Distortion in Portraits with Nikon D300?

[anonymous]

I have a question that I haven't seen answered anywhere on the Web. I thought that maybe someone here would have an answer. It's a very practical question in fact, since it clearly affects my photography in the field.

I just bought a Nikon D300 with a 50mm 1.8 lens and an 85mm 1.8. When I did a portrait of my wife in landscape orientation (the usual for the camera), her face seems a bit larger than life, a bit stretched on the horizontal and less long in the vertical axis. When I rotate the camera in portrait orientation, she seems thinner than usual. I tried to keep the same distance for the two situations but it always does this strange effect. Of course, she likes looking thinner, but I was wondering why I can't make her look natural with the normal orientation of the camera. Is there a physical reason to that ? The effect seems worse with the 50mm than the 85mm. I put her face on the left side of the picture for a better composition while in landscape orientation. My distance to the subject is about 1 meter to 1.5 meter and a half with the 50mm, just enough to have only her face in the picture while in landscape orientation.

Thank you very much and please excuse my English, I'm a french native.

[McQ]

Other than a difference in distortion between lenses (which I believe is negligible with both these models), the primary cause of this observed difference ought to be from "perspective distortion." I put this in quotes because in some sense it is not really distortion as one would ordinarily think of it.

The key here is that one would have to get a little closer in portrait orientation to get the face filling the frame-- thereby exaggerating the perspective. This website gives an example of perspective exaggeration using two interactive diagrams on the page about understanding camera lenses and focal length.

This would also be consistent with your observation that it is worse with the 50mm lens. If one were to try a 35mm lens this effect ought to be even worse (the wider the lens the more perspective distortion). 135mm should eliminate this almost entirely. In your case, though, the 50 and 85mm are not normally considered wide angle lenses, but the effect is there with all lenses-- just to a *much* less pronounced degree with telephoto lenses. Hope this helps.