Range of focal lengths for an RB Auto

Sirius Glass · Jun 13, 2010

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 · Jun 13, 2010

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 · Jun 13, 2010

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 · Jun 13, 2010

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 · Jun 13, 2010

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 · Jun 13, 2010

erikg said:
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 · Jun 13, 2010

mopar_guy said:
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 said:
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

removed account4 · Jun 13, 2010

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

jon koss · Jun 13, 2010

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

Sirius Glass said:
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 · Jun 13, 2010

15 inches sounds interesting.

Steve

brian d · Jun 13, 2010

What jon said, I have a 3x4 RB auto waiting to be fixed up. I tried a 162 enlarging lens on it and it wouldnt quite focus to infinity

leighmarrin · Jun 14, 2010

I've tried a 127m/f4.7 Ektar on my non-auto Series D 3x4 graflex. As I recall, it had a limited focus range of about 1 to 4 feet.

removed account4 · Jun 30, 2010

Sirius Glass said:
15 inches sounds interesting.

Steve

i finally got a chance to fake a lensboard
and stick a 10" and a 15" tele raptar on my series D ( 4x5 )
the 15" works fine, i had it on a speed graphic lensboard
not even as far back as it needed to be ( the placement with
the series d lensboard ) ... it focused at infinity and was nice
at close and medium distances ... the 10" ... well, it needs the equiv.
of a recessed lensboard to focus at infinity, but it would be fine for
portraits and non -infinity photographs.

john

marcbanka · Jul 14, 2010

Jon,

I use a 4x5 auto graflex often (great camera) with a 10 inch Raptar most often. It came with somethiing around an 8 inch which does reach infinity. The 15 inch tela-raptar is nice for close headshots. For the softer older style I have a 10 inch Veritar and an 8 3/4" verito that give interesting results. Fun.
As I'm sure you know, the camera was intended to be hand held, but I've found the recoil from the mirror slap is enough to effect sharpness. I heavy tripod fixes the problem, but to keep it portable I use it with a monopod, when out and about. It give enough support to prevent the camera from "jumping" when the shutter is released.

Marc

Range of focal lengths for an RB Auto

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