Lens distortion

<p>I know that we are all sensitive to this but I am seeing a lot of distortion on the media lately. <br>

You can sometimes see it on the front page of a newspaper where the people on the edges are flattened out. As well you can see that on renovation and real estate reality shows on the tube where the proportions of people's faces change as the camera pans. Then there are camera phones on Facebook. <br>

I think that this is becoming more accepted as time goes on. <br>

Still this does bother me and when I point it out people say, "it bothers you because you are a photographer."<br>

Comments?</p>

<p>PS: posting not Nikon specific but I am.</p>

I share your viewpoint. It seems that modern zoom lens designs trade geometric distortion for sharpness. Maybe that's a

good trade-off, I'm not sure.

 

When I look for new lenses, I look for lower distortion, if available.

 

In fact, my biggest criticism of the, otherwise excellent, 70-200/4 is the distortion. Some zooms, like the $1300 Nikon 24-

120/4 has such high distortion, that I do not consider it viable option.

<p>I think the broader acceptance of distortion by the general public is representative of lower standards of acceptance of a lot of things in general. Not necessarily bad, but not to my taste. We used to have a PN member who was a retired photo journalist, by the name of Al Kaplan, now deceased, who delighted many PN folks with his Voigtlander VC 15mm selfie street shots. I finally bought one but quickly grew tired of the distortion issues with a lens that wide, and sold it last year. As a truly amateur photographer, I'm not really bothered by seeing many distortion issues in others' works...I just pass over the ones which are unappealing and chalk it up to personal taste.</p>

<p>It bothers me a lot, even as a junk camera photographer, but not as much as the evening news being about what people have been saying on Twitter, or cute videos they found on You Tube.<br /> By the way, it's not the lenses' fault. It's the photographers who put people's heads at the edges of the frame with their point and shoot at its widest angle.</p>

<p>I think it's fine. The idea that photography is some sort of "truth" is patently absurd. Plenty of photographs have incorporated one form of another of "distortion" since the beginning of photography. FWIW, I do it on purpose frequently, it adds another dimension to the photo. I'm not really into the idea that photography should be more "accurate than a security cam.</p>

<p>Pierre is correct! Not the fault of the lens.</p>

<p>The reason we are seeing more distorted images these days is that our lenses are getting much wider, due to advances in technology. My widest rectilinear lens is a 12mm in the full frame format. However, decades ago, the widest lens available to me was a 24mm. Even 16 or 17mm in full frame is common nowadays. Obviously the wider the lens, the greater the "distortions."</p>

<p>That said, what most people don't realize is that rectilinear distortion (resulting in the stretching of 3 dimensional objects in the margins of the picture) is simply the normal consequence of mapping a three-dimensional scene to a 2-dimensional focal plane, and it's not really distortion at all. If you were to photograph a scene in full frame with a 12-24mm sigma, print the photo, and then view it at a comfortable distance, it would appear quite distorted. However, if you were to close one eye and put the other eye close to the print, viewing it with the same 122 deg (?) diagonal angle of view as the lens had of the scene when it was shot, it would look absolutely normal, with no distortion.</p>

<p>Oh, and does the distortion bother me? Yes -- I suppose because I'm a photographer. I notice it seldom bothers other people, although sometimes people will look in puzzlement at a wide angle group photo and wonder why the people on the ends look so fat.</p>

<p>Distortion bothers me. Lightroom fixes it. And then I have a snack.</p>

<p>All lenses distort. Rectilinear lenses distort areas at the edges while keeping straight lines straight. Fisheye lenses bend straight lines, but keep areas more or less in proportion. It all depends on what sort of distortion you want. It's not possible to map a 3 dimensional space onto a 2 dimensional surface without distortion. That's why all maps of the earth distort. You can pick a projection that keeps one geometric property "correct" but at the expense of others. The Mercator projection (the most common world map) greatly distorts (enlarges) the areas near the poles. See <a href="http://www.bobatkins.com/photography/technical/field_of_view.html">http://www.bobatkins.com/photography/technical/field_of_view.html</a> for a few more details on lens mapping and "distortion".</p>

