Hole position on lens boards for Chamonix 4x5

[Greg]

I have always just center the lenses on my 4x5 Chamonix by eye. All my lenses more than cover the format and 100% of what I shoot with the camera is nature ranging from abstract to "f/64", not requiring precise centering of the lens. Have accumulated 9 different Linhof type lens boards over the years. I always knew that the holes in the lens boards were never centered and varied in their up or down position. So today thought I'd measure where the holes were in my boards. All the boards were purchased with pre cut holes to fit the shutters. So what I did was to measure the distances from the center of the hole to the bottom of the lens board. Measurements probably accurate to + or - 0.05mm. Here's what I found:

4.8 or 4.75cm (to close to call) OEM Chamonix board with factory drilled hole

4.2cm WISTA board
4.25cm generic high quality board
4.5cm recessed high quality board
4.75cm generic board
4.75cm WISTA board
5.225cm WISTA board
5.25cm generic board

So the position of the holes varied by 1.2cm. When I visually center the lens on my front standard, I probably am within less than + or - 0.4cm of the lens being on center which totally works for my photography. On both sides of my front standard (45N-2) are 2 dots 2mm apart, lower one painted in red, and the upper one unpainted in. The OEM holes in my Chamonix boards are, and probably probably not just coincidently, 2mm off the center of the board. I used the red dot to align my OEM Chamonix boards. I had assumed that the unpainted dot was for OEM Linhof or even WISTA boards.

Hugo, am I right in using the red dot with my OEM Chamonix boards?

What surprised me was that the holes in my 3 WISTA boards were all in different locations. I had assumed that they were all equally off center.

My original intent was to confirm that my off center boards were all equally off center from the OEM lens holes on my Chamonix boards, and then use the unpainted alignment dot for all the non OEM Chamonix boards. Boy was I wrong. Now I seriously considered to replace my non Chamonix boards with OEM Chamonix boards, but at $75.00 each, hard to justify that expenditure. Since my visually centering the lenses has worked for me so far, will probably just keep doing the same.

Comments welcome....

[Keith Pitman]

Don’t obsess about it. Just adjust the rise/fall where it needs to be for the image you want to make.

On the other hand, if you have money to burn, you can buy new boards and, like Goldilocks, get everything just right.

[xkaes]

This issue has been discussed on this Forum before. You are correct, holes seem to be placed all over the place. A lot of the time this is not too critical because the image circle of the lens is large enough. But it is best to get the center of the lens in the center of the ground glass. This is where the sharpest part of the image is, and it gives you the most movement possible. And with lenses that have smaller image circles it is critical to avoid vignetting of the corners.

Different cameras are structured to have lensboard holes in different places. Most don't tell you where, but you can figure it out yourself -- I had to. For my cameras it is 10mm off center on a Toyo board. Do a search for this issue and you should be able to find the previous discussions on this matter.

You are not alone.

[Hugo Zhang]

Greg,

You should use the white dot. We had the red dot on some of of our older models. It was designed for some accessories that have never come out. So ignore the red dot.

Hugo

[Doremus Scudder]

Geez, one would think that manufacturers would let us know what the spec is for their particular camera design regarding lensboard hole placement(s). Thanks to Hugo at least for clarifying which centering mark to use. However, it would be nice to have the exact offset the camera is designed for too.

It would also be nice to have a data base for Linhof, Wista, Tachihara, et al. that use "Technika boards," but seem to not have the same center hole placement. Heck, I don't even know if all Technika boards have the same center-hole placement.

Is there a way to know what boards fit what cameras, or are we on our own here?

Doremus

[xkaes]

You can't rely on the alignment dots alone. All that does is get the front standard to where the manufacturer of the camera placed it. PLUS, this does not necessarily mean that the manufacturer used a board with a hole in the middle of the board (however you define that) to set it. AND because the center of the hole on the board varies -- i.e. can be different from the center of the board -- the hole may or may not be in the same place as where the manufacturer set it. As a result of this plate of spaghetti, it's best to figure it out for yourself.

You want the lens centered on the center of the ground glass for reasons previously mentioned. When it is, chances are it won't be centered on the board -- even when the alignment marks are matched.

Over time, I've bought boards with holes "centered" in different places -- just like Greg found. More often than not, the seller doesn't tell you where it is centered or how much off-center it is. With my 47mm and 105mm, the image circle is so small I have to get it smack-dab in the middle of the ground glass. If you have a similar lens with a small IC, that's one way to find your "sweet spot". You don't even need to focus the lens. Put it on the camera and move it as close to the GG as possible. Is the center of the fuzzy image in the middle of the GG?

[GG12]

Often wondered why these holes were off center. I guess its because those having cameras with fixed front lens boards would use them (and rotate) to get the movement they wanted, up to a limited amount. Or if the front mount was offset, use an offset board to compensate. In hindsight, either seems clever or a bit odd.

[Two23]

Does this really matter? I almost always end up using a bit of rise anyway.


Kent in SD

[xkaes]

Does this really matter? I almost always end up using a bit of rise anyway.

With my 47mm and 105mm, the image circle is so small I have to get it smack-dab in the middle of the ground glass. Otherwise, at least two of the corners are black. And just as important, the center of the image circle has the sharpest result, so you want that to be in the center of the film.

[Bob Salomon]

Often wondered why these holes were off center. I guess its because those having cameras with fixed front lens boards would use them (and rotate) to get the movement they wanted, up to a limited amount. Or if the front mount was offset, use an offset board to compensate. In hindsight, either seems clever or a bit odd.

Linhof Technikas have lots of front movement and their holes are off center on the board so that the optical center of the lens is centered on the center of the film when all front and back movements are at 0. So your guess, in this case, is wrong.