Adjusting tabs to hold lens board on Chamonix 45 N-2

[Bernard Kelly]

Is there a way to make the tabs on the front standard of a Chamonix 45 N-2 a little more accommodating? They barely grip the (non-Chamonix) lens boards I have. As thin as they are, they're not thin enough, evidently.

[Bernard Kelly]

I have to assume the answer to the question is no. And, of course, a week ago a lens and lens board did fall off the camera because the tabs weren't fully closed.

The remedy seems to be twofold: shop wisely and file down the edge of the board that doesn't fit.

A complete thread on the subject (which I only discovered now) is here:

https://www.largeformatphotography.info/forum/showthread.php?41614-Be-careful-with-your-Chamonix-lens-board-locking-tabs

So I'm ending mine.

[xkaes]

Lensboard thicknesses vary. I've got one that's thicker than all my others, and it's a real tight fit -- oddly enough -- on ONE of my cameras. I would get rid of it, but it's a recessed board and they are pretty expensive. I'm able to fit it with some elbow grease, but someday I'll find the time to file down the edge -- just a bit.

[Alan Klein]

Email hugo zhang <hugoz_2000@yahoo.com> at Chamonix with your problem.

[Bernard Kelly]

It was Hugo who brought attention to the problem back in 2008 (see thread referenced above).

My camera was manufactured in 2021. So there's been no change in tolerances.

And it's true lensboard thicknesses vary enough to hinder the tabs sometimes. Back then, one could rely on certain vendors for boards that fit. Those options don't seem to be available any more.

So one has to rely on luck (as many did then) or filing the edge down (as I plan to). Or buying a Chamonix board. (Which might well be the best solution for some, in the end.)

[Alan Klein]

It was Hugo who brought attention to the problem back in 2008 (see thread referenced above).

My camera was manufactured in 2021. So there's been no change in tolerances.

And it's true lensboard thicknesses vary enough to hinder the tabs sometimes. Back then, one could rely on certain vendors for boards that fit. Those options don't seem to be available any more.

So one has to rely on luck (as many did then) or filing the edge down (as I plan to). Or buying a Chamonix board. (Which might well be the best solution for some, in the end.)

That's what I did when I bought my Chamonix 45H-1. I spent my money on new Chamonix boards. I didn't want to deal with someone else's problem of light leaks, mechanical intolerances, proper fit, etc. of used boards from other manufacturers. Plus the Chamonix boards are made from the same wood, aluminum and carbon fiber as the camera and look great together. They're very light, an added benefit.

[Kiwi7475]

It was Hugo who brought attention to the problem back in 2008 (see thread referenced above).

My camera was manufactured in 2021. So there's been no change in tolerances.

And it's true lensboard thicknesses vary enough to hinder the tabs sometimes. Back then, one could rely on certain vendors for boards that fit. Those options don't seem to be available any more.

So one has to rely on luck (as many did then) or filing the edge down (as I plan to). Or buying a Chamonix board. (Which might well be the best solution for some, in the end.)

As many others, I’ve been buying lensboards from Luland for many years and the fit perfectly, all the time, on all my Chamonix. You can’t go wrong with them from a price/value standpoint either.

[Bernard Kelly]

That brings up something mentioned in the original thread. Tolerances may vary between cameras.

My Luland boards don't allow the tabs to fully descend (not even under force). This is why my lens fell off.

The tabs had a little bit of a grip and had always held on when the camera was even, but when I tipped it, the weight was too much. Those tabs have to come down all the way to be really secure.

[xkaes]

SOME cameras, like mine, have screws (mine has two) that hold the lensboard holder/tab in place. If yours is like mine, if you loosen the screws SLIGHTLY, you get a little more flexibility for the lensboard to fit. You obviously don't want to loosen the screws too much -- they might loosen all the way, and fall off!!!

[Bernard Kelly]

I did wonder about that, in the beginning. (The 45-N2 I have is as you describe.) I just didn't want to introduce a problem in the other, outward direction, as the screws can't be that long. Maybe a quarter turn ... ?

[Kiwi7475]

This seems surprising as the Luland boards are not particularly thick. I mean, actual linhof brand boards are a few tenths of a mm thicker than the Luland.

