SilverStax

[laptoprob]

Instead of hijacking another thread I'll tell the story here.
I've been away from RFF for years now, since using m43 camera's instead of Leica's and Bessa's.
Using mostly Fuji X nowadays and sometimes printing on Instax Square. I started thinking about using a camera to expose Instax film directly.
Since the Square format is only slightly smaller than 6x6, I got a few classic folder camera's. Agfa Anaco Speeder, Ikonta M and an Agiflex. The space occupied by the bellows makes the resulting format about 2mm smaller on all sides than Instax Square. And it's hard to get the Instax film on the projection plane in the camera: there's too much camera in the way.
Looking at a Yashica 124, that problem may be even bigger. What a gem of a camera though... Explaining to the seller of the Yashica, he showed the Silverflex. I had never seen a camera like that. Without the film holder, only an empty box remains. A twin lens box!

 

[laptoprob]

This is the Silverflex, a close copy of the Ricohflex.

 

[laptoprob]

The mirror is 70 years old and the focus is stuck, of course. Getting the focus of both lenses working is easy. I like the simplicity of this design!

 

[laptoprob]

Now the Instax part. Jollylook makes an all manual wooden or cardboard pinhole camera. The manual wrench Instax part is sold separately, in Mini and Square format.
The cartridge is 1,5mm thick and the development part has a thickness of about 2mm, surrounded by a flange to keep it all flat.
The film plane in the camera is about 1mm in front of the back of the 'box'. So about 4,5mm of the back of the camera box must go, to get the Instax cartridge on the focusing plane.
Plan B would be to recess the two lenses by a similar distance, but that would be too complicated.
Abit of the development unit must go to make space for the TLR top-viewing system. This is all the real necessary hacking.

 

[laptoprob]

So where do I stand now? Focus checking!
And some extra tinkering to get the focus plane correctly set. Then: how can I get this light proof? Wrapping the whole thing is very complicated. But I don't need all that.
The development unit has flanges just outside the projection (almost) square. And the image square is again a bit smaller. Enough to make a black leather shroud and glue it to the unit's flanges. The shroud extends all the way to the front of the camera, we'll besides the lens opening ofcourse.

 

[laptoprob]

This is -almost- the projection plane. You can see the sides of the leather shroud. This is the plane where the Instax cartridge is put.
Next: leather wrapping around the development unit. This shouldn't need to be light proof, but I have my doubts about the ejection system in the development unit. That might well create a light leak.

 

[laptoprob]

A smaller problem is the ISO800 sensitivity of the Instax film. Instax cameras use rubbish plastic lenses and a minute aperture to somewhat correct the 'lens' flaws.
Even though the Silverflex goed beyond 1/100 (1/200, Jay!), I need ND filters. With one ND8 I can get to ISO100. That would restrict me to Sunny Sixteen in today's beautiful weather. Another ND8 can get me to F3,5, wide open.
So I glued a 37mm filter retaining ring to the front of the taking lens, sanded the rear of that filter ring down to a female-female lens ring and mounted the two ND filters and a lens good.
The first one is wide open. Sole light leaks on the right side, that's the photo ejection-system side. The second is at f8. Parallax seems adequately corrected, this is about what I saw on the focusing glass. A bit less light leak, but strange blooming. That must be something in the film.

 

[laptoprob]

Oh... The horizontal line in the f3,5 photo is ejection error. Do not stop wrenching. Fold the focus loupe up, so it doesn't collide with the photo!

 

[laptoprob]

Conclusion after first pack: I need pressure springs to press the photos to the focus plane. Lack of these may well cause the light leak as well. Too bad the Jollylook set doesn't include these.

 

[pyeh]

Fantastic work. Thanks for showing us.

 

[laptoprob]

Doing more online research I found out that the two foam strips in the development unit pack replace the pressure springs I was missing. So now I don't have to scavange another Instax camera for them and complete the SilverStax build.