[MadMathMind]

I was talking with another photographer and he said that he really dislikes shooting portraits below 85mm because "you get a distortion where it makes things closer to the camera look bigger, and things farther away look smaller." This is the first time I've ever heard that explanation.

He shoots full frame (Canon), so the equivalent on APS-C would be ~56mm. I've shot a lot below that and never noticed unacceptable distortion. I know 85mm (FF) is the sweet spot for portrait lenses, but is this why? The Pentax 50mm lenses are simply gorgeous for distortion-free photography. Could it be a Canon thing? I saw their 16-35's results and I was not impressed at all with the ridiculous distortion.

[Adam]

He might be referring to perspective distortion, since the lens would have to be closer to the subject. You should be perfectly fine at 55mm on APS-C, but imagine doing portraits at 20mm.

[MarkJerling]

I think different lenses will have different distortion characteristics. 16-35 is, of course, quite a wide angle lens and may well have quite a bit of distortion, depending on what you're shooting.

[fuent104]

The person you were talking to may be taking closer portraits than you are used to taking. If he's doing really close work, I can see how it would be unappealing. Having said that, it's all about preferences. Shoot with whatever lenses you like, and completely ignore information that doesn't help you. There's no benefit to wondering what you're doing is good according to what other people like.

---------- Post added 04-22-15 at 04:20 PM ----------

Also, I wouldn't described what he described as "distortion," but he's correct, objects in the background will be larger in the frame when you shoot with narrower fields of view.

I kind of wish that, throughout the history of photography, lenses would have been described in terms of field of view rather than focal length. I think it would have been a more productive way to refer to lenses. Maybe we could also know the focal length. Field of view is clearly the more relevant concept.

[MadMathMind]

He might be referring to perspective distortion, since the lens would have to be closer to the subject. You should be perfectly fine at 55mm on APS-C, but imagine doing portraits at 20mm.

Right. 20mm requires getting too close. I've done full body shots (costumes) at ~24-30mm. Those seem to come out ok. Doing them at 50mm requires being a mile away.

Classical portraits are waist up. We're looking to go a bit further down because our subjects will be dressed elaborately and the costume is very much part of the photo (the point of the photo, really). The Sigma 18-35 has been good for that, although I find it is a bit unforgiving on people. Either it misfocuses or its so sharp that its unflattering. And it's bokeh will be a bit more consistent. I think the FA31 Limited will fix a lot of that. And get me ready for FF!

For comparison, I shot this at 31mm and I don't see any of the effects he is speaking of:




I have noticed that short focal lengths are much less forgiving when it comes to angle. It's very easy to land in warp world if you're too far below or above the subject.

---------- Post added 04-22-15 at 05:50 PM ----------

The person you were talking to may be taking closer portraits than you are used to taking. If he's doing really close work, I can see how it would be unappealing. Having said that, it's all about preferences. Shoot with whatever lenses you like, and completely ignore information that doesn't help you. There's no benefit to wondering what you're doing is good according to what other people like.

I agree. I was just wondering if I was missing something.

What I dislike about the 50mm is that it requires being rather far away if the goal is more than a head and shoulders portrait. The FA77, while otherworldly awesome, requires really being far away.

[stevebrot]

I was talking with another photographer and he said that he really dislikes shooting portraits below 85mm because "you get a distortion where it makes things closer to the camera look bigger, and things farther away look smaller." This is the first time I've ever heard that explanation.

As noted above, it is not distortion, it is simply perspective and results from being close to the subject. This is easily demonstrated by taking two photos from the same distance, one with a normal or wide lens and the other with a traditional portrait length. Crop the wider image to the same composition as that from the portrait lens and marvel that they have the same relatively flat perspective.

FWIW, for head/shoulder portraits, you can go as short as 35mm on APS-C with no appreciable exaggeration of near features.

The below was taken with the FA 35/2 on the K10D and was cropped about 5% from the original framing.




Steve

[Blue]

I was talking with another photographer and he said that he really dislikes shooting portraits below 85mm because "you get a distortion where it makes things closer to the camera look bigger, and things farther away look smaller." This is the first time I've ever heard that explanation.

He shoots full frame (Canon), so the equivalent on APS-C would be ~56mm. I've shot a lot below that and never noticed unacceptable distortion. I know 85mm (FF) is the sweet spot for portrait lenses, but is this why? The Pentax 50mm lenses are simply gorgeous for distortion-free photography. Could it be a Canon thing? I saw their 16-35's results and I was not impressed at all with the ridiculous distortion.

He could just be full of it . . . he is shooting Canon.

[MadMathMind]

He could just be full of it . . . he is shooting Canon.

As much as I like to take shots at Canon, I happen to like this guy's work, so I'm listening when he says something.

[clackers]

As much as I like to take shots at Canon, I happen to like this guy's work, so I'm listening when he says something.

