Homemade lens board ?

[Gerry Harrison]

Hello LF users,

I am just new to LF and this forum. Have just purchased a Cambo SC-2 on Ebay and a Caltar S-II 210 5.6f lens with Copal #1 shutter. The Cambo came with no lensboard and here lies the meat of my question..as a home woodworker it should be easy to make a lensboard of something like quality birch aircraft ply and a good Forstner bit for the hole..a 1 5/8" bit would come very close with a bit of sanding to fit. Could someone please tell me the thickness of a Cambo lensboard ? Any suggestions or ideas in this area from those who have attempted this would be great..for example do I need a seal around the outside of the board etc. This is my second time to post this question and my first time on the forum..I don't know were the other one went so forgive me if it is out there somewhere. Is there anyone in the on this forum living on Vancouver Island B.C., Canada ?
Thanks Gerry

[Nick_3536]

Don't know about the Cambo but in general boards are fairly forgiving. If the hole isn't overly large the lens will fit fine. Various materials work.

[Terence McDonagh]

Do a search on this site. There have been many many discussions on this.

Personally, I use a piece of tempered hardboard (masonite) from a cheap clipboard, and two layers of black mat board on the back to provide the light baffle. I make the hole by drilling a series of overlapping holes at the circumference. With many of my old lenses I don't have a proper flange, so I just screw the lens into a tight-fitting hole. Except for large, heavy lenses this works fine.

[Ralph Barker]

Masonite!? Shouldn't a "proper" LF lens board be made of laminated Brazilian Rosewood? ;)

As others have noted, lensboards are pretty forgiving. I've laminated various hardwoods, and past threads have suggested materials like Pergo wood floor covering. Just measure the opening dimensions, and allow for a light trap rabbet around the edges. Ideally, paint the backside of the board flat black. The light trap rabbet can be done with your router, or by laminating (cross-grain for added warp resistance). Also, allow about 1/4"-3/8" of thinner material around the lens hole for the retainer ring if you laminate or route the edges. That will become obvious when you try to mount the lens to a thick board.

For Forstner-oriented lens hole sizes, see:

http://www.largeformatphotography.info/lensboard_hole_sizes.html

[Gerry Harrison]

Ralph and others thanks for your time & input...you have given me plenty of ammo to start my project once the lens arrives and measurements are made to confirm my calculations. For those of you who have Cambos..you may find this interesting although I'm sure it is common knowledge to some..my Cambo SC-2 is the Euro name given for the Cambo NX here.what no fireworks. lol Where on this forum could I locate Canadian LF users especially those situated in British Columbia and fine tuning more Vancouver Island.

Thanks again Gerry

[Paul Fitzgerald]

Hi Gerry,

"Personally, I use a piece of tempered hardboard (masonite) from a cheap clipboard, and two layers of black mat board on the back to provide the light baffle."

Black foam-core works well too and is really easy to trim. The masonite is just the right thickness to work with the retaining ring. If you want, a cork gasket between the shutter and board will stop it from turning without over tightening the retainer.

Have fun with it.

[Ralph Barker]

. . . Where on this forum could I locate Canadian LF users especially those situated in British Columbia and fine tuning more Vancouver Island.

Click on the "Members List" item in the navigation bar, and then "Advanced Search". That will allow searching on location. Not everyone includes their location in their profile, however.

[Tracy Storer]

Cambo boards are cast aluminum, 1/8" thick at the edges, but have fairly deep grooves in the back to mate up with ridges on the cameras front...you might have fun making one out of plywood, but then again. Buying a used one will be a lot easier. There have got to be tons of used boards out there, even I have some.

[Don Wilkes]

Gerry: I'm in Victoria, too. If you want to chat, drop me a note at don.wilkes [at] gov.bc.ca

Cheers,
\donw

P.S. Did you know of the workshop coming up in Vancouver? We could meet a whole bunch of other local LF folk there, I think!

[Alan Davenport]

Gerry,
Easy lensboard to build. You'll need a router or a drill press to do a neat job of the slot on the back side of the board. I do mine with a Dremel cutter in a drill press; takes longer than a router but the result is the same.

