Portrait perspective issues investigated

[Old-N-Feeble]

Perspective distortion is a matter of distance from lens to subject. It doesn't matter what film format, provided the same ratio, e.g. 1:1.25. It doesn't matter what lens focal length other than acquiring the desired angle of view. For head-and-shoulders portraits most folks seem to prefer 2x-3x focal length so for 135 film, cropped to 1:1.25 ratio, thats a 85-135mm lens. For 4x5 format that's a 300-450mm lens. This is if the subject is framed closely and the image isn't cropped during enlargement. Of course, this begins to become impractical fairly quickly so one will probably need to compromise much of the time.

Regarding print viewing distance being a major factor in how one lens focal length appears vs. another: My personal opinion is that's largely bunk. I don't care how closely I view a print (within reason) of a portrait taken with a lens that's far too wide the image looks distorted.

[Mark Barendt]

Perspective distortion is a matter of distance from lens to subject.

No.

That is an urban myth based on a fairly arbitrary tradition of viewing distance.

Essentially I believe this tradition comes from viewing prints hand held.

Pick up a 2x3 print and you'll probably hold it pretty close (given average subject matter), 4x6 not quite as close, 5x7 bit further, 8x10 further again, and so on. I think the root of "normal" came because "normal lenses" made prints looked normal hand held.

That "standard of normal" isn't a technical standard, it's a variable, it's a tradition.

[Old-N-Feeble]

I disagree, Mark. What I stated is "most folks prefer" and this is true for the most part. Nearly anyone will agree that a head-and-shoulders portrait shot with a lens of .5x FL instead of a lens of 2x FL (neither cropped during printing) will look extremely distorted no matter what viewing distance.

[Mark Barendt]

Print that wide angle shot 30"x40" and hand hold the print yourself to view it and you may get surprised.

[Old-N-Feeble]

Print that wide angle shot 30"x40" and hand hold the print yourself to view it and you may get surprised.

Most folks don't view a 30x40 inch print at 18 inches. Some do but 'most' don't.

[Mark Barendt]

I agree that most don't.

It is though the reason that there is visible distortion, the wide angle look is because people don't normally print wide angle shots big enough for the viewing distance that the print will be seen at.

What I'm suggesting though is that we can apply this principle to make our prints look better to the observer. If all we have is a 150mm lens for our 4x5 but we like the look we have seen with 210mm lens on a 4x5 then we might just want to enlarge a bit more when printing. You are right in suggesting that if the distance to the subject is constant the perspective the camera remains. If we keep the same size paper the cropped print from a 150mm lens mimics the un-cropped 210mm lens print almost perfectly. This assumes the prints are viewed from the same distance.

What changes when we change focal length lenses is the magnification and angle of view. The magnification can be adjusted when printing. We can also make a bigger print from a wider angle lens (by not cropping to match the view of the 210 in this case) and have the subject/face remain the exact same size just have more context around the edges.

The distortion only comes when we change the viewing distance to the print.

[Ulophot]

This has been, for me, a fascinating discussion, covering in considerable depth the subject of print viewing distance, which certainly is a factor. Given the many the variables of the process from photographing to displaying, it seems to me to be something one should bear in mind but, with all due respect to Mark's and others' precision, somewhat broadly.

Reviewing Ansel Adams's later series of books a week ago in the course of pondering various LF considerations for future portraits (I am, regrettably, still not able to re-engage in actual film photography), I came across his portrait of Brassai (The Camera, pg 112) taken with the normal, 80mm lens on a Hasselblad. In the caption he states that he had moved in fairly close "but not enough to cause distortion," and that he cropped the negative somewhat in printing. The face fills about 2/3 of the print vertically, so he was indeed pretty close.

This led me to run a quick series of self-portraits with a digital video camera so that I could compare frame-grabs side by side, with the camera at 5, 7, and 9 feet. The results were instructive, so I will indicate my procedure for any who might wish to replicate the experiment in one medium or another. I simply sat at a table with hands folded about a foot in front for a frontal shot series. Leaving one arm on the table, I turned about 45 degrees and looked back toward the camera a t a slightly lesser angle, for a second series. I used the zoom lens to take each pose at each distance twice: one including hands and head, one zoomed in to a head shot.

The differences in the drawing, or perspective, are appreciable in all the frames. For the kinds of portraits I have in mind to make (see original post), I shall tend to stick with the longer distances. However, I have learned from this exercise more about the means of using perspective that may be applied with subtlety on one or the other subject. Hence, my view towards using my one 4x5 lens, the 210mm, for closer framings has widened.

[Alan Gales]

These may help you.

http://mcpactions.com/2010/07/21/the...rs-experiment/

http://digital-photography-school.co...n-portraiture/


I remember when I started in photography back in the early 1980's with a 35mm camera. Everyone said for a close portrait you needed an 85 to 135mm lens. I was taking a portrait of my then girlfriend in my car. My 100mm lens was too long to use in the cramped space so I used my 50mm. The photograph came out great and everyone commented on how pretty my girlfriend looked in the photograph.

You can get away with a normal lens up close if you are careful but it is easy to get distortion like large noses. A longer lens is better. How long depends upon your taste.

[Old-N-Feeble]

Alan... Did you crop your girlfriend's portrait to 8x10 format? If so, a 'normal' lens for 24x30mm film being 38mm... and assuming you printed the full frame width... and the 50mm lens you used was indeed precisely 50mm FL, then that was like shooting a 201mm lens on a 4x5 camera. If you cropped the width a tiny bit (most likely) then it was probably closer to 210mm on 4x5. Many so-called 'normal' 50mm lenses for 135 cameras are up to 3mm longer than 50mm. So... if you cropped to 8x10... and cropped the short side a tiny bit... and your 50mm lens was really a 53mm lens... then that would have been like shooting with a 225-250mm on 4x5.

Was that a waist up shot, head-and-shoulders or face close-up?

[Alan Gales]

The shot was not much more than head and shoulders. I shot it with a 50mm f/1.7 Zeiss lens on my Contax. The original print was printed at 3x5? Wasn't that the size before 4x6 became popular? I also had a 5x7 enlargement made.

We were in my 1973 Dodge Dart Sport front seat so we were pretty close.

Man, 3x5 prints and a Dodge Dart. That was a long time ago! I remember when 4x6 was called super size and you had to pay extra. The only reason I remember the shot was because I broke the so called rules and learned something.

I will say this. My girlfriend was pretty but she was extremely photogenic.