DIY Camera Eyecup

[tom williams]

Greetings. I wonder if anyone has tried to fabricate a close fitting, flexible camera eyecup? The OEM rubber eyecup on my Bronica GS-1 AE finder is shallow and flat and doesn't adequately exclude bright ambient light that can wash out the dim AE LEDs. The faint AE LEDs are easily visible in typical indoor lighting, for instance.

I can visualize creating a form for casting the flat, rectangular eyecup base. But the broader, curving shroud seems more difficult to form and execute: it has to fit my facial geography and transition into the base.

Is this a job for a 3-D printer? Can rubber-like materials be 3-D printed? I have had a 3-D printer at the top of my want list for a couple of years now, but it keeps getting pushed out of first position by new control arms, pressure tanks, etc. So I am more focused on casting or otherwise forming raw material.

Any tips or ideas for materials, design and fabrication are welcomed.

cheers
Tom

 

[grahamp]

TPU is a flexible material that would probably do it. Not as firm as the usual rubber eye cups for viewfinders, but with the shape there would be some support.

Extruding from a square/rectangular base to an oval or similar shape is not too difficult. Presumably something asymmetric that would be steeper close to the nose, and shallower at the corner of the eye. The hardest bit would be working out the shape that works best with an individual. That's why manufacturers offerings are generic.

The camera mount would likely have to be a different material. Metal or a hard plastic like PETG.

TPU can be hard to print, and there are practical limits to how much overhang can be handled without printing supports. A wide, shallow eye cup could be beyond the capability of an FDM printer. TPU can only be cut, it won't sand, so removing supports is tedious at best.

If you do enough casting, a mold and a soft silicone material might be easier. You would still need to model the shape, of course.

I am sure there are other approaches.

 

[reddesert]

I've thought about making the shroud for an eyecup by cutting a piece from a mountain bike inner tube and sewing it together at the seam into a cone (imagine the way cones-of-shame for dogs are made by curving a flat piece). I don't know if it would be easy to bond this onto a ring for mounting to the eyepiece, either by rubber tension or by glue.

 

[BAC1967]

Tap Plastics can probably help you with what you need to make a mold and what material to make it out of. I've made silicone molds to make hard plastic parts, it's not that hard but may take some trial and error if it's not something you've done before.

Someone has been making these rubber eye cups for Bolex H cameras. It used to be that they were just sold on eBay by one person, now a lot of shops have picked them up.
Bolex EyeCup

 

[Sirius Glass]

Use a hard boiled egg as something to use as a mold or coat with multiple layers as a starter for the shape …

 

[Xylo]

You could actually design it in 3D using Freecad or something similar, cut the part out of a couple of cube shapes to make a mold. 3D print the mold in regular old PLA. Apply some release agent and pour-in some silicone with an accelerator (or just use Silicone 1 with some corn starch stirred-in, it makes it a bit less sturdy but works as an accelerator).

The best part of this is that you get to keep the mold so that you can produce as many eyecups as you want.

 

[tom williams]

I've thought about making the shroud for an eyecup by cutting a piece from a mountain bike inner tube and sewing it together at the seam into a cone (imagine the way cones-of-shame for dogs are made by curving a flat piece). I don't know if it would be easy to bond this onto a ring for mounting to the eyepiece, either by rubber tension or by glue.

Sounds like an excellent way to form a mold. Especially since I have inner tubes on hand....Thanks reddesert.

 

[tom williams]

Use a hard boiled egg as something to use as a mold or coat with multiple layers as a starter for the shape …

Interesting..... got me to thinking about using a silly putty to press into my eye socket, then painting a latex onto the silly putty. Combine that with the OEM base casting to make a single form for one of the TAP plastics compounds...

Thanks for the ideas everyone.