homebuilding a lensboard

[fabio pollero]

Hi everybody,

there's anybody who succesfully built a plane lensboard such as mine calumet met al one? I was thinking to use a soft mould to 'print' the back of the original l ensboard and try laminating with epoxy resin in thin layers using the vacuum bag ging system. When the resin packs you just have to cut the board at his proper s ize and drill the hole at required 'copal' size.

Any (disgusting as well) comment??

Thanks and ciao Fabio Pollero Savona/Italy

[Ed Balko]

I've made several lensboards for my Calumet CC-400 camera from 1/8" aluminum tooling plate.

This isn't a difficult material to work - a hacksaw and files or carbide woodworking tools are suitable. I sand both sides of the board with 80 grit sandpaper and paint the inside with flat black spray paint. If you use a power sander with this relatively coarse sandpaper, an attractive matte finish is obtained on the unpainted aluminum.

[Conrad Hoffman]

I need to make one right now, and will probably use scrap aluminum plate from an electronic "rack panel". I've made them in the past by gluing together two pieces of fiberboard, one slightly smaller to fit the internal cutout and prevent light leaks. The epoxy method would probably work, but seems like a lot of work. You could certainly make a mold from 2-part RTV and cast a new lensboard with epoxy. Be careful about the filler, as many dye type fillers transmit UV and/or IR! Painting it will work, but chips in the paint might leak light. Actually, that method might be quite good, but I don't have an original lensboard to copy.

[David E. Rose]

The lens boards for the Bender 4x5 kit ( my first view camera) are made of black plexiglass. When I needed additional boards, I got a sheet of black plex and cut my own. You can cut the stuff with woodworking tools, the lens hole can be drilled with a cheap "butterfly" wood bit. When the fabrication was complete, I sanded the board with fine grit paper to make it a flat finish. I don't see any reason this material could not be used for other types of lens boards.

[neil poulsen]

I've had good luck with 1/8th inch hobby board, a plywood that you can pick up at most hobby stores. At least, this works well for Deardorff boards and such like.

[Enrique Vila]

The lensboards i use on my linhof tech V were made by myself using a material called MDF. It is sintetic wood, and should be available at any home improvement store. Once I had the model, I cut it and used a dremel for slots and finish.

[Padu Merloti]

I just bought a 180mm-355mm convertible symmar and I'm planning on making the lensboard myself while I wait for the lens to arrive.
My question is how critical the thickness of the material is for this type of lens? I would assume very critical, since the front and back lenses work together to achieve proper focus. Does anybody know what is the exact thickness of a lensboard for this lens? Also, I know that the shutter is a compur, but not the exact size. How can I know what shutter goes with that lens? I will know it in a couple of days, but I can't help my anxiousness.

At last, is the hole drilled dead center in the 4x4 board?

[Gene McCluney]

I just bought a 180mm-355mm convertible symmar and I'm planning on making the lensboard myself while I wait for the lens to arrive.
My question is how critical the thickness of the material is for this type of lens? I would assume very critical, since the front and back lenses work together to achieve proper focus. Does anybody know what is the exact thickness of a lensboard for this lens? Also, I know that the shutter is a compur, but not the exact size. How can I know what shutter goes with that lens? I will know it in a couple of days, but I can't help my anxiousness.

At last, is the hole drilled dead center in the 4x4 board?

The mounting hole for the lens will have to be thin enough to allow the shutter to be attached by the retaining ring. The rear lens element screws into the shutter, so if the hole is big enough for the shutter to mount, the lens elements will be fine. If you are using a thick board for the lensboard, you may have to use your router and route out a channel around the lens hole, to get the material thin enough to get the retaining ring on the back of the shutter threads. Some older lenses mount with a mounting ring that attaches to the front of the lensboard with a flange that accepts screws. In this case, you just need to make sure your lensboard hole in the middle is as big as the rear element on the lens, so you won't restrict the light.

[Ole Tjugen]

The Schneider Symmar 180mm f:5.6 / 315mm f:12 convertible is in a #1 shutter.

The lensboard should be thick enough to allow the retaining ring to get a good grip on the board, which is a very wide range. The rear cell of the 180/315 had a diameter of 45mm, so you will need to unscrew that cell to mount the lens on a lens board.

[scott_6029]

A second for Birchwood hobby board that works very well -

[John Schneider]

I've had very good luck in machining Technika boards from 6061 aluminum sheet. I've made boards with odd shutter sizes, thicknesses, etc. to fit old or oddball lenses. If anyone decides to go this route, do yourself a favor and buy a boring head off eBay to bore the holes.

Going the epoxy/fiberglass route, especially vacuum-bagged, is way too much work and mess. If you have the inclination and tools, make the lensboard from aluminum. Otherwise, made it from plywood, MDF, basswood, or something similar as suggested in the other replies.