<p>Distortion here isn't referring to lens aberrations that give barrel and pincusion distortion, or tilting lenses up or down which gives keystoning. The distortion that stretches objects at the edges of a wideangle rectilinear lens is intrinsic to the design of rectilinear lenses. It's a consequence of keeping straight lines straight. Even a perfectly corrected lens will show it.</p>

<p>Technically, Rectilinear wideangle lenses have a lot of volume anamorphosis (and keep straight lines straight), Fisheye lenses have little (but bend lines).</p>

<p>The "stretching" of objects near the edges of wideangle shots can be somewhat corrected using techniques known as volume anamorphosis correction. You can have cylindrical and spherical volume anamorphosis correction which correct the image in different ways. Which is best depends on the nature of the image you are trying to correct, but it's always a compromise.</p>

<p>If you got <em>really close</em> to a wideangle shot taken with a wideangle rectilinear lens, the perceived "streching" distortion would appear to go away, but we don't look at images that way.<br /> <br /> [<em>And just as an side here, please try to keep the snarky comments to a minimum</em>]</p>

<p>One of the advantages of being in my eighties is that I do not take umbrage at being called an antique becuase I don't like the distortion but that might change as I have s 7.5mm lens [ for MFT] on the way and I might just like the distortion it produces :-) Time will tell after it arrives in January and I get around to playing with it amongst all the other interests demanding my attention.</p>

<p>This has been a great discussion. Thanks to all. I started with looking at shots in the press that I would not have used two or three decades ago. I think non photogs do not notice this which is fine. Clearly the standards have changed. It is probably a good thing as it expands the photo vocab. </p>

I think lens designers for digital cameras are getting sloppy because in many cases they can depend on being bailed out by lens correction software like DxO and others. But the photographers/editors don't always bother to utilize such software.

<p>Charles, I take somewhat the opposite view, that lenses are better now than they have ever been. There has been a shift in recent years towards increasingly high resolving power, and that sometimes comes at a slight cost of distortion, but the distortion in most lenses is pretty mild. Consider my 12-24 Sigma, for instance. Even at 12mm, it's almost freakish how straight all the lines are!</p>

<p>Mark, you completely missed my point.</p>

<p>JC, maybe taking offense to being called an antique is more unique to women in their 50's, but I do take offense, very much so. It was a biting and cruel comment.</p>

<p>I would challenge anyone here to conduct a simple experiment: Take out your widest lens, and line up a group shot (horizontal orientation). Put your wife on either the far left or the far right. Then when she complains she looks FAT in the photo, tell her, "Honey, it's just your prune-like perception as an antique woman. The photo is fine." I wager there wouldn't be enough roses in all of San Francisco to erase THAT from her memory!</p>

<p>I don't like distortion, because I don't like making my subjects look stretchy and fat. My subjects don't like such things either, but they incorrectly blame such things on the lens, not the photographer, and they can't always even articulate the problem, beyond "I look fat in this photo."</p>

<p>To be perfectly clear, I made only three comments:</p>

<ol>

<li>lenses are getting wider with technological advances.</li>

<li>rectilinear distortion isn't really distorted with a certain viewing distance.</li>

<li>I don't personally care for distorted images.</li>

</ol>

<p>For these observations, I am labeled an "antique photographer" with "prune-like" views. I believe that's considered "name calling" by some, and if I were to have leveled these insults towards the moderator in question, I'd have been booted from the forum. And yet with our respective roles, there is not so much as an apology from the gentleman who insulted me. What's wrong here, and why should I stick around for such treatment?</p>

<p>I'm off to be with family now. Hopefully nobody calls me an antique! I'll be back Friday... or not. (I guess others will decide that for me.)</p>

