Changing shutter for lens

[jonathan_lipkin]

I have two lenses - one is a Schneider 90mm f/8 Super Angulon, the other a 150mm f/5.6 Fujinon. In the process of testing the Schneider, I found that the 1s and .5s are off, so I'm going to send it out for CLA, but want to be able to use the lens in the meantime.

The Schneider is in a Linhoff Synchro Compur and the Fujinon is a Copal, not sure the diameter, but it is the same for both lenses - I was able to screw the front element from the Schneider into the Compur shutter. I didn't screw it in all the way in because I was worried that the rear part (element?) of the lens would hit the diaphragm. The Schneider is longer from the flange (the part that sits on the front of the shutter) to the end of the rear element by about .25in, I think. I haven't wanted to stick a ruler in for fear of damaging something.

Is this a bad idea? Can one just swap lenses into and out of shutters? I've seen threads on this board that suggest that one should not mount lenses into shutters, that this should be left to a repair tech.

[Jack Dahlgren]

I have two lenses - one is a Schneider 90mm f/8 Super Angulon, the other a 150mm f/5.6 Fujinon. In the process of testing the Schneider, I found that the 1s and .5s are off, so I'm going to send it out for CLA, but want to be able to use the lens in the meantime.

The Schneider is in a Linhoff Synchro Compur and the Fujinon is a Copal, not sure the diameter, but it is the same for both lenses - I was able to screw the front element from the Schneider into the Compur shutter. I didn't screw it in all the way in because I was worried that the rear part (element?) of the lens would hit the diaphragm. The Schneider is longer from the flange (the part that sits on the front of the shutter) to the end of the rear element by about .25in, I think. I haven't wanted to stick a ruler in for fear of damaging something.

Is this a bad idea? Can one just swap lenses into and out of shutters? I've seen threads on this board that suggest that one should not mount lenses into shutters, that this should be left to a repair tech.

A couple of things. The geometry of the two shutters may be different and this may cause an issue. If you can measure well enough you could ascertain if they are, but sounds like if you only have a ruler, you won't be able to measure that closely.

The second thing is that you will need a different aperture scale. Because f stops are proportional to focal length, different focal lengths will have different apertures on the same shutter and so the markings will be wrong.

If you can live with those things, then go ahead. If not, take it to someone who can deal with it.

Or buy another lens in shutter to use while yours is out for repair, and then sell it when it gets back.

Personally I don't care if the 1 second is off as long as I know how much off it is and that it is consistent. I would not even try to fix it.

[jonathan_lipkin]

Personally I don't care if the 1 second is off as long as I know how much off it is and that it is consistent. I would not even try to fix it.

That's a very good idea. It does seem consistently about 1.75s at 1s and .75 at the .5sec setting. I've read about recording the shutter with an audio recorder and using that as a poor man's shutter calibration. I'll give it a try, thanks.



The second thing is that you will need a different aperture scale. Because f stops are proportional to focal length, different focal lengths will have different apertures on the same shutter and so the markings will be wrong.
I don't know why I didn't think of that.

Thanks again.

[domaz]

Go get a cheap digital micrometer at Harbor Freight. You can use that to check spacing. I.e. measure how long between the front and rear lens elements in it's orignial shutter then check it in the new shutter. If the measurements match spacing should be correct. You can also use it to calibrate apertures for the new shutter. Measure the size of the aperture hole on each aperture setting on the old shutter then use those measurements to make a new scale on the new shutter.