View Full Version : Lensboard tickness for Nikkor 75 f4.5

Bernard Languillier
20-Oct-2004, 21:15
Dear all,

I have just gotten a new Ebony view camera and am trying to set it up.

I bought a second hand Nikkor 75 mm 4.5 and intended to fit it on an Ebony lensboard (Linhof standard).

For some reason, it seems that the lensboard is too thin compared to the gap between the rear and front elements of the Nikkor.

Even when the regular ring shaped spacer is in place on the rear thread of the front element, there is still at least 1 or 2 mm of gap around the lensboard after the rear element is fully screwed on. The lens is therefore not firmly held in place and ends up being unstable and off axis.

I was wondering if someone else had similar experiences with the Nikkor 75, and if there was a known remedy for this issue? I have no such problems with a new Nikkor 300 M mounted on a similar lensboard (with #1 hole of course).

Thank you in advance,

Best regards,

Graeme Hird
20-Oct-2004, 22:48
I'm not familiar with the particular lens, but the flange on my lenses has a stepped profile. If I put the flange on backwards, I get the problem you are describing.

Have a look at the flange on your lens (meaning the threaded ring that holds the lens to the lens board) to see if yours is similar.


ronald moravec
21-Oct-2004, 05:33
You could also try making washers from mount board or other material. They can be square with a hole the size of the shutter. Some felt from a fabric store could be glued the board to form a cushon or light seal.

Gem Singer
21-Oct-2004, 05:53
Hi Bernard,

Assuming that you are using a genuine Ebony lensboard, and since Ebony lensboards are factory milled for Copal 1 and Copal 0 shutters they are very accurate, double check to make certain you are using the proper sized lensboard for your Copal 0 shutter. Second, make sure that you have removed the tiny index screw from the back of the shutter. Finally, check to see that the retaining ring is facing so that the spacing ridge fits into the hole along with the threaded portion of the shutter that holds the rear element of the lens. Play around with it while tightening to make sure it completely fits onto the hole before giving it the final tightening (that is easier to do than to describe in words).

If all else fails, find a local camera tech to mount your lens and shutter and/or show you how to do it yourself.

Dan Baumbach
21-Oct-2004, 14:09
I have a 75mm Nikkor mounted in a Shen-Hao lensboard with is also Linhof size and it fits perfectly.

Great lens, BTW.

- Dan.

Bernard Languillier
22-Oct-2004, 18:58
Hello all,
Thanks again for your help. It seems that I found a solution.

I was under the impression that the black L section shaped spacer ring on the rear of the front element had to be screwed all the way, which caused the issue.

I tried to only screw it half way, leaving some gap between it and the rear flange of the front element. Thanks to this, the lensboad now fits well between that spacer and the cylindrical body of the rear element. I am not sure if it is how it is supposed to be, but well, it seems to work.

The only concern with this is the following: the rear element might not be screwed down all the way with this assembly method. Can the lens be focused perfectly even if the rear element is posisitioned a few tens of a mm too far to the back compared to the front element/shutter?

Thank you in advance,

Best regards, Bernard

Ernest Purdum
22-Oct-2004, 19:11
Bernard, the lensboard should go beween the ring and the shutter. There may be a tiny screw protruding from the back of the shutter. If there is, the lensboard needs to be notched or drilled to clear this screw. (Some people remove the screws, but I think it is better to go to a little trouble to keep it. It keeps the lens assembly from twistingf on the lensboard. ) The rear element should screw all the way in freely.

Michael Mutmansky
22-Oct-2004, 19:21

It sounds like you don't have the lens mounted correctly.

Unscrew the rear lens cells from the shutter. Does the lens come off at this point? If so, you have it on incorrectly.

The front lens cells and shutter should be mounted on the board solidly by a threaded collar. Take the shutter and unscrew the threaded collar from the rear of the shutter. Put the shutter in the board hole and screw the collar back onto the shutter. Screw it down tight, and it should clamp down on the board, holding the entire assembly solidly on the board. Then, screw the rear cells back onto the shutter until it is finger tight.

It is important that the front and rear elements be properly spaced, and the lensboard will not interfere with this spacing if the lens is mounted properly.

Some shutters may come with a very small registration screw mounted on the back of the shutter that is intended to go in a hole in the lensboard to keep the lens from rotating on the board. If the shutter has that screw, it will not mount correctly to a board unless the board has the hole to mate with it. Most boards don't have the hole. You can use a very small screwdriver to remove this registration screw if it exists.


Bernard Languillier
25-Oct-2004, 02:16
Thanks a lot for your help, it's finally clear to me!

Best regards,