View Full Version : How do you adjust a Copal No. 3 shutter (1 stop slow @ 125th sec.)

Will Thompson
27-May-2007, 14:20
4 of My Copal No. 3 shutters are 1 stop slow @ 15, 30, 60, and 125th sec.

Any help would be most appreciated!

Jim Noel
27-May-2007, 14:33
If you don't know how to make the repair the only thing to do is send it to a good shutter repair shop such as Flutot's.

27-May-2007, 14:48
If you do not have any experience in working on lenses do not even take out the screwdriver. I did so once, I work on intricate machines for work, and discovered a couple of things.
1. There is a city of parts that all move and more springs than you can believe.
2. You can ruin a lens so that when you do get a back at about $150.00, or more, it will not be perfect.
3. For $75 and a little lead time you will get back a good lens that is a joy to use.



Jason Greenberg Motamedi
27-May-2007, 14:54
Most if not all Copal shutters are slow at their top end. So long as they are consistant it is not a problem. I have a little sticker on each of my lensboards which reminds me of the actual speeds, and I simply make corrections at exposure.

If you haven't taken apart a shutter I would suggest that a Copal is NOT the way to start.

Will Thompson
27-May-2007, 15:48
I guess I should have mentioned that I have an extensive background in such devices and only need the procedure to adjust the hi end timing.

27-May-2007, 16:35
There are more frightening shutters to get into. But if you really want to...

when you open the shutter you will see a cam on the shutter speed ring that has "notches" associated with the marked shutter speeds. There is a follower from the timing mechanism that traverses the opening of this cam. This follower will traverse the gap at a specific location for each of the marked shutter speeds. The amount of space traversed determines the time the shutter will remain open. To increase the speed, file the opening bigger. To reduce the speed, peen the cam to close the opening. Good luck!

27-May-2007, 16:36
p.s. If the shutters are slow at most speeds, it is likely that a good cleaning and lube job is really what they need.

Will Thompson
27-May-2007, 18:31
p.s. If the shutters are slow at most speeds, it is likely that a good cleaning and lube job is really what they need.

Thanks Brian.

What is the preferred cleaner and lubricant?

27-May-2007, 18:53
What is the preferred cleaner and lubricant?

The best... why that would be a 50-dollar check written to Carol Miller at Flutot's Camera Repair. ;)

Seriously! :)

paul stimac
27-May-2007, 19:16
If all 4 are off the same, then maybe it's your meter that's off? If the meter is good and you want to be cheap about it, just compensate when you shoot. That is, if your meter says 15th shoot a 30th, or close down a stop I suppose that this what you are already doing....

As far as working on them yourself, be careful. I tried this and failed miserably. I wish I had spent the $50 to have someone else do it.

Will Thompson
28-May-2007, 00:57
Paul, Yes My Calumet shutter tester is VERY accurate. It shows my T90 to be within 1/6 of a stop from 125th to 4 seconds. What little variance that it has I attribute to the T90 age. I tried My EOS 1Vhs but the shutter has a constant speed with the back open.

I have had my Century B&L shutter open down to the shutter leaves and back together with the only problem being the bad mechanical design. (Mounting it warps the housing enough to need a complete overhaul.) The Copal No. 3 is a thousand times better!

This is the type of thing I do all day long at my day job.

Shutters are easy, just remember to open them in a gallon ziplok bag or you will be making replacement springs all day long!

Pete Watkins
28-May-2007, 00:59
I'll second Flutots. The service that I recently recieved was superb and I wouldn't hesitate to use the company again. It was well worth the cost of sending the shutter across the pond.

Turner Reich
1-Jun-2007, 20:01
Go for it, it'll be an experience you will never forget and one that you will tell everyone about for years to come.

Really, don't even bother, If you don't have the tools or if you do have the tools then you need to know how and If you did know how then you wouldn't have to ask here. I suppose asking though is a way to find out if it is easy or possible. It's neither.

Will Thompson
3-Jun-2007, 11:27
it'll be an experience you will never forget and one that you will tell everyone about for years to come.

I doubt it.

Now then, Repairing a Resonex MRI machine without a service manual or schematic on 6 different occasions all being different failures is something I still mention from time to time.

3-Jun-2007, 19:12
Mr. Thompson let us all know how you come out on it. :D

Take Care,

4-Jun-2007, 00:30
As far as I know, Copal shutters times are not "adjustable" per se. They were designed for mass-production and are made to a tolerance of +/-20% on the speeds. This may be more information than you want or need, but sometimes on the speed setting ring (an internal, punched sheet metal ring with steps that control the timing), you see grooves where the metal has been punched to push it out a bit and tweak the speed. As others have noted, speeds that are too slow are often due to dried lubricants. If you're mechanically inclined and like taking things apart, it's not terribly hard to get at the insides, but a CLA is worth it to do the job properly.