Compur Shutter slow and fast speeds

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seany65

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Hello all, I've just bought an Ensign Selfix 20 with 100mm f4.5 Ensar lens in a Compur shutter.

I'm not too surprised that the slow speeds are slow- 1 second and 1/2 second are about twice as long, (going on "Elephant Count"), with the cocking lever getting almost stuck half-way on it's travel back to the "uncocked" position but managing to finish eventually, and the 1/5th and 1/10 also seem slow. The 1/25th and 1/50th are possibly a little slow.

The thing is, I was hoping that with use the mechanism would loosen up a bit and would not get almost stuck in 1s and 1/2s, so I decided to go through the speed range a few times from fast to slow.

When moving the speed dial to 1/250th, the dial seemed to be very slightly on the stiff-ish side and got looser from 1/125th onwards. I fired the shutter about a dozen times on 1s and 1/2s and I don't know if it was wishful thinking or not but there seemed to be a tiny amount of speeding up, then I went up the scale to 1/250th and on coming back to 1s and 1/2s the speeds seemed to be as slow as they were to start with.

I was wondering:

1) Is it normal for a Compur shutter to get a tiny bit stiff-ish when being moved onto 1/250th?

2) Is it possible for the speeds to get closer to their marked speed with a bit of use?

3) Is it to be expected that any possible, slight, quickening in speed for the slow speeds to "disappear" after the shutter has been fired at the fastest speed?

Any help anyone can give would be much appreciated.
 
The old rimset Compur shutters are very sturdy. It sounds like yours needs a light cleaning. There are likely deposits of grime and dried lubricant on the shutter and aperture leaves as well as in the mechanism. The Camera and Restoration site has a good illustrated guide to disassembly of the shutter. You probably will not need to do a complete disassembly, but rather just get the front off so you can brush some Ronsonal onto the internal workings of the shutter.
Regarding the 1/250 setting, when you turn the shutter ring all the way to the highest speed you are engaging an additional stiff booster spring which accounts for the increased resistance at that point.
 
From the web site linked to above, looks as if there is a booster spring for the highest speed. If you look at photo #4, at about 10 o'clock on the outside edge of the shutter, is a heavy coil spring around a screw and right above the metal dog leg part. As you rotate the rim to engage 1/250, you are compressing this spring. That is the increased tension you feel.


Do what Mike said and you'll get the speeds back.
 
Yep, Dan has it right on the spring. I was in the process of adding a sentence on that when he posted his comment.
I opened the Compur on my Zeiss Ikon Maximar to be sure I knew what I was talking about. Getting that top plate off the shutter involves removing the very small screws that hold on the aperture scale and maybe a logo badge as well. Mine also had another larger screw under the aperture scale that needs to come out.

You then need to rotate the cover plate to line up the three tabs with the openings so that the plate can be removed. Sometimes the tabs are a little sticky and you may need to use a pointed instrument in the screw holes along with a knife edge to help lift the plate out. That is probably as far as you need to go with disassembly. As long as the cocking rack is in place you can operate the shutter to test the effectiveness of your cleaning efforts.
 
Have it cleaned.

Two things to consider. Slow speeds should be accurate. Fast speeds are also accurate , BUT time is measured while full open. So if you use small F stops and fast speeds over exposures will happen because the time of blades opening and closing are not added to the full open time measured.

When I first started in early 1960, Kodak warned of this in the film instruction sheet that came with High Speed Ektachrome.
160 was the box speed shows you how things have changed.
If I recall under 1/2 stop was the recommendation of 35 mm cameras with leaf shutters.
 
Thank you to everyone for the replies and the info.

I had hoped just a bit of use would sort it out, but it seems probably not.

I did wonder if there should be a bit of extra tension for the 1/250th, but as none of my other folders (with a Tempor, an Epsilon and two Synchro-compur shutters) have speed rings that get a bit stiffer when going to the top speed I wasn't sure if it was to be expected.

I'm fairly sure I'll be far too chicken to try to fix it myself, as I am a complete clumsy clot of a cack-handed buffoon when it comes to that sort of thing, so I'll have to pay to have it worked on.

Thanks again for the help.
 
Just a word of caution, even if you pay a lot of money to have a shutter of that age serviced, don't be suprised if you don't achieve the fastest speeds as engraved. Cleaning, and a touch of watch oil if applicable, yes, but aged springs and wear in the mechanisms ... My experience with many Compurs, Prontors, Epsilons, Kodaks ...
I measure the actual opening times with one of those optical jobbies you plug in to your PC microphone port, and set the exposures accordingly for that camera.
 
Thanks for the links citizen99, I've just put them on my "watch" list.