He might be a great practitioner, but that's misleading advice he's dispensing, MadMathMind.


You can look and admire his work, you don't have to absorb his opinions too.

[VisualDarkness]

He is correct when it comes to perspective, it changes with focal length. The shorter the FL the more exaggerate objects closer to you and longer lenses instead gives a flattening perspective. It's all a matter of taste and if he knows what he likes and how to get it, kudos to him.

[MadMathMind]

He might be a great practitioner, but that's misleading advice he's dispensing, MadMathMind.


You can look and admire his work, you don't have to absorb his opinions too.

I said I was listening, not believing. That is why I opened this thread--Detective M^3!

[lytrytyr]

The Sigma 18-35 has been good for that, although I find it is a bit unforgiving on people. Either it misfocuses or its so sharp that its unflattering. And it's bokeh will be a bit more consistent. I think the FA31 Limited will fix a lot of that.

An original concept, using an FA 31 to fix the unflattering sharpness of a Sigma!

[Lowell Goudge]

I was talking with another photographer and he said that he really dislikes shooting portraits below 85mm because "you get a distortion where it makes things closer to the camera look bigger, and things farther away look smaller." This is the first time I've ever heard that explanation.

He shoots full frame (Canon), so the equivalent on APS-C would be ~56mm. I've shot a lot below that and never noticed unacceptable distortion. I know 85mm (FF) is the sweet spot for portrait lenses, but is this why? The Pentax 50mm lenses are simply gorgeous for distortion-free photography. Could it be a Canon thing? I saw their 16-35's results and I was not impressed at all with the ridiculous distortion.

What he is talking, although commonly referred to as perspective distortion, is actually nothing to do with "perspective" at all. what the distortion is all about is magnification ratio.

consider, that lens magnification, in simple terms is the following

Magnification = Image size / Subject size = focal length / distance

OK for all the purists there is a secondary term which becomes important if you are closer than 10* the focal length, but we will forget that term for now because you are always shooting beyond that range unless you are really. really close.

What you can see, is that magnification is inversely proportional to distance. So anything that is closer to the lens gets magnified more, things further away get magnified less. Of course, when you are far away, the impact is much less because the change in distance has little impact on overall magnification between different parts of a subject.

now lets consider taking a portrait, lets , for fun, say it is head and shoulders shot. so the subject is likely 30cm high.

you shoot with an 85mm lens, and you fill a vertical full frame, 36mm

to do this requires magnification = 3.6/30 = .12 and your working distance is 708 mm.

now, lets consider your subjects nose, which the tip of could be 25 mm (really big nose?) closer or 683 mm from the lens. its magnification is .124 or not quite 4% larger in proportion to the rest of the face. OK not so bad, 4% is really not that much.

Now, lets consider the same shot, but with a 35 mm lens, but retaining the same fill on the frame.

to get the same framing i.e. magnification on the sensor, you now move to 269mm from the subject. but their nose is now 244mm away, and the resulting magnification on the nose is .143 or almost 20% larger in proportion than the rest of the face.

this is what the discussion is all about. The shorter the focal length, the nearer you need to be to a subject, and the higher the apparent distortion due to the difference in magnification of the near and far features.

Shorter and longer lenses don't have different perspectives when shot from the same distance either, an 85 mm shot is just a crop out of a 35mm shot from the same distance. it is moving closer that gives "perspective distortion" because now you change the magnification ratio of the relative parts of the frame.


This same principle is what leads to barrel distortion and the bending of straight lines in fisheye lenses. as you move to the edges of the frame, the subject is further away from the lens, so the subject is magnified less.

Now lets apply barrel distortion correction to a wide angle lens, to correct for barrel distortion really means that things futher off center get magnified more so that you get straight lines of rectangular objects, now put parts of a subject, with a wide angle lens (again the nose is a good example) toward the edge of the frame, and it gets magnified even more than the central part of the subject, so the 25mm nose again gets really big in a hurry. For portraits with wide angle, you might actually want some barrel distortion to get more flattering shots.

[Tanzer]

Wide angle lenses can be used to make women's legs look longer when shot from close to the ground, and men's shoulders look broader when shot from slightly above. So the perspective thing is very real, but whether it is a problem or not depends on who your subject is, and what (face, head/shoulders, 3/4 body, or full body) you are shooting.

He shoots full frame (Canon), so the equivalent on APS-C would be ~56mm.

Hence, the DA*55mm f/1.4 portrait lens.

[Sagitta]

I use my Sigma 10-20 for portraits (OK, maybe not portraits, but 'people snaps') every once and a while. As long as you don't have the subject towards the edges of the frame, distortion isn't a big deal with it. Sometimes the distortion can actually be used for effect. I certainly would avoid using the thing at 10mm for the same job, though.