View Full Version : Compur Electronic ?

Calamity Jane
15-Jul-2005, 06:27
Any good?

Any problems with them?

Somehow a battery operated shutter goes against the grain. OTOH, working in the industry, electronic should be very accurate and stable.

I ask because the Wollensak pneumatic on my new/old 8x10 isn't in very good shape. It's consistent but only runs 1/20th and slower, even after cleaning.

Thanks for comments

Ernest Purdum
15-Jul-2005, 06:41
A Compur |Electronic should be a great shuttter. Unfortunately, there are two major problems. If they need work, shutter repairmen don't want anything to do with them because they are electronic and electronic technicians don't want to work on them because of the mechanics involved. The other difficulty is that the smaller sizes operate on batteries no longer available. There are substitutes, but many people lack confidence in them.

This is a great pity, because these shutters were much more accurate than either pneumatic or clockwork types and solved the problem of the two to four second exposure. For convenience, the electronic types went up to 32 seconds. Regrettably, even though precision resistors and capacitors are cheaper than gears, these shutters were priced very high, sold poorly and were soon discontinued. Now, electronic types are universal in the smaller formats, but we in LF are stuck with obsolescent timing mechanisms.

Arne Croell
15-Jul-2005, 07:40
The battery, although rare, can still be bought (same dimensions and voltage, although different internal composition), as it was also used in old Mac computers, e.g.


In adddition, other batteries with higher voltage, e.g. the common PX28 can be used without problem - one needs a spacer to fit the battery compartment, but otherwise they work fine.

Calamity Jane
15-Jul-2005, 08:12
What the hell, it's only money, right?

Since the Wollensak pneumatic is too erratic for film (though it would work ok for tintypes) I just bought a Symmar 300 f5.6 lens in Compur #3 electronic shutter.

I didn't need that money anyway . . . can always make more . . . right?

John Cook
15-Jul-2005, 09:22
In 1970, I purchased the lens you have, as well as a 90mm and 210mm with electronic shutters.

Because they had only one timing mechanism, as opposed to several different sets of springs for different speeds, one could check the accuracy of 1/100th by timing the 1 sec speed. In addition, the electronic mechanism was supposed to be more accurate. I read somewhere at the time that the Compur factory standard for new mechanical shutters was plus-or-minus 25%.

The smaller lenses had the battery attached in a plug-in gray plastic case. I remember it as a standard double-A battery. But then, that was a long time ago. I really don't remember with any certainty what I had for breakfast a week ago today.

The lens you just purchased had the battery and controls in a separate remote control box, connected with a cord. I could set the shutter speed and f-stop, and open/close the diaphragm from behind the camera. Don't remember any controls on the shutter itself.

I finally sold the 8x10 Deardorf outfit (unused) with 4x5 reducing back because there was just no market locally for 8x10 by that time. All the high-rollers had gone "bye-bye" to China.

Don't suppose you got the actual lens I sold in 1980? If so, I genuinely hope you have more fun and make more money with it than I did. ;0)

Ole Tjugen
15-Jul-2005, 12:34
I was thinking of buying that lens, and looked away for five minutes to check my bank account. When I looked back, you'd bought it!

Congratulations - I couldn't afford it right now anyway :)

jose angel
15-Jul-2005, 12:35
In my opinion, the main problem is their dependence on batteries. Depending on the consumption and the regularity of use you have on this shutter, it can be the best option (accuracy) or you can be surprised with an useless lens if you have not spare fresh batteries (or extreme weather). I like to have all lenses&shutters always ready for use; there are some of my lenses I use only twice a year.

Calamity Jane
15-Jul-2005, 12:48
Ole: You want it? I can make you a good deal. Lemme see, I paid this much $$, plus a little profit margin $$, plus shipping $$ , oughtta come to about $$$$$$$$ (snicker!) ;-)

Jose: I am thinking solar cells. I mean, after all, if it's dark, you aren't shooting. If you taking pictures, there's got to be light :-) No dead batteries!

Calamity Jane
16-Jul-2005, 08:33
Matt: Since tintypes have a speed of about 2 or 3, those extended times are very appealing. Indoors, under fluorescent lights, I was running up to 30 seconds. It'd be nice to not have to use a stopwatch.

I'm serious about solar cells! When I get the shutter, I'll check the current draw and see how much it spikes during activation. If the current doesn't spike too much, a few small photovoltaic cells and a heafty capacitor should power the shutter nicely without having to worry about batteries.

John: If the shutter has a remote control box, that'd be lovely! Don't know if this one does - I'll keep my fingers crossed.

tor kviljo
16-Jul-2005, 11:14
I once had a big Voightländer Heliar in a Nr 3 Compur Electronic. Worked perfectly. This model had a gray, cylindrical battery-compartment attached to the shutter body, and inside rested a series (belive 6 cells or something) of about # 76 size cells made up to one element by putting them into shrink-tubing: I guess the battery were ordered by Compur but made up by a number of readily available cells. I used the shutter several years, and it still had that battery in it when I sold the lens, so current draw is probably not big (but I used it on a 8"x10" camera = not to many exposures in that time ...). Very nice shutter, espesially with the longer exposure times. I would imaging you can use lithium-cells as substitute, putting together a several-year lasting substitute once the battery it comes with gives up. Older issues of the Popular Photography (or was it Modern Photography) "how-to" guides had very comprehensive lists of "what battery fit Your photo/cine/lightmeter -equipment" as a standard feature, and I still have a few of these magazines to be able to trace down what kind of battery-type the old equipment were supposed to work with. Email if you want me to check for Your shutter. I never had any electrical release for mine, used just an ordinary mechanical one = worked as it should & no reason to wish anything different. Since the shutter is operated manually when it comes to opening for viewing & setting aperture, no reason to miss any electrical release

(OTOH - now that I have a few lenses in Horseman ISS for my Sinar P, I love that ISS-remote where everything is governed from behind the camera!)

S. Preston Jones
24-Jul-2005, 16:40
This is a good discussion re electronic shutters. I have a 360mm f9.0 Apo Ronar in a Compur #3 shutter which needs repair. Have any of you who have these electronic shutters found a place to have them repaired? The response by Ernest Purdum tends to sum up the experiences I have had trying to get the shutter repaired. The lens is a great lens. Is the only answer to put the lens in a Copal #3?

Bob Salomon
24-Jul-2005, 17:10
"Is the only answer to put the lens in a Copal #3?"

There is no reason not to use a Copal 3 but if you want an electronic shutter for a 3 size lens there is the current Horseman ISS2 system which are actually Copal shutters with step motors and a controller.