yes, lens compression doesn't technically exist but perspective compression does. You may say this "is a silly argument" but a massive portion of the photography community doesn't understand this. A commenter above just said a guy went out to an air show with a 600mm lens rather than a 200mm lens because he liked being able to "compress the blue angels together." Obviously he doesn't understand compression and this article is for people like him.
No, it is the movement of the camera not the lens choice, If he had shot the 16mm lens from the same position as the 200mm lens and then cropped the image to the dimensions of the 200mm, the field of view and the tree in the background would look identical.
But if you really want to get pedantic you could say that your distance from the subject is "caused" by the length of your lens so there is a causal relationship between lens and compression, but not a physical.
Incorrect, the angle of view and level of magnification in the lens means that the background will be different between the wide and tele lenses shot from the same space if the wide is cropped to give an equivalent framing of the subject. Lets say you shoot a headshot at 200mm, if you then take the 200mm off the camera and replace it with a 24mm and take the same shot from the same location, the wider angle of view will "expand" the background behind the subject so that even if you crop in to the same framing, the background shown behind the subject will be different.
Yes I did. At stupid distances compression becomes moot. At working distances for the average portrait shooter it's a very different story however. I have actually tested this with a 24mm and 200mm lens. At a typical headshot distance for a 200mm lens. Taking a shot at 24mm and then again at 200mm from the same place (camera on a tripod) and shooting a subject in front of a poster. Crop the 24mm to the same framing as the 200mm and the background will be different.
When you say "the background will be different" that may be true in regards to bokeh, dof, and resolution, however they will have identical perspective and identical "compression".
Nope. That's exactly what I thought as well. Great post on Fstoppers.
Timothy, that is a double incorrect :)
If you stand in the same spot, you could change focal length all day long and it will be no different from cropping. The only two variables that can affect the size of the background relative to the focused subject are aperture and camera to subject distance.
Try it yourself with a zoom lens and you will see the results very quickly...
I can say the lens has no effect on the equation, and i would be right if the equation had no location for "resolution" in its problem.
So here it is: "the lens has zero effect on compression if resolution is of no concern".
Now since as long as i can recall, resolution is very much at the forefront of many photographers list of things they want. So in that regard, compression, very much has everything to do with lens choice, if resolution is a primary concern.
Forget resolution. No novice to photography is being taught, “here is how you get resolution to make a great image.” What they are taught is perspective, (choice of position), and framing, (choice of lens:film width).
When a landscape photographer chooses to go with a wide lens, does his “resolution” suffer? No. The resolution of the distant tree may suffer but that is immaterial to him. What matters is whether the tree is in a good position relative to everything else, (perspective), decided by his position, and where in the frame (or how much of it is in the frame) relative to everything else, (focal length).
The same is true for a sports photographer, (except, depending on the sport, he may not get much choice in composition). He chooses his position first, (composition), then he chooses his focal length (zooms appropriately), before shooting (framing).
Ultimately, your position/composition dictates the compression, your focal length dictates your framing, your camera manufacturer determines your resolution. If you want greater resolution, buy a different camera.
Great article Lee, I'd never thought that far into it before and always assumed it to be an effect of the lens. Consider my mind changed.
Lee,
The words you're looking for are "Perspective Distortion". ;)
Ding! We have a winner, thank you [ Timothy Tichy ] for writing
"... The words you're looking for are "Perspective Distortion" ..."
Yes.
Distortion is the difference between input and output.
What we have here is the difference between
-- the input angle of capture
-- and output angle of presentation.
Keep them the same, and there is no perceived distortion.
Change them, and there is perceived distortion.
It really is as simple as that.
Thanks for exploring this and sharing.
- - - - -
PS, I've been writing this for years, as Ansel Adams also preached it once he figured it out, here's one of mine from 4 years ago, I have more that go -w-a-y- back:
https://learn.zoner.com/prime-lenses-one-focal-length-many-benefits/#com...
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The poll is even 50:50
The biggest revelation in 2016. The longest running myth is finally demystified.
Oh boy... just scrolled through comments. Lazy is a good way to summarize everyone trying to debate this concept. There's A LOT of very clear studies from the academia that debunk this very phenomenon and go into much deeper science to essentially prove the point of the article.
All variables, including camera distance/angle from the subject/background, being equal give you the same "compression" no matter the focal length.
Mind blown😵
The poll shows 50% of photographers didn't know this
Most people don't know the chemical composition of air but successfully breathe it anyway.
I know it quite well, but sometimes, I forget to breathe. ;(
Most of the times I forget to breathe are just before some of my best shots. :-)
I miss those days that I really don't know anything. Doing my photography and trial and error basis. Then when you get a good shot, that's it - you simply adore it! No technical stuff to think about, bla bla bla...
And why does this matter, practically?
