Feature Limited Compur Shutters
In my collection of useless stuff that I've acquired because I didn't know better, I have two Compur 0 shutters that have fairly limited diaphragms. That is to say, at wide open, which says f/5.6, the diaphrams are substantially stopped down. One of them has no focusing lever.
What's the background on these lenses? I have to wonder whether they were originally intended for large format use, or if they have been repurposed from somewhere else - maybe some kind of a rangefinder?
Re: Feature Limited Compur Shutters
Polaroid Copal shutters are like this too. They were designed for a specific mass production camera which didn't need a wider diaphragm or a focusing level, so they probably used a limited shutter to keep costs down.
Re: Feature Limited Compur Shutters
Some shutters have a small screw that limits the aperture. Remove the screw and it opens up fully.
Kumar
Re: Feature Limited Compur Shutters
I've had shutters that the curved open "hole" that the aperture pin traveled along in limited the widest and smallest apertures. On one of these shutters. I increased the size of the curved "hole" and intern increased the widest aperture and decreased the smallest aperture. Did it very carefully with a Dremel bit and a small vacuum hose picking up the metal shavings. Shutter was clamped in an X-Y table vice under a small hobby drill press. Trick was to go really, really slowly wearing a pair of close up glasses. Took me a few tries on plain pieces of sheet metal to get the hang of it.
Re: Feature Limited Compur Shutters
Quote:
Originally Posted by
B.S.Kumar
Some shutters have a small screw that limits the aperture. Remove the screw and it opens up fully.
Kumar
Yeah, on one there was a pin on the ring that looked like it could be pressed out or ground off. I haven't really fiddled with it yet.
Quote:
Originally Posted by
Greg
I've had shutters that the curved open "hole" that the aperture pin traveled along in limited the widest and smallest apertures. On one of these shutters. I increased the size of the curved "hole" and intern increased the widest aperture and decreased the smallest aperture. Did it very carefully with a Dremel bit and a small vacuum hose picking up the metal shavings. Shutter was clamped in an X-Y table vice under a small hobby drill press. Trick was to go really, really slowly wearing a pair of close up glasses. Took me a few tries on plain pieces of sheet metal to get the hang of it.
I forget how the range was set on the one I opened up. I think I recall just being able to remove the existing pin, and putting another in a different hole, but that something else stopped the lower range. You could see that they had a couple of different setups that could be built around the same parts.
Re: Feature Limited Compur Shutters
Some Compurs had limited aperture ranges to match the lenses installed in them. I have a Synchro-Compur where the aperture only opens as wide as the pupil size of its 65/5.6 Super Angulon.
Re: Feature Limited Compur Shutters
Quote:
Originally Posted by
B.S.Kumar
Some shutters have a small screw that limits the aperture. Remove the screw and it opens up fully.
Kumar
Much prefer to just increase the range that the pin can travel/move in, verses removing the pin altogether. Years ago removed the pin, and it allowed the iris to open up more. Unfortunately one time I closed down the iris and accidentally applied too much pressure, forgetting that the pin's movement was not limited anymore... The leafs in the iris never opened up evenly again.