How far off are you in thickness between a Luland that doesn’t fit, and another lens board that fits without force? Do you have a caliper to measure both? That can also guide whether adjusting the screws has hope.

[Kiwi7475]

Another option if you don’t want to file and repaint, would be to ask Luland for a custom lensboard version that is sufficiently thinner. They do custom stuff like that. They might even cost the same or not much more since it’s a simple thickness adjustment.

If you know what thickness works and you don’t have a lot of lenses, getting new boards of the right thickness maybe be the easiest way — not as cheap as filing what you have, but less work. But you need to measure accurately what thickness works and tell them that.

[Bernard Kelly]

Another excellent suggestion. It never occurred to me that Luland might alter the thickness to suit. I've ordered calipers and will presumably have a better idea of how much my boards are off in a few days.

To answer your question, no, I don't have a board that fits perfectly. So I can't compare.

[Kiwi7475]

Well, then maybe take a sacrificial lensboard, file it down until it fits, snuggly but not too hard, measure the new thickness (right where the camera tabs are), subtract a slight bit of margin for fab tolerances (like 0.25mm or so), and talk to Luland. You could start with ordering one or two to make sure everything’s good and then buying the rest.

[Bernard Kelly]

Thanks, everyone, for your suggestions. I'll report back in a little while when I have calipers (and file) in hand.

[Bernice Loui]

Linhof Technika type lens boards have precision machined registration pads/bars on the rear and one registration bar front top. These are precise/accurate in their location and thickness regardless of the body thickness of the lens board. When the front standard mounting for Linhof Technika type lens boards are properly implemented, the lens board rest and is held in place at these registration points.

226706
Linhof Recessed lens board front registration bar.

226707
Linhof Recessed lens board back registration pads/bar.


Identical registration pads/bar on Luland/Linhof Technika type lens boards.
226708

226709

Location for these registration pads/bar are identical in location. Next set of images illustrates they are within a few 0.001" tolerance from no name generic to OEM Linhof.

What is most likely the cause of this problem has to do with the design of the lens board retainer on the Chamonix 45 N-2 instead of the Linhof Technika type lens boards as they are made/produced to surprisingly consistent tolerances and standards.

The properly solution appears to be, use the OEM lens boards specific to the Chamonix 45 N-2 instead of trying to fit Linhof Technika type lens boards to a camera not specifically designed for them.


Bernice

[Bernice Loui]

Comparison of Linhof, Luland, Toyo and genetic Technika style lens board front registration pad/bar thickness with a micrometer. Typical thickness is 0.090".

Linhof = 0.092"
226710

Luland = 0.090"
226711

Generic = 0.0925"
226712

Toyo = 0.090"
226713


Variation of 0.0025" is insignificant specially for a wood field camera.



Bernice

[Bernice Loui]

Comparison of Linhof, Luland, Toyo and genetic Technika style lens board back registration pad/bar thickness with a micrometer. Typical thickness is 0.086" likely due to board angulation due to micrometer clamping force needed to hold the board being measured in place for the Foot.

Linhof = 0.0885"
226718

Luland = 0.087"
226719

Genric for Technika = 0.084"
226720

Toyo = 0.084"
226721


They are quite consistent in their dimensions, problem here is likely due to the Chamonix 45 N-2 lens board mounting/retaining system not the Linhof style lens board's body thickness.


Bernice

[Kiwi7475]

Comparison of Linhof, Luland, Toyo and genetic Technika style lens board back registration pad/bar thickness with a micrometer. Typical thickness is 0.086" likely due to board angulation due to micrometer clamping force needed to hold the board being measured in place for the Foot.

Linhof = 0.0885"
226718

Luland = 0.087"
226719

Genric for Technika = 0.084"
226720

Toyo = 0.084"
226721


They are quite consistent in their dimensions, problem here is likely due to the Chamonix 45 N-2 lens board mounting/retaining system not the Linhof style lens board's body thickness.


Bernice

That’s exactly right — and it’s IMO disappointing that Chamonix’s response is just issuing a warning instead of taking responsibility and replacing the camera. It used Linhof type lensboards and they should fit.

However at the price of Chamonix boards, it’s far more economic to get skinnier boards than — by a factor of ~5.

[Bernice Loui]

Appears the solution to this problem is to use only Chamonix lens boards designed specifically for this camera, Done.