Plus: while it might be true that it is caused by distance from the subject, to say it has nothing to do with the lens still is not true. Try shooting an env. portrait from 15 feet away with a 16mm to get the same effect like e.g. with 200mm.
(Even if you crop it you still wouldnt get anything printable anymorem not to mention the BOKEH)
5m away with a 200mm lens to take an environmental portrait? Why would I take an environmental portrait from 5m away with a 200mm lens? Oh wait… you mean with a 10×8 inch camera? Yep. Same perspective, same “compression”, same image, and if I use the same aperture diameter, same bokeh, and quite printable.
Perspective is decided by your position, (in this case, 15 feet from subject), and framing is decided by focal length/film size, (whether 16mm or 200mm, whether on a MFT, or a 10×8 inch view camera).
I've not heard of lens compression until today. When I was at film school, we called it perspective foreshortening. Its understanding was key to setting up the shot.
Sounds like a more accurate name to me
Yeah, but, "compression" fits on my name tag better.
Good summary Lee! Perspective is something many photographers have a hard time understanding, which is quite normal, as it can get quickly confusing.
A couple of things to add to the discussion:
1) While change in focal length of a lens gives the same effect as zooming in post, since camera to subject distance remains the same, some wide angle lenses do exhibit more or less distortion due to their optical design. While it usually does not matter for the center of the frame, subjects placed at the extreme areas of the frame can appear distorted differently at the same focal length on different lenses due to differences in optical design.
2) Change of focal length without a change of aperture in a zoom lens does affect the size of the entrance pupil. This means that a lens shot at its longest focal length will yield a more blurred background relative to the subject compared to a shot taken at the shorter focal length. For example, shooting with a 70-200mm f/2.8 lens at 200mm @ f/2.8 will yield a more blurred background compared to a shot at 70mm @ f/2.8. However, the "gotcha" here is again camera to subject distance - for this change to be seen, one would have to walk away from the subject in order to keep the same framing, which triggers a change in perspective! Again, if the camera to subject distance does not change, zooming in or out will be exactly the same as cropping in post. Hence, your summary of camera to subject distance being the most important variable is absolutely true.
The only change I would recommend is to the title of this article - I think it would be better to call it "Telephoto Lens Compression Doesn't Exist", implying that using a telephoto lens does not somehow make the subject more isolated from the background. In order for any change to be seen relative to the subject vs the background, either aperture or camera to subject distance must be changed. Whenever one zooms in or out, they will most likely change the camera to subject distance anyway, in order to keep similar framing.
Hope this makes sense to other readers.
Keep up the good work Lee!
As a teacher of photography for 28+ years-this "take" on the whole discussion makes the most sense to the science. It is about camera-to-subject and subject-to-background distance and perspective....in film/cinema they will do a "zolly" that demonstrates this most effectively...zoom+dolly move: camera moving back as the lens is zoomed in or camera moved forward while the lens is zoomed out...the change in facial and background perspective is very pronounced and is oft used to give a "weird" or heightened moment in the film...or in the case of "The Quick and the Dead" to lampoon certain spaghetti westerns. :) Still photographers use the technique all the time for composition decisions...which also involve FOV and DOF.
I believed in Parallax! All hail Parallax!
I think we're arguing semantics here. In the end, the result is that using a telephoto lens ALLOWS ME to compress the background / features better than a wide angle lens if I frame my subject identically in both shots.
I guess the distinction is important in an academic type of way but in practical use it is USUALLY a bit irrelevant unless I'm missing something.
It's kind of like people who make a big fuss over film grain vs digital noise. Yes, there is a difference but is it worth making a fuss about?
Honestly, this is a silly article. Who cares about so much science. We have a variety of lenses for a reason. Everyone wants to be right in their argument..All I know is different focal lengths in your camera bag help me get the job done..Nuff said..
The people who care about science are the people who make it possible for you to be a photographer in the first place.
Ironically enough this same visual perspective discussion also dings off the previous FStoppers bad choice of headerline click bait regarding the iPhone7 vs DSLR discussion...cell phone won't be able to optically duplicate the effect of distance/lens focal length perspective.
Wow Lee, I came with a bias view but you've definitely converted it. Ha, it makes sense I must have known this when cropping my phones camera.
The short answer is you're wrong....more importantly you're confusing people. I know this because I got to this article after seeing TWO people completely misunderstand it and boldly claim "lenses don't create compression" on other forums, linking to here.
Which is false. It IS the lens.
To get the exact same composition using the entire sensor, the longer lens ENABLES you to be farther away which creates the compression.
If you start changing variables to fit what you WANT to be true, sure, you can do things like crop on the sensor to prove a fake point. But that's ENGINEERING a false proof.
No, the lens doesn't magically "compress" anything...that's never been the point. The point has always been that using a longer lens to capture the SAME COMPOSITION results in an image WITH compression.
