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JRCriton
4-May-2013, 09:09
I was wondering if any one knew what the effect would be if I only used the rear element of this lens to shoot with? I've been looking for about 2 hours for an answer and I can't find one. I took off the front element and looked through the camera last night and I was still able to focus with just the rear element. What are the disadvantages also of just using the rear element to shoot with?
Thanks you for your time.
Sincerely,
JRC

xya
4-May-2013, 10:24
obviously this is a rodenstock geronar made for calumet. it's a triplet, which is the simplest design that can correct all aberrations. so if you take away one lens, it would show aberrations.

E. von Hoegh
4-May-2013, 10:44
Those Rodenstock Geronars are probably the best triplets ever made.
Depending on which diagram you look at, the rear element is either a plano convex with the flat side toward the aperture, or a double convex with the longer radius toward the aperture. The other two elements are in the front cell. So, you'd get an image similar to the image given by a magnifying glass of an equal focal length. Try it, you may like it.

JRCriton
4-May-2013, 20:51
Those Rodenstock Geronars are probably the best triplets ever made.
Depending on which diagram you look at, the rear element is either a plano convex with the flat side toward the aperture, or a double convex with the longer radius toward the aperture. The other two elements are in the front cell. So, you'd get an image similar to the image given by a magnifying glass of an equal focal length. Try it, you may like it.


So kind of the effect someone would get with a soft focus lens?

polyglot
4-May-2013, 23:19
So kind of the effect someone would get with a soft focus lens?

Soft focus generally implies that there is a soft image overlaid with a sharp image - you can still see plenty of detail through the haziness. A single element will have significant aberrations (unless you stop way down), so the image will be just softness with no really sharp bits.

Have a look at some of the meniscus-lens examples and expect probably slightly worse.

E. von Hoegh
6-May-2013, 07:13
So kind of the effect someone would get with a soft focus lens?

No, not really. Soft focus lenses typically get their look from uncorrected (or variable) spherical aberration. By using the rear glass alone, you'll leave all of the aberrations uncorrected - chromatic, spherical, coma, astigmatism, and etc. - although with the stop in front of the remaining element, distortion will be somewhat reduced. As I said, about like a magnifying glass.

JRCriton
6-May-2013, 19:36
No, not really. Soft focus lenses typically get their look from uncorrected (or variable) spherical aberration. By using the rear glass alone, you'll leave all of the aberrations uncorrected - chromatic, spherical, coma, astigmatism, and etc. - although with the stop in front of the remaining element, distortion will be somewhat reduced. As I said, about like a magnifying glass.

Okay. Thank you. I think I'm going to play around and see what happens.