<p> </p>

<blockquote>I think that this is becoming more accepted as time goes on.</blockquote>

<p>More accepted by active photographers who are aware of distortion? Or accepted by "average" viewers who are not photographers? I'd tend to agree about the former, but disagree about the latter. For the average viewer/reader, whether from 1933 or 2013, content is king. </p>

<p>I'm occasionally aware of it in just the sorts of instances that Errol Young mentions, but it doesn't really bother me. I'm far more inclined to be "bothered" by effusive praise and mass exposure for mediocre content than I am by any increase in photographs displaying lens distortion. I'm also probably more aware of fads in processing effects (used in advertisements, primarily) than lens distortion. For a while there seemed to be a flurry of ads which utilized selective focus/tilt shift effects, and a number of ads utilizing desaturation and high local contrast effects. </p>

<p>I suspect there was a post that was deleted before I viewed this thread. I have no idea what the "antique photographer" comments refer to. Probably just as well. If a photographer is an antique because they notice and are bothered by instances of lens distortion, then I am a lazy and ignorant "digital generationer" because I am not bothered or cognizant of an increased acceptance of lens distortion. Neither stereotype is fair or true. It's just another branch of the old film v digital, manipulation is cheating/not cheating, kind of arguments. </p>

 

<p>This is not a distortion in the lens. It is an effect of change in perspective, or more correct that image content do not change perspective when you change the viewing distance, but the real world scene that you captured will change perspective. So you might call it a perspective distortion, but the lens is not the culprit. It is the viewing distance when you look at the image after it is captured, developed and presented to you as a viewer.<br /> Think of it in this way: If you capture an image on a slide (a diapositive, so you can look through it) with a 300 mm lens, and you take the developed slide, that is the 24 mm by 36 mm slide, and hold it exactly 300 mm in front of your eye, and you stand at the exact same place as when you captured the image, then, if you look through the slide, the objects in the image will overlap the real objects in the scene exact. You have now the correct perspective when viewing the image. If you instead look through the slide at 50 mm distance, or 1 m, or any other distance than 300 mm, the objects in the image will no longer overlap the objects in the scene. You have a distortion of the perspective. The same goes if you look through the image at the initial 300 mm, but you now instead have enlarged the image, f. example made a 2 m x 3 m slide. The perspective will of course no longer fit. It is distorted.<br /> So, if you capture an image with a 10 mm lens on a 24x36 mm sensor, and you make an image that is 24x36 mm in size (exactly as large as the sensor), you have to hold that image 10 mm (the focal length) in front of the eye for the perspective to look correct. If you enlarge that image t0 24x36 cm (10 times the sensor size), then you have to hold that image 10 cm (10 times the focal length) in front of your eye for the perspective to look correct. Very few people do that, and very few people are able to view sharp at that distance even if they wanted to. So images from wide angle lenses are very likely to be viewed from a too long distance for the perspective to be correct.<br /> The opposite go for tele lenses. You probably will view the image from too short a distance, and you get what is often mentioned as distortion of the depth. If the above image was taken with a 500 mm lens instead of the 10 mm lens, and you enlarged the picture to the same 24 cm x 36 cm (still 10 times the sensor size), you would have to move 5 meter (500 mm x 10) back from the image for the perspective to be correct.<br /> All this is valid for ideal rectilinear lenses only (and pin hole cameras, but then you have to substitute the focal length with the distance from the whole back to the center of the film).<br /> Hope this was understandable. (and excuse my English, it is not my native language)</p>

<p>I don't care much about that fact as they are not my pictures. Not picture of me nor a picture that I took. But when I am in a situation where I have to accept some distortion with wide angle lens (because I can't back up any further) I am afraid of the person whose picture got flatten out would be unhappy. </p>

