View Full Version : A Lesson In Shutters

8-Sep-2006, 13:54
Nope, not offering one...rather hoping someone can offer me one!

What's in a shutter? Copal, Ilex, Compur, Universal.... does it matter what shutter a lens comes in? Are there certain shutters to avoid? I know that some may have different sets of speeds than others, and some shutters may come with a flash sync, but is that all that sets them apart?


Kevin Crisp
8-Sep-2006, 14:09
I don't think anything you are going to get anyone to type can come close to the illustrated information on the SKGrimes website. That being said, as an accidental collector of old shutters, I'll add my opinions: (1) ACME -- clunky surprisingly accurate and reliable after a professional CLA. I've never had one that couldn't be fixed (2) Compound -- I've had one really old one that could not be repaired. Old as made in 1909. Others have been OK after a CLA. These are amazingly light weight, low vibration, quiet. (3) Compur -- highly complex and intricate, baffling to the DIY worker, parts are a problem for some, maybe all since they are now out of production, a professional CLA has brought all of them back to life, they do get gummed up with age (4) Copal -- Essentially impossible to avoid on modern lenses thanks to the demise of compurs, the only ones I have had to have cleaned and worked on were 20+ years old. (5) Prontor -- no experience or opinions (6) Volutes -- maybe sometimes somebody can get them to work but they will break again soon (7) Supermatics -- funky looking but decent and reliable if not screwed up by DIY repairs. If a spring breaks you're in trouble. Rapax -- Reliable and accurate.

Ole Tjugen
8-Sep-2006, 14:47
Compur - produced over a period of 80 years, this is a common name for a whole lot of very different shutters. The coarse division is into dial-set and rim-set Compurs, the rim-set being introduced around 1932. The dial-set Compurs are remarkably easy to fix, but there are no spare parts available. Rim-set Compurs are also a lot of different shutters, the differences between which may only become apparent upon opening. I'm familiar with three of the "variants", the reat I would send to Flutot's.

Compound shutters were the "big sister" of the Compur. In sizes from 3 to 5 they were produced well into the 1970's. They tend to either work very well, or not work at all. Repair is worthwhile - when they do work, they're great. It took me a year to find a barrel G-Claron 355mm f:9 for Compound shutter - I had a good #3 to mount it in, and I'd far rather have another lens in Compound than my first Copal.

Ole Tjugen
8-Sep-2006, 14:54
A bit more:

Before about 1930, the shutters were made to the lens-maker's specification. That means there are an amazing lot of different sizes, threads and whatnot. Dial-set Compurs should always be original, there are too many versions to trust correct mounting otherwise.

"Standard sizes" started with the rim-set Compurs. There are still special versions, but nowhere near as many as before. Schneider specifications seem to have been the basis of the standardisation, with Voigtländer being the first to agree. I sitee haven't found a Schneider or Voigtländer lens mounted in an "undocumented" shutter.

Vario, Ibsor, Prontor etc.: I try to avoid these. Some Prontors are good, and I've got a Vario shutter which has worked perfectly for more than 50 years. But I still prefer to avoid them if possible. ;)

Steve Hamley
8-Sep-2006, 14:59
S.K. Grimes site will advise you to avoid dial-set Ilex shutters.

Otherwise, just avoid really old shutters in bad shape because they may not be repairable.


Oren Grad
8-Sep-2006, 15:07
Here's the entry point for the SK Grimes shutter pages:


The only correction to these is that the Compur shutters are described as still being in limited production. This is no longer true.

If you're looking at recent main-line plasmats (e.g. Sironar-N and later, Symmar-S and later) and anything else sold new within the last 20 years, almost everything you find is going to be in a late-model Copal, and there's just not much to think about. Very occasionally you'll see something in a modern Compur, and rarely you'll encounter a lens in Prontor Professional. If you're shopping overseas as well, the late-production Compurs and Prontor Pros are a bit more common in Europe than here.

If you're looking at old lenses, all bets are off, and you could spend the rest of your life filling your head with all the legend and lore... ;)

Ernest Purdum
8-Sep-2006, 15:47
If you use flash, old shutters can be a problem (even though the first flash synched shutters were made before 1900). They are apt to have no synch or connectors which can be a logistics nuisance.

Patrik Roseen
8-Sep-2006, 15:48
Trying to cut costs while building my set of LF lenses I have either bought empty shutters needing repair (lubrication) and lenses in barrels or in sinar-DB mounts (which I do not use), and occasionally complete sets where the shutter has been said to be non-working, sticky etc.

The way to get into the shutters varies, and as one has managed to do that, the difference in complexity of the shutter becomes obvious...the most complex one I have repaired was a synchro-compur where the main spring was broken.

My experience is that as long as one looks for shutters in copal-0, copal-1 and copal-3 sizes there are many both new and used to choose from and they are highly standardised in terms of thread size and depth.

NOTE: I say below that shutters can be triggered while open...this is something I found was possible while I took the RISK since I needed to understand how the shutters move and where lubrication was needed. I have not had any access to repair guides so this was my way to understand how they work. I DO NOT RECOMMEND YOU TRY THIS ON MODERN EXPENSIVE SHUTTERS OR RARE OLD ONES...THOSE I MYSELF HAND IN TO PROFESSIONALS FOR CLA!