[Brian Schall]

I've use the bottom of an old kitchen draw to make lens boards. It's a composite board that's hard, doesn't flex and is easy to work with. Spray paint it flat black inside and out and I'm good to go.

[Kevin Klazek]

I agree with John, your fabrication sounds way too complicated. I have made several lens boards for my Dorff from 1/8 in baltic plywood and mahogany veneer availible from hobby or craft shops. All you need is a saw, some sandpaper and glue. For precision holes a small drill press with an adjustible hole saw works great but you could just use a jig saw. I cut the actual lens board, then cut a second smaller board that is glued to the back to act as a light trap. I then finish it with flat black paint on the inside and varnish on the mahogany veneer on the face side.
Pretty simple fabricaton overall.

[fred arnold]

A related question: has anyone made a recessed lensboard for a B&J 5x7 wooden tailboard? Lots of room to maneuver (relatively), but out of production long enough that I'm not sure there ever was one.

[Ernest Purdum]

Since Fabio Pollero is in Italy, my suggestion may not be as useful as it would be to someone in the United States. In addition to the hobby shops birch plywood, which is available in several thicknesses, you can obtain hardwood of several varieties in a range of thicknesses from www.micromark.com. Laminated together with the plywood, you can obtain any thickness you need. Boards made this way are very strong.

[Alan Davenport]

I'll cast another vote for the birch hobby plywood. I've made a number of boards for my Calumet monorail (late model; same boards as Cambo) from 1/8" ply with nary a problem nor a light leak, including when used with pinholes at f/400. The latest effort was an adapter to mount Technika boards on the monorail, again no problem.

It's easy to forget that large format cameras are inherently low-tech devices. Other than the lens, and the shutter (if desired,) there isn't much about LF that you can't cobble together with basic tools and a little patience.

[eddie]

i have no wood working skills or tools. i use a foam care backing cut a hole in it an screw the lens in (i usually have no mounting flange cause most of my barrel lenses do not come with one) and then tape it so it does not fall out. a bit ugly but it works in a pinch.

eddie

[Jim Rhoades]

Here's another vote for Birch plywood. Like Kevin I pimp mine up with Mahogany veneer. If it's a long winter with lot's of snow I even go for Birds eye Maple center with bookmatched Zebrawood edges. Quarter sawn Oak, Tiger stripe Oak etc.

What works neat is the iron on veneer edging make for cabinet work. You can make all kinds of designs with mix and match woods.

BTW, a Rotatrim is the best veneer cutter ever made.

[steve_geo]

My question is how critical the thickness of the material is for this type of lens? I would assume very critical, since the front and back lenses work together to achieve proper focus. Does anybody know what is the exact thickness of a lensboard for this lens? Also, I know that the shutter is a compur, but not the exact size.

Sorry, .. don't know the lens your talking about.

Sk Grimes has a table of lens board thicknesses for copal shutters
http://www.skgrimes.com/lensmount/shutmt/index.htm

I believe with copal shutters, the shutter itself provides the spacing for the front/back lens seperation independant of the lens board thickness.

SK Grimes also has a table of lenses/shutters, .. don't know if it's any help.
http://www.skgrimes.com/fits/index.htm

[watsekalimoman]

After reading the info off of a post here in the archives, and realizing I have the ability to 1-draw straight lines with a pencil and ruler 2- cut on said lines, 3- draw a circle, and 4-cut a hole the same size as the circle... I did just this the other day!

I stopped at a hobby shop and purchased 2 small sheets of Birch Plywood, manufactured by Midwest (that is what the label says). It is marked for Aircraft use. Each sheet is 6" x 12" one is 3.0 mm and the other is 2.5mm. The thinner was $3.79 and the thicker $4.09 (Chicago). I also purchased a 3 in one wood saw (keyhole and two flat miter type saws) for $7.30. The saw is made by Zonal Tool. They have a web site, but I am unsure if I can post it here. So for less than $20.00 I had everything I needed to make 4- 4x4 lensboards for my Calumet 4x5.

After getting home and making the measurements and the simple cutting with the saw kit I purchased, the board was to perfect dimentions. After marking dead center, drawing the hole for my Copal #1, I took out my Dremel and drum sanded out the perfect circle. Lens was mounted after about 15 minutes of work and another 15 min of dusting and cleaning. I will paint it this weekend. I have used it and it works great!

Again one of the many things learned here... But- Bonus!

I just received my Beseler CB7, and in the process of setting it up, realized the lensboards are identical in size to my Calumet 4x5! I took the new lensboard with my lens, and it mounted right up, and focused up! I thought it was here that I read that it is best to use the lens that you took the photo with to enlarge it... It works- but I am a newbie. Just lucky?