<p>If you use a swinging lens camera you won't get the stretching effect, though as far as I know there are no swinging lens digital cameras because they require a curved film plane and nobody as yet makes flexible digital sensors. However you will get the effect of straight lines being curved (unless you curve the print and view it from where the lens was with respect to the film!) You could also minimize the effect by taking a sweep panorama with a longer lens or by stitching together a few shots taken with a longer lens.</p>

<p>Tradition photographers and viewers may well be disturbed by the stretching of the image at the edges. More experimental photographers and artists my chose to use the effect deliberately</p>

<p>Traditional photographers and most "clients" don't like images which appear stretched at the edges. More experimental photographers and artists might chose to use the effect intentionally. There's no "right" and "wrong" involved.</p>

<blockquote>

<p>Traditional photographers and most "clients" don't like images which appear stretched at the edges. More experimental photographers and artists might chose to use the effect intentionally. There's no "right" and "wrong" involved.</p>

</blockquote>

<p>I mostly/usually agree, and I don't wish to belabor any points here, especially considering you have been very kind to patch up a very prickly thread. I merely want to point out that this line being drawn between traditional/antique/old/distortion-free and new/hip/modern/distorted is a false one. Also the line being drawn separating older photographers with their older styles and younger photographers with their more experimental styles is not always valid. It is an unfortunate stereotype, and it has been applied incorrectly to me.</p>

<p>Although I am an older photographer with a long trail of experience behind me, I am now, and have always been, a highly experimental photographer. I'm not talking about slapping wide angle lenses on my camera and saying, "Wow, distortion.... cooooool!" I'm not talking about using the latest photo app to shove somebody else's sliders around and make straight-up images look strange, grungy, or whatever. I'm talking about the continued pushing of technological and methodological envelopes. I'm talking about the development of new concepts. The irony of the "antique photographer" label is that my work is far more experimental than that of the (excellent) photographer who applied it to me. (The other irony is that I suspect I am not much older than he is.)</p>

<p>So I submit that someone who *generally* does not like the distorting effects of extreme wide angle lenses on people's faces and bodies (at least from a standpoint of bread-and-butter photography done for others) can actually be a very progressive photographer. For instance, most recently, I want Roger Cicala's 1900's B&L (Zeiss design) 5x7 Tessar, so I entered this photo in his PhotoGeek contest (yes, I'm a geek, and I own it), in the bokehliciousness category, in hope of winning it:</p>

<p>http://www.pbase.com/lensrentals/image/153148659</p>

<p>I don't think this is the work of an "antique photographer," and even a casual examination of my portfolio here (<a href="http://www.graphic-fusion.com/gallerysdf.htm">http://www.graphic-fusion.com/gallerysdf.htm</a>) will turn up several more experimental images. What can I say? I'm a scientist. I like to experiment. Oh, and what will I do with the lens if I win it? You guessed it: Experiment! (Wish me luck.)</p>

<p>But no, this nontraditional, experimental, experienced, somewhat older (but not "old," "antique," or "prune-like") photographer still does not like distortion effects on bodies and faces. (This is not to say I never like or use distortion, which I often do.) My preference is neither correct nor incorrect. It is merely my aesthetic preference which I am entitled to have. I believe the OP was asking how we felt about distorted images, and that's how I answered. That's all.</p>

<p>Finally, I appreciate everyone's patience and the opportunity to clarify these points about my work.</p>

"As well you can see that on renovation and real estate reality shows on the tube where the proportions of people's faces

change as the camera pans."

 

This particular manifestation has NOTHING to do with camera, technique, lens, or anything to do with the original

production. It is a peculiar thing that broadcasters use to stretch a show produced with a 4:3 aspect ratio (old "analog"

TV) onto a 16:9 (HDTV) signal and screen. Often called "Smart Stretch" it stretches the edges of the image out tithe

boundaries of the wider format screen, while maintaining the proper image at the center.

 

en.wikipedia.org/wiki/Widescreen_display_modes#Wide_Zoom_mode