Here's a drawing of what I've been building:

http://home.comcast.net/~w7apd/public/lensboard.png

The groove on the back is the light trap, so no further seal is required. I've used my homemade boards with everything from pinholes to a 10" f/4.5 lens in a No. 4 shutter, so I can say they are both light-tight and sturdy enough.

[Gerry Harrison]

Alan,

I am so greatful you posted this excellent drawing.....I have been at work measuring the face of my Cambo and considering all the avenues I can take to construct the lensboard. Your diagram has saved me a whole lot of time and reaffirmed my decision on the best route for construction. Its very interesting you and others have mentioned aircraft grade plywood..this was my conclusion also as I build scale sailplanes and have this stock on hand. Have just recently purchased the a forstner bit close to #1 size hole as this will give me a nice clean hole if done properly. Just curious on the bit you use in your dremel for the light trap..obviously it would have a flat bottom and the width of the grove..is there a model number for this as I have a dremel tool and a drill press. Just waiting for my lens to show up before I start cutting wood to take some last minute measurements so there are no surprises. I hope you all understand this is my first LF camera and I may appear a bit ignorant at this stage..thanks again for all how have come to my aide. And also a big the to Don Wilkes..for his kind help to all my questions.

Gerry

[Gerry Harrison]

Alan,

I am so greatful you posted this excellent drawing.....I have been at work measuring the face of my Cambo and considering all the avenues I can take to constuct it. Your diagram has saved me a whole lot of time and reaffirmed my decision on the best route for construction. Its very interesting you and others have mentioned aircraft grade plywood..this was my conclusion also as I build scale sailplanes and have this stock on hand. Have just recently purchased the a forstner bit close to #1 size hole as this will give me a nice clean whole in done properly.I have a Dremel tool and drill press..curious on the bit you use for the router work on the light trap..it obviously will have a flat bottom and the width of the groove...I sure it must be fluted with a flat bottom. I am just waiting till my lens arrives and I can do some last minute measurements so there are no surprises.I hope you all realise this is my first LF camera and I may appear ignorant to some..but I appreciate everyones contributions to my post. I would also like to thank Don Wilkes who has been very patient, keen and enthusiastic with all my questons.

Gerry

[Gerry Harrison]

All,

As you can see I am new to the forum also, so my apologies for the double post didn't realise we had a page 2.

Gerry ( LF in training )

[Alan Davenport]

..curious on the bit you use for the router work on the light trap..it obviously will have a flat bottom and the width of the groove...I sure it must be fluted with a flat bottom.
Gerry,
I do use a Dremel bit, one of the cylindrical cutters with teeth on the side and bottom. I mount the bit in a drill press. Then I set a fence on the drill table that places the groove the correct distance from the edge of the board. Using a piece of scrap, I set the stop on the drill press for the depth of the cut. Then I cut the groove with repeated, overlapping strokes of the bit. If I were making a lot of boards I would build a dedicated fixture to do this with a router, but for a one-off job every couple of years the drill press works fine.

[Andrew O'Neill]

Andrew here in Coquitlam, BC. Lots of us from BC on this forum. I lived in Victoria in the 80's (gradded at UVic)...I miss Victoria!! I have an old 4x5 cambo that I haven't used since '98. That's the camera that I started on.

[Gerry Harrison]

Hello Andrew,

Nice to meet another LFer from my neck of the woods..looks like we share the same camera but at different stages of our hobby. My daughter lives In Port Coquitlam so maybe one day we can meet for coffee...thanks for saying hi its a pleasure.

Gerry

[Dave Moeller]

I've made lens boards for my Cambo using hobby plywood. I cut a board to the outside dimensoins that Alan provided, and then cut a smaller square that would fit just inside of the area that Alan routes out. I glue the two together and drill the hole for the lens, and after a test fit I paint the whole thing flat black.

I haven't had any light leak problems using these boards. The router's certainly the more elegant solution, but not having access to one I came up with the two-level design for myself and it's worked fine.

Best of luck.
Dave