Anyway- thanks again for being a great reference for newbies like myself. I hope to start sharing some of my images soon. After more than 30 years in 35mm I have a new passion for photography. It is no longer just to get a photo (press work...) but to work to truly capture an image. I truly have a new found love in large format. I have not touched my 35mm gear since. Its all your fault...And ebay's...

Thanks again!
Scott Anderson

[Ernest Purdum]

Taking lenses in general are intended for different ratios between subject and image than are enlarging lenses. The exceptions are "process" lenses which have smaller apertures than enlarging lenses.

There are also some possibilities of heat damage. There are lots of very good enlarging lenses available at rather moderate prices.

[Jim Jones]

I thought it was here that I read that it is best to use the lens that you took the photo with to enlarge it... It works- but I am a newbie. Just lucky?
Scott Anderson

Ernest is right. Camera lenses may work well enough on an enlarger; a few of them certainly do. Most don't do a LF negative justice. A lens designed for enlarging is likely cheaper than one intended for camera use. If you get a good enlarging lens, it can be used on your camera for macro photography. The lack of a shutter is no big problem for indoors work, and sometimes not much of a problem outdoors.

[watsekalimoman]

I have only enlarged 3 images with the CB7, and am still making sure it is aligned. But since I am such a newbie to LF, I only have 20 or so to choose from. All of the pics have been taken with my 135mm Wollensak in a Rapax shutter, the lens I got with the camera.

The lens that came with my CB7 is a 50mm. I was told it was being shipped with a 135mm and a 150mm, but they missed the box. I wanted to use it as soon as I got it, and that is where I read up here on enlarging lenses. When I realized that the lensboards were interchangable I gave it a try. All three of the images, a snowy landscape, a class photo, and a cityscape, came out great... to me. 4x5 to 11x14- A few areas out of focus towards the edges, otherwise sharp, and good contrast. But these were just fast prints, not fine prints.

After reading your responses I have a few questions.

1- Am I just lucky, or do I have the type of lens that works for both?
2- Would I be able to do this with my 210mm Schneider convertible? But why?
3- When you mention heat damage, is that from the lightsource focusing on the lens or the heat from the lightsource being close to the lens?

Thanks again, and I hope I can make my scanner work so I can show a few.

Scott

[Ernest Purdum]

Scott, 1. Most lenses will work. The question is, how well? The important point is that you are happy with the results. Perhaps you will want to continue using your present lens while waiting for an enlarging lens to show up.

2. Yes, a convertible Symmar would work, probably better than most taking lenses.

3. The heat damage possibility is associated with condenser enlargers and the focused lamp is the major heat source.

By the way, congratulations on your lensboard success. I think you may be encouraging others.

[Padu Merloti]

Ok, I finished building my lensboard this morning. Here's what I did:

Materials

Aluminum sheet (1/16")
Jigsaw
Square
Sand Paper
Black spray paint
Drill press & C-Clamps
Hole saw
3M spray glue
Hot silicon glue
Faucet o-rings
Foam sheet (outlet insulation from home depot)


1. Cutting the aluminum sheet wasn't a problem. The only issue I had is that because I've decided not to use a guide, the cuts weren't 100% straight. I had to use sand paper (laid flat on the bench) to get the cut straight.

2. After I had a 4x4" aluminum sheet, I've sanded one surface with 200 grit sand paper, then 100 and then steel wool.

3. Painted one surface black, let it dry and then used the steel wool to remove the gloss from the paint.

4. Using the hole saw, cut the hole in the middle of the sheet for the lens. That's where I had most of my problems. One because the hole saw vibrates off-center a little bit, and second because I had the drill press 0.5 degree off perpendicular. The hole saw on aluminum is definitely not a precision cut. It was way larger than the lens diameter. When I tested the lens on the hole, the lens nut covered the whole diameter, but there was considerable play.

5. In order to create a bit more pressure and have a snug fit, I've made a washer out of foam that people normally use for outlet insulation ($2 at home depot) to go between the lens nut and the lensboard.

6. Another problem I had was the thickness of the board. 1/16" is not thick enough to fit snugly on the camera. Light was leaking around the board, even though the board was cut very tight. What I ended up doing was to buy some faucet o-rings (remember: perimeter = 2 * pi * radius :) ) which thickness would fit exactly into the groves around the lensboard place in the camera. I've cut the o-rings to make them linear and then glued around the lensboard (careful measurement first, of course) with the 3M spray glue (don't forget to mask the areas where you don't want glue). I've reinforced the o-rings using hot silicon glue, and after dry I've removed the excess.


Result: perfect fit, no light leaks, lens solidly mounted on lensboard. (I'll take a picture later).


Now, I'll start having fun... :D