NOTE: Lubrication does NOT mean pouring oil into the shutter. Take the tiniest screwdriver you can think of and put a tiny amount of lubrication on the tip of it and then touch the place you want the lubrication to land on.

Here are some of my thoughts about different shutters:
SynchroCompur - takes some figuring out to get into (actually requires a special tool if unlucky), very complicated with many small pieces and springs all over the place, even the x-sync is complicated...but probably very consistent or they should not have been made this way. One need to be very careful cocking and triggering this shutter while open. Modern x-sync connection, some do not have T-setting, some do. The older ones have a lever which you push while triggering the shutter...it will then stop the shutter from closing...shut it by pushing it back again.

Rapax - easy to get into, quite simple inside, old type of x-synch connection, T setting and lever to open aperture for focusing. If sticky there could also be a problem that the T setting mess up because the inside does not travel fast enough, easily lubricated. Can be cocked and triggered while open.

Copal-Polaroid (Self cocking) - quite simple shutter both to open and understand once inside. Can be cocked while open. Comes in different fashions, some have inbuilt apertureblades but many requiers that the lens (tominon) includes the aperture. The ones I have seen without inbuilt aperture comes with focusing lever the others have the T-setting instead, modern x-sync connection. I have not tried fitting any other lens than Tominon into this type of shutter.

Dial-set Compur -The most recent shutter I repaired was an old compur which came with a tele-xenar 270mm from the 1930's.
All screws on the front of the shutter need to be removed regardless of what they are 'holding onto'. The time dial includes some 3-4 parts that need to be disassembled carefully so that one can remember how they should be stacked back when reassembling them (The parts are under the dial-plate). Can be cocked and triggered while open (but be careful some parts are loose and are normally held in position by the front plate)
This is a robust shutter inluding many large metal 'arms' in a clever fashion. The length and size of these things means that there could build up a lot of friction if not clean and lubricated. If the shutter only fires on one speed (fast speed) it is probably due to friction...the clockwork never gets into action since the shutter mechanism just travels by without it having a chance to stop it and run according to the dial set.
This particular one had some type of paper-like material for the aperture blades so I had to be very careful cleaning the shutterblades not to damage these aperture blades. The shutter has B and T setting and the shutterblades need to be clean for these to work...If the shutterblades get stuck in B or T position, I managed to bring it to life again by moving the setting to (I/M) while cocking the shutter and then trigger it (otherwise it get's stuck in B or T position).

Self-cocking Alphax - Easy to get into and understand once inside although not too obvious, can be triggered while open. Has B and T setting. Mine does not have any X-sync connection. The cable release need to be thick and long to really make consistent firing. If the cable release is too short it might only cock halfway and the shutter time will only be half of what you set it to be or it might fire when you release the cable pressure.

Prontor-S - This is a shutter that I really like in Copal-0 size. For some reason it does not seem as if LF-people have understood that this one exists and used ones can be found at prices of USD18-30. I have mounted a convertible Symmar 135mm
and a SuperAngulon F8/90mm into two of these (requires that you make your own aperturescale on them). It is simple to get into and can be triggered while open. Easy to lubricate and get working. (The ones I have found have only had problems with stickyness). It has modern X-synch connection but lacks T setting and prefocusing lever...but this is easily solved by locking the cablerelase in B. EXTRA FEATURE: It has a selftimer!!! I think these shutters came off 6x9 folding cameras.

So yes there are differences...and many more shutters than what I have listed above.

8-Sep-2006, 16:05
Here's one how-to link for a few of the shutters mentioned above. Quite informative even if one doesn't repair shutters: http://pheugo.com/cameras/index.html

8-Sep-2006, 17:20
Thanks, Guys. Sheesh, I guess I didn't know the breadth of shutters out there. Sounds a lot like the hundreds of delicate movements that go into 20th century watches. Funny, when I first started looking at lenses I used to chuckle when the description would say, "...shutter is a bit sticky at slower speeds." I think I had this idea of popping one open and hosing it out with WD40, and PRESTO!

With the knowledge you just passed on, I'll be looking for lenses with shutters that work or have had a recent CLA, and if a problem is encountered I'll be sending it out to a professional. Don't get me wrong, I have the passion, spirit, and curiosity needed to open it up, but then I'd just be mailing a bag of parts off to someone, if I didn't lose a few on the floor. ;)

Ole mentioned dial-set vs. rim-set. What's the difference? I'm picturing it has something to do with the placement of the shutter speed and aperature controls...


Patrik Roseen
8-Sep-2006, 17:36
...With the knowledge you just passed on, I'll be looking for lenses with shutters that work or have had a recent CLA, and if a problem is encountered I'll be sending it out to a professional. Don't get me wrong, I have the passion, spirit, and curiosity needed to open it up, but then I'd just be mailing a bag of parts off to someone, if I didn't lose a few on the floor. ;)

If you find an add talking about a sticky shutter...it usually only requires some lubrication in the right places...you do not need to remove anything than the top-cover. So there is nothing that will fall to the floor.

...Ole mentioned dial-set vs. rim-set. What's the difference? I'm picturing it has something to do with the placement of the shutter speed and aperature controls...
A dial-set shutter has a small wheel on top of the shutter which you turn in one direction. There are markings on the weel for the speed it will set the shutter to.

A rim-set shutter is one where you grab the shutter at the edges (rim) and turn the whole wheel which is located underneath the frontplate.