Yes, the narrower your field of view (most effectively accomplished by using a longer focal length) without changing the size of your sensor, the more "compression" you get in a photograph.
And that LAST sentence is what matters most. Anything else is you trying to be the smart guy in the room and instead messing up a lot of learning photographers.
"No, the lens doesn't magically "compress" anything...that's never been the point. The point has always been that using a longer lens to capture the SAME COMPOSITION results in an image WITH compression."
That's the entire point of the article and perhaps you knew this already but 50% of the people reading this didn't know that and that's why this post is so popular.
Actually, compression, perspective, and position are all different sides of the same coin. When you spoke of, «…the exact same composition using the entire sensor,» what you meant was precisely the same “framing” using the entire sensor.
Position decides composition/perspective/compression. Lens/film size decides framing. Composition and framing are two different things.
I always tell my students: Where you stand is the most important choice you make in a photograph. Every other decision is subordinate to that first choice.
What changes is the compressión of the background and it changes the appearance of the DOF (keeping the distance the relative size of the subject in the frame equal in all shots made) here's a nice article that explains it rather well http://digital-photography-school.com/how-to-use-focal-length-and-backgr... it has better examples.
In Hollywood they use this trick, as an example there's a bomb about to explode and the heroes have to jump to avoid it, in reality the explosion is farther away to avoid hazard to the actors they use telephoto lenses for this trick.
From here there are other factors to consider like lens distortion and how it affects your subject, but that's another issue.
Are compression and distortion the same thing? When I hear/read "distortion" I think of the pinching or bulging that happens (fisheye, for example is very distorted). Am I off base here? I wouldn't call image compression "distortion" at all
Ps. The article is very good. I had read and believed that lenses caused compression
You are correct. Compression and “Lens distortion” are two totally different things, but many are too lazy to learn and understand, thinking that it is immaterial to them taking better pictures. That may be true enough, (I doubt it), but the real problem comes when they start to teach that nonsense to others.
As the poll shows, nearly half those polled did not know, probably because they were taught incorrectly. One sets their perspective (a.k.a., composition), by finding one's position, then sets their framing by choosing the lens.
Lens distortion is, in fact, a function of the lens formula, and may result in barrel (bulging) or pincushion (pinching) distortion, or whatever. People also talk about the bad distortion of fish-eye lenses, but do not talk about the bad distortion of rectilinear lenses. Rectilinear lenses keep straight lines straight, but distorts circles. Fish-eye lenses keep circles round, but distorts straight lines. One cannot have it both ways.
Man I can't stand clickbait article titles like this... now I'm going to have to deal with people on my own website/YouTube channel claiming that "Lens Compression Doesn't Exist", when it quite clearly does. The fact that the term is a shorthand for a phenomenon involving the lens and the photographer's position together doesn't mean that it doesn't exist.
Incidentally, I think it's pretty uncharitable to assume that most photographers (professional or otherwise) don't know that lens compression has to do with a change in the photographer's position rather than something inherent in the lens. Some would undoubtedly have trouble articulating the fact, but the same is true of just about anything. Many have probably never stopped to think about it... they just have a working knowledge.
Finally, some sense. Good article. Now write another article on how depth of field is/isn't a factor between telephoto/wide angle focal lengths (at same f stop) when subject fills same percentage of frame.
I'm personally still trying to figure this out for myself so that I can explain it simply. I know the answer but I'm not sure why longer lenses produce shallower dof from a technical standpoint.
Actually....they don't.
tele lenses do produce shallower dof than a wider lens. That's why the brenizer method works.
Tele lenses (=longer focal lengths) do produce shallower depth of field because they have larger aperture openings. When taking a picture with a 28mm f/2.8 lens at f/2.8, your lens has an aperture diameter of 10mm. At a fixed subject distance, this determines your depth of field. Now take a 100mm f/2.0 lens. At f/2.0 it has an aperture diameter of 50mm - much larger than the 28mm lens. The shallow depth of field is caused by parallax between different points of the lenses entrance pupil. Thus, the 50mm aperture opening has stronger parallax than a 10mm aperture opening, giving you shallower depth of field. If you had an 28mm f/0.56 lens (=50mm aperture diameter), it would show the exact same depth of field as the (brenizer) picture you are taking with a 100 f/2.0. Of course that lens does not exist but it is also wrong to say that shallow depth of field is caused only by the focal length.
Your argument is sort of invalid. First of all, if you crop say a 35mm to look like a 105mm, you lose a ton of resolution and your depth of field is totally different. As far as stitching is concerned, you take for granted that you shoot all of the telephoto shots from the same spot, which means that no frame is parallel to each other and more crucially to the central one. IF however, you shoot every telephoto frame from a different spot, keeping them all parallel to each other (so moving side to side), you can very well end up with a non distorted, high resolution image.