
Posted: Wed May 14, 2003 2:37 am
There are about three ways to hold glass inside the front cell.
1. insert them all from the back, thread on a retaining ring. (oldest method)
2. Insert the rear element from the rear, the front element from the front and use the part that says "optar" as a retaining ring.
3. install all from the rear and lock the elements by spinning the rear of the case against the glass. A permanent seal.
Yours is in the middle. Getting the rearl element out will be easy, just be carefull not to get the glass cockeyed as you remove it.
The front element will be more difficult. you'll need to buy a rubber stopper with one end slightly smaller than the max diameter of the retaining ring. Black rubber can work, but the white rubber is better. These can be had at
http://www.microtools.com
Then carve a dish in the center of the stopper so it doesn't touch the glass. Then press and turn and hope it works. Worst case senario is you have to drill two small holes in the ring and use a spanner wrench.
Now that I've answered your question, why do you want a shutter with a pin hole camera? Are you doing pinhole or zone plate? At f386 the exposures are in the seconds, if not the minutes. Most Graphex shutters are accurate to within a 1/2 stop unless they've been adjusted recently, then you can rely on about 1/3 of a stop.
Now if you've been shooting with a Graphex (Rapax) shutter and been happy with the results, you don't need to be hyper accurate with your pin hole exposures.
A finger and a stop watch should be able to time an exposure of ten seconds to within a half second. That's 1/20th of a stop! Now if you'd like a cable release, then you might want to invest in a repro lensboard ($20) and then experiment with a hinged or pivoting sheetmetal in front of the pinhole. Remember the shutter doesn't have to be right against the lensboard. Pinholes don't allow a whole lotta light when pionted at a well lit scene.
You won't get any fog from a pinhole look at a flat black piece of sheet aluminum when its 1/8" away from the lens board for the 30 seconds it takes you to pull the darkslide and open the lens, even at the beach.
I say find some black matte board, cut it to fit the front ot the camera (yes I know it won't fit in the light trap like a metal board, if that scares you tape the edges) Now cut a 1/2" hole in the middle and tape your brass to the matte board. It'll be a lot faster and cheaper, and safer, should you like to return to optical imaging.