synchro compur

Hi all

 

I just received a schneider 150 lens mounted in a synchro comper. I

again learned something because the shutterspeeds are weird to me.

Rather then the 2,4, 8, 15, 30, 60 etc I'm used to, it's

1,2,5,10,50,100,200,400. Was this common to old shutters? My

lightmeter is based on the 'normal' shutter speeds so depending on

the shutter speed I choose it's useally 20-25% of or so (50-60, 100-

125, 200-250) as it is less that 1/3th stop it is not so bad I guess.

 

Reinier

Yes these speed ratings are normal to older shutters. Utilizing the equalvalent speed ie. 50 for 60 has never created a problem for me. Unless you have had a shutter calibrated you don't really know what you are actually shooting for speed anyway. As a practical test I once shot my 210 Apo Symmar against in Copal against a 8 1/4 Goerz Gold Dot in synchro compur. To the eye (the only rating I need for comparison because I make prints not charts) they were identical in exposure and contrast. I can't speak to shooting chromes but testing will answer any questions and allow you to adjust to a particular lens and its peculiarities.

Reinier, you are correct in both conclusions. It is an older system of exposure values and you can round it to the closest exposure time on your lightmeter without a big difference in the exposure itself.

If you do the math you'll see that the difference is actually only about a 1/4 stop or less in most cases, and as such will not be notable even with transparency films.

 

Cheers,

As suggested by an earlier poster, it is likely more important to know what the real exposure time is and its variability than it is what is marked on the shutter. The affordable Calumet shutter tester is a pretty handy tool to assess what your shutters are doing. Fred

The jump from 1/10th of a second to 1/25th, and the lack of the 1/15th speed, is a real problem with the old shutter series. Using 1/10th or 1/25th instead of 1/15th will result in about a 2/3rd stop error either way, always assuming the old shutter is reasonably accurate, of course.<br>You should avoid using an indicated 1/15th speed on your lightmeter, or make a -2/3rd stop adjustment when using the 1/10th, or a +2/3rd stop adjustment for the 1/25th of a second setting.

Correct me if I'm wrong, but I think these shutters are "continuously-variable" mechanisms. If you want 1/30, just put the shutter speed about halfway between 1/10 and 1/50 and you'll be set.

Mark; the synchro compur and compur shutters tah I have owned and used have no "half way" shutter speeds. Each shutter speed is set rotating cam ring; that has flats for each shutter speed . My old 1937 rolleiflex at 1/500 sec has an extra spring that is in parallel to the main shutter speed; when the camera is set to 1/500 second.

Mark, Copal shutters should not be set on the speed ring between click stops, otherwise the shutter will not work properly (Nikon advice).