3D printing LF lens boards

[abruzzi]

I have an LF camera that uses unusual lens boards, that are pretty hard to find. I measured and built a 3D model. I will need to run through a couple copies to make sure everything fits. But when I make some actual boards, I'm wondering what I'll need to do. I know less than nothing about 3D printing, and I'm not going to buy a 3D printer just to run off 3 or 4 lens boards. So if I send these off to a third party to print, what will I need to request? i.e. what material should I be using to ensure it is light tight? What infill is appropriate? are there other parameter I need to worry about?

 

[Dan Daniel]

I've done some work with this guy in Canada. And I know someone else who worked with him. Good results in both cases. Does his own 3-d printing. Contact him and see what he can do? He knows all the issues that concern a photographer. Heck, he might even know your lens board already.

Custom Camera Building

3d printed, custom made photo accessories. Film adapter, pinhole camera, 35mm, 120, 4x5, 5x7, 8x10, helicoid, bellows focusing cameras. Large format lens boards, adapters and standards for DIY camera building. Hasselblad cameras, accessories and service, panorama, medium format, 645, 6x6, 6x7...

customcamerabuilding.com

Miroslav Francruz info@customcamerabuilding.com

 

[abruzzi]

Thanks for the reccomendation. I looked at his site and he is doing lens boards, so he should have an idea how to make them light tight. My needed lens board is pretty rare--a Toho 100mm circular lens board.

 

[Dan Daniel]

If you already have a file you can probably send it to him. He might need to clean it up or such, but that's standard.

Both I and the other person used him for lens boards. He knows the issues. I needed a custom spacer to have a large shutter clear camera lens standard knobs, and he understood and it worked well.

 

[abruzzi]

My model is based on measuring an existing lens board, but I'll need to do some runs to make sure the light traps are the correct size. I modeled the lens board using OpenSCAD which was designed perfectly for me, since you just code the model using primitives and boolean interactions:

I haven't added the lens mount hole, but its in my code, when I get ready to do the final prints, I just uncomment a single line to give me Compur 00, 0, 1, 3. And adding custom sizes for odd mounts is easy, its just adding a single line of code with the diameter of the hole in the model definition.

 

[Nicholas Lindan]

My local libraries have "maker spaces" with 3-D printers available to the public.

 

[abruzzi]

My local libraries have "maker spaces" with 3-D printers available to the public.

I'm not aware of anything near me, though there may be. The local library has a seed library where you can check out seets to plan your garden, but no maker space. :-/

I sent my model off to a mail order place for $15 to do a test print. I selected PETG black at 100% infil. We'll see if it fits, but I don't know if PETG is light tight.

 

[Chuck1]

Can the toho use linhof boards?
I think the light trap dimensions are the same.
Yes it does look wierd

 

[abruzzi]

Can the toho use linhof boards?
I think the light trap dimensions are the same.
Yes it does look wierd

The only answer to that that I know for certain is my Toho can’t. Trusting a Google translation of the original docs for the FC-45A using a Linhof board requires an adapter board (which I don’t have.). I suspect the more well known FC-45X doesn’t need an adapter, but the FC-45A does. (I have tons of Technika boards form all sorts of manufacturers, so I tried a Linhof board, a Nikon board, a Wista board, a Shen Hao board, and a few no name boards, and they definitely don’t fit.)

 

[grahamp]

For filament deposition printers:
Lens boards are fairly easy to do if one face is flat, which is usually the case. They need to be done in a black material (PLA+, PET-G, or ABS probably) , and usually need at least 3 or more top and bottom layers (for the front and rear faces) at 0.2mm layer thickness. Provided you have enough front and back layers, infill is less important. The edges (sides) are structural and control for flexibility.

I usually paint the inside surfaces of my parts flat black. It cuts down on any reflections and adds extra density.

3D printing scores when doing odd-shaped boards or ones with complex light traps. Plain flat boards are better done in metal or plywood.

 

[abruzzi]

For filament deposition printers:
Lens boards are fairly easy to do if one face is flat, which is usually the case. They need to be done in a black material (PLA+, PET-G, or ABS probably) , and usually need at least 3 or more top and bottom layers (for the front and rear faces) at 0.2mm layer thickness. Provided you have enough front and back layers, infill is less important. The edges (sides) are structural and control for flexibility.

I usually paint the inside surfaces of my parts flat black. It cuts down on any reflections and adds extra density.