Another "penny wise, pound foolish" issue as the cost savings from using generic Linhof Technika style lens boards could result in floppy lens board/lens to camera causing long list of problems including the very real risk of having the lens fall off the camera... which will incur far greater cost than would be saved by using a non Chamonix lens board.

Lens board attachment and retention to the camera's front standard is basic, if any camera fails to have absolutely secure and positive lens board with lens retention, that camera should be a non-starter, non-owner based on this aspect of the camera alone. There is absolutely zero excuse to design in a iffy-marginal lens board/lens to front standard retention system, zero.


Bernice



That’s exactly right — and it’s IMO disappointing that Chamonix’s response is just issuing a warning instead of taking responsibility and replacing the camera. It used Linhof type lensboards and they should fit.

However at the price of Chamonix boards, it’s far more economic to get skinnier boards than — by a factor of ~5.

[Kiwi7475]

Appears the solution to this problem is to use only Chamonix lens boards designed specifically for this camera, Done.

Another "penny wise, pound foolish" issue as the cost savings from using generic Linhof Technika style lens boards could result in floppy lens board/lens to camera causing long list of problems including the very real risk of having the lens fall off the camera... which will incur far greater cost than would be saved by using a non Chamonix lens board.

Lens board attachment and retention to the camera's front standard is basic, if any camera fails to have absolutely secure and positive lens board with lens retention, that camera should be a non-starter, non-owner based on this aspect of the camera alone. There is absolutely zero excuse to design in a iffy-marginal lens board/lens to front standard retention system, zero.


Bernice

Of course — I’m merely pointing out that since each one costs $100, other options exist to those that cannot afford “the solution”. Everything in life is a compromise.

[Bernice Loui]

Carbon fiber Chamonix lens boards... Why _?_
No ponder why they cost what they do.

https://www.chamonixviewcamera.com/accessories/lensboards


Bernice



Of course — I’m merely pointing out that since each one costs $100, other options exist to those that cannot afford “the solution”. Everything in life is a compromise.

[Kiwi7475]

Carbon fiber Chamonix lens boards... Why _?_
No ponder why they cost what they do.

https://www.chamonixviewcamera.com/accessories/lensboards


Bernice

Carbon fiber is not as expensive as it used to be even 10 years ago, now, non-aerospace grade carbon fiber is $10/pound. But to your point, “why?” — I don’t know, it’s certainly unnecessary.

[LabRat]

I have been informed that CF is quite toxic in the manufacturing stage with it's ultra fine toxic dust that some poor soul will be exposed to making that lensboard etc... Not enough benefit for added cost/weight, someone's risk making it...

Plenty of other choices...

Steve K

[Alan Klein]

I have been informed that CF is quite toxic in the manufacturing stage with it's ultra fine toxic dust that some poor soul will be exposed to making that lensboard etc... Not enough benefit for added cost/weight, someone's risk making it...

Plenty of other choices...

Steve K

Workers in toxic environments wear masks with filters selected to prevent inhaling dangerous minerals and particles. Not only boards, how about tripods and thousands of other products that use carbon fiber? SHould we just stop production of products? Other materials require protection as well. How about chemicals for film manufacturing and development?

[Bernard Kelly]

Bernice is right. The optimal solution is a Chamonix board. This thread was never meant to be a criticism of Chamonix's service or products. Both are exemplary.

The other solutions, sub-optimal though they may be, have the usual appeal of DIY work-arounds, as evidenced by the amount of discussion here.

Many thanks to Bernice for providing those measurements and the explanation of tolerances.

[Alan Klein]

Bernice is right. The optimal solution is a Chamonix board. This thread was never meant to be a criticism of Chamonix's service or products. Both are exemplary.

The other solutions, sub-optimal though they may be, have the usual appeal of DIY work-arounds, as evidenced by the amount of discussion here.

Many thanks to Bernice for providing those measurements and the explanation of tolerances.

I bought a couple of Chamonix lens boards to go with my 45H-1 camera. They're made very well and have velvet on the inside for good light protection. And they're very light and of course are built to fit their cameras well. Likewise, their film holders are also made well

[Bernard Kelly]

That's true. I have one of their holders. It's a thing of beauty, as well as a delight to use.