Range of focal lengths for an RB Auto

[Sirius Glass]

Now that I found a source for Graflex A boards, I am wondering what is the range of focal lengths for a 3.25" x 4.25" RB Auto Graflex? I have a 7 1/2 inch lens [190.5 mm] and I wonder if I could use

• a 90mm lens with the drop front,
  a 127mm,
  a 135mm.

I am concerned that a short focal length lens could interfere with or damage the mirror.

Which are the longest lens practical for this camera, while holding the camera.

Steve

[Fotoguy20d]

Steve,

I believe the standard lens for that camera is something in the 6-7" range. I don't think you can go much shhorter than that. My Series D in that size has a 6 3/4" Kodak Anastigmat. I think that's equivalent to a #32. The Auto Graflex I recently picked up is a 4x5 - from my reading, you can't use anything shorter than about 190-200mm with it.

Dan

[mopar_guy]

From Graphic Graflex Photography Ninth Edition by Morgan and Lester:

Chapter 26-Equipment
Page 381

"The 3-1/4 x 4-1/4 model with bellows capacity of 15 1/2 inches and a lens board measuring 3-1/4 inches square accommodates lenses with focal lengths from 7 to 17 inches. 7 1/2 inch lenses are considered to be standard and are usually supplied with this model."

To answer your question, shorter focal length lenses of standard design will interfere with the mirror when focused at infinity. Steve, one thing to remember about the mirror is that it is probably a front silvered design and the coating will probably be quite fragile. Do not try to "clean the mirror" by wiping it with anything. You would probably destroy the coating.

[erikg]

Nothing much shorter than a 150, 152mm really, but it depends if you need to focus to infinity. You can try one out and see when the mirror bumps, you can do this slowly, but the mirror isn't so delicate. Longest? Maybe a 250, depends on how steady you are.

The RB Auto doesn't have a front silvered mirror, unless it was upgraded at some point.

[Sirius Glass]

Dan,

Thank you. I have had a suspicion that would be the case. Kodak/Folmer & Schwing would have offered shorter focal lengths if it were possible. I think that the 7 1/2" lens will be good for both portraits and landscapes.

Steve

[mopar_guy]

Nothing much shorter than a 150, 152mm really, but it depends if you need to focus to infinity. You can try one out and see when the mirror bumps, you can do this slowly, but the mirror isn't so delicate. Longest? Maybe a 250, depends on how steady you are.

The RB Auto doesn't have a front silvered mirror, unless it was upgraded at some point.

If I remember correctly, all Graflex SLRs made after about 1937 have front silvered mirrors.

[Sirius Glass]

From Graphic Graflex Photography Ninth Edition by Morgan and Lester:

Chapter 26-Equipment
Page 381

"The 3-1/4 x 4-1/4 model with bellows capacity of 15 1/2 inches and a lens board measuring 3-1/4 inches square accommodates lenses with focal lengths from 7 to 17 inches. 7 1/2 inch lenses are considered to be standard and are usually supplied with this model."

To answer your question, shorter focal length lenses of standard design will interfere with the mirror when focused at infinity. Steve, one thing to remember about the mirror is that it is probably a front silvered design and the coating will probably be quite fragile. Do not try to "clean the mirror" by wiping it with anything. You would probably destroy the coating.

Nothing much shorter than a 150, 152mm really, but it depends if you need to focus to infinity. You can try one out and see when the mirror bumps, you can do this slowly, but the mirror isn't so delicate. Longest? Maybe a 250, depends on how steady you are.

The RB Auto doesn't have a front silvered mirror, unless it was upgraded at some point.

The difference between ~6" and ~10" does not seem to make it worth it to get more lenses.

After I have used this camera a lot I will consider a 4x5 with more movements, but this one will always be special.

Steve

[jnanian]

you can use longer lenses
like the 10" and 15" tele optars

[jon koss]

Hi there Sirius - The constraints on minimum focal length are pretty much set by the physical layout of the camera. The distance from a fully racked in lensboard to the film plane is something like 165mm, so anything much shorter just won't rack in enough to achieve infinity focus. A 127mm specifically will definitely focus at something like a foot or two, but won't reach infinity. I am assuming that there is no such thing as a large format retrofocus wide angle, but other APUGers will know better than I do. Hope that helps.

Jon

Now that I found a source for Graflex A boards, I am wondering what is the range of focal lengths for a 3.25" x 4.25" RB Auto Graflex? I have a 7 1/2 inch lens [190.5 mm] and I wonder if I could use

• a 90mm lens with the drop front,
  a 127mm,
  a 135mm.

I am concerned that a short focal length lens could interfere with or damage the mirror.
Which are the longest lens practical for this camera, while holding the camera.
Steve

[Sirius Glass]

15 inches sounds interesting.

Steve