Author Topic: The Contraption 25: Smena 8 to M39  (Read 1093 times)

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Francois

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The Contraption 25: Smena 8 to M39
« on: April 28, 2016, 10:47:05 PM »
OK, this one is really fantastic in the sense that it actually worked!
It all started years ago when the shutter on my Cosmic 35/Global 35/Smena 8 broke. I was a bit disappointed because I only had the chance to run a single roll through it... but it is Soviet era quality.

Now a few months ago I got the idea of mounting it on my Fed, so I ordered a flat black metal body cap from eBay. To my surprise, the one that I got was of really good quality and made from machined aluminum... not too bad for something that costs only a few bucks.

So I set out measuring stuff. I should have measured the donor camera more carefully before I took it apart. Live and learn as they say.
So anyways, I took out the focusing mount entirely. Lucky for me it was mounted on a flange that also held the shutter. I thought I'd mount the flange on the inside of the cap only to realize that I could not reach infinity as I was focusing beyond it! (to infinity and beyond sadly doesn't work on cameras), so I tried putting it on the outside only to now realize that it could only close focus. So I decided to use the dremel on a stand to machine the front of the cap until I could reach infinity. When I got close enough, I used epoxy to glue the flange in place. Some JB weld to block the light leaks and some craft foam were used to shim the front bezel into place. I'll replace the foam with a nice varnished and stained piece of wood when I get some of the right thickness.

I also collimated the lens, what's the point in having an out of focus lens?
To do this, I used the old shoot-through the lens trick. It works surprisingly well, especially with a long telephoto. Someday, I might even build myself a special collimating box.

Now some pointers for doing similar jobs.
-Measure the donor camera's flange to film distance before attempting to repair it.
-The Leica thread mount flange to film distance is 28.8mm
-Make sure you mark the top of the focusing mount before removing it, it will come in handy later.
-Noticing where the lens reaches infinity is very handy to get things in the right ball park.
-Measure not twice but three times!
-Make sure you work on this when not too tired or preoccupied by other things, you will make mistakes!
-Always measure before you glue, especially with epoxy.

So now, I have a brand new 40mm f/4 Lomo T-43 lens for my camera. Just to give an idea, at f/8 it's focus from 6½ feet to infinity. Perfect for rapid street photography.
« Last Edit: April 28, 2016, 10:49:29 PM by Francois »
Francois

Film is the vinyl record of photography.

clagom

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Re: The Contraption 25: Smena 8 to M39
« Reply #1 on: April 29, 2016, 11:14:01 AM »
Pretty cool! And useful guidelines to follow :) Thanks
Will you post more photos? Curious to see the whole process...

Francois

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Re: The Contraption 25: Smena 8 to M39
« Reply #2 on: April 29, 2016, 02:08:52 PM »
Sorry, I didn't take any pictures of the process.
I don't think any of it was really that impressive.
But I might give various tricks that I use, like the dremel on the base for even cuts.
Francois

Film is the vinyl record of photography.