3D printing scores when doing odd-shaped boards or ones with complex light traps. Plain flat boards are better done in metal or plywood.

Thanks for some of the detail. I've come across some misc comments online like ABS shrings after printing, so needs to be scaled up slightly when printing, or PLA is brittle and sensitive to UV. I've also come across some comments that some materials aren't truly opaque, but without enough details to kow exactly which materials.

The overall thickness of the lens board is 3mm and on the outer lip and light trap groove the thickness is halved to 1.5mm. I specified 100% infill because it did cost any extra. The weight difference between 20% and 100% infill is going to be negligible I suspect, though given the the entire camera is about 2.4lbs, I am trying to outfit it with the lightest pieces I can (it already packs up suprisingly small).

 

[Richard Man]

I print 3-D lensboards all the time. I just use standard black PLA. I have no light blocking issues ever. Here's a custom board for front mounting a barrel lens on a Sinar Copal shutter. Some people would say that this is not a proper use of the Sinar shutter, but it works great for me.

 

[grahamp]

PLA is brittle - because it is one of, if not the, stiffest of the common filament materials. When it does break, it snaps. But the amount of stress required is non-trivial and will not happen in normal use. I paint internal surfaces of cameras/parts because, while black, the filament is glossy, and I see no reason to add extra reflective surfaces.

ABS can shrink (all materials tend to, to some degree), but there are ways to minimize this with heated beds, good adhesion, and slow cooling. Most filaments can shrink, but less than 1% on a 100mm board is bearable.

As for weight, PLA is less than half the density of aluminium, so a bit more of less infill will not make a lot of difference.

 

[abruzzi]

Thanks for everyone that commented. My boards work, I'm actively using them, and have had no issues. @Alan9940 has confirmed they fit a FC-45X, and I've confirmed they fit a FC-45A. If anyone would like to print their own, you can download the final STL files for Compur 00, Copal 0, Copal 1 and Copal 3 in the zip file attached to this post. (As Alan commented to me, there are not many Copal 3 lenses that the Toho could safely support, but the Rodenstock Geronar WA 90mm ƒ8 is in a funky Copal 1 with Copal 3 flange.)

I printed mine in black PETG with 100% infill.

If you'd like version of the STL with less common hole sizes for ilex, compound, supermatic, and all the lesser known shutters, let me know the size of the hole you need (diameter) in milimeters and I'll create a model. Just a note though, the 65mm copal hole is close the largest hole I'd be comfortable using on one of these lens boards, and the 65mm hole version looks like this so there isn't much room for a larger hole.

 

[Dan Daniel]

Looks great.

Can you give a brief idea of what was involved in sending files out for printing? Do STL files all work, or do they come in different 'flavors'? Did the printer require specific infill formats or such? I'm thinking of some of the issues when sending image files out for printing where they need to be formatted in specific ways, specific profiles, etc.

Of course what I hope to hear is 'upload file, make payment, wait, done.'

 

[abruzzi]

well, upload file, make payment, wait, done.

Really. STL seems to be the most commonly used file format for 3D printing, and most accept it, but the CAD program I used didn't use STL natively, but it did export STL. I used OpenSCAD because you build the model in a simple programming language that uses functions for primitives (everything in the model is a cylinder) and uses boolean relationships to great a union of shapes or a difference of shapes. This language could use named constants, so I built the model where I could define copal3 = 65 as well as all the other hole sizes, then one line states shutter_size = copal3. Change that line to shutter_size = copal0 and rerender, and I get a board with a differnt size hole.

There are a lot of places to print, but I used treatstock.com. The don't do the printing, but are basically a frontend for a lot of different printers. I uploaded my file, specified a quantity, a material (PETG in my case), a color (black, obviously), and a infill percentage (100%), and listed all the printers that could do what I want, and a price for each. I selected a printer, and completed the payment on Treatstock. They were printed pretty quickly and mailed to me. The printer was in Phoenix and I'm one state over in New Mexico, so they got here pretty quickly.

The first thing I sent was a rough draft of the board for two reasons--one to test fit, and two because I didn't know if my choices in material or design were appropriate. For very complex 3D models, I'm sure there can be issues due to how the object is built in layers. imagine a dagly thing (no not that) being printed. If its only connection to the rest of the object is above the object, it probably would have issues due to being printed in layers. Thats why I did a test print first before ordering a bunch. I had no experience and was willing to sink $15 to see if it would work for me.

Here is what I paid for 9 boards (4x #0, 3x #1, 2x #3)