I'm a little confused though, the tester measures light not sound but needs a sound editing program on the pc to work?
 
seany65 said:
Thanks for the links citizen99, I've just put them on my "watch" list.

I'm a little confused though, the tester measures light not sound but needs a sound editing program on the pc to work?
Click to expand...
No problem, there is a program called Audacity that is free to download, just google about it. Runs on Windows, Mac OSX, Linux ( I have used it on the latter).
https://www.audacityteam.org/


You could no doubt find others.


Some specimens here
https://www.flickr.com/photos/43334883@N03/albums/72157691747415032


The tester's photocell converts the light to an electrical pulse that the sound card can use. Don't worry about those speed displays that are such that the elecrical decay after each transition can be seen. It's the 'sharp' transitions, dark-->light and light-->dark respectively that are significant.
 
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Bit late to the party here but I back up all that has been said. They do gum up, and cleaning (done properly, not just squirting lighter fluid in) will sort it out. Slow speeds should work fine - I have a 1937 Compur Rapid that has the best set of speed figures I have seen, except the top two speeds. These run at about half speed, which is fairly normal - a consequence of age, and they're not regulated, the shutter is running at full speed (just with a second spring for top-top speed). They're not hard to work on in general though.
 
I'll have another go at a reply I've just typed but lost due to having to login again even though I ticked the remember me box:

Thanks for your reply and the info johnnyrod.



I recently found out that it has a self-timer (not for 1/250th though), in the form of a pin you have to move back after tensioning the shutter and you then have to tension it again.

So I tried it and the tensioning lever took so long to get to the position at which the shutter fires, it gave up.

Would the cleaning sort this out too, or would that be another job?

While I probably won't use the self-timer, it would be nice to have the whole thing working properly.
 
I've just taken it in for a service/clean. It'll be about a month before I know if the "trouble" was just dirt or gummed up a bit etc. I'll also find out if the self-timer is working after the tech's been at it.
 
I doubt the self timer has affected anything but it's hard to tell without seeing it. Where did you send it?
 
seany65 said:
I've just taken it in for a service/clean. It'll be about a month before I know if the "trouble" was just dirt or gummed up a bit etc. I'll also find out if the self-timer is working after the tech's been at it.
Click to expand...
Unless the mechanism has been forced, it's unlikely the self timer can't be persuaded to run well. Although timer mechanisms in older shutters are sometimes demonised by users who claim they're inherently untrustworthy and will jam up a shutter if used, the reality is that their gear trains are just a simpler version of the escapements used for controlling shutter speeds. Rather than being a combined inertia/retard escapement they run at a single speed with their pallets permanently engaged, hence, they're actually less complex.

They will often manifest a failure to run off fully, but this typically will only reflect a lack of use, exercise, and a need for servicing. If the one fitted to your shutter is not running off it will only be because, like the rest of the shutter, it's fighting against the additional drag of old, oxidised, organic-based lubricants which are no longer reducing friction but actively increasing it, at the expense of reliable running. Getting the shutter competently serviced should include the timer escapement being cleaned and lubricated, at which point, I'd be quite surprised if it did not operate flawlessly.
 
Johnnyrod,

I took it into a shop in Manchester called "The Real Camera Company". I've been going there since it was "Nobby's Cameras" in the 80's. They, or rather the techs they use worked on my Super Solinette and my Super Regent.

If it works when I get it back, I'll have to have a long sort through their "small" filter/lens-hood drawer, not only for ones that are 35mm push-on, but also that somehow avoid the stop-pin thingy that is so close to the lens that ordinary push-on filters and lens-hoods can't fit. It's a nice camera and the unloading method is Sooo much better than on my selfix 16-20, but it's going to be a nightmare finding hoods and things.


Sarcophilus,

While I know nothing about self-timers, I do think that at least some cameras that have self-timers that aren't working properly may have been set while the shutter is on a disallowed speed and so were damaged to some degree. Perhaps some of the users realised it was set at such a speed and changed it to an allowed one and damaged the shutter or self-timer that way?
 
seany65 said:
Johnnyrod,

I took it into a shop in Manchester called "The Real Camera Company". I've been going there since it was "Nobby's Cameras" in the 80's. They, or rather the techs they use worked on my Super Solinette and my Super Regent.

If it works when I get it back, I'll have to have a long sort through their "small" filter/lens-hood drawer, not only for ones that are 35mm push-on, but also that somehow avoid the stop-pin thingy that is so close to the lens that ordinary push-on filters and lens-hoods can't fit. It's a nice camera and the unloading method is Sooo much better than on my selfix 16-20, but it's going to be a nightmare finding hoods and things.


Sarcophilus,

While I know nothing about self-timers, I do think that at least some cameras that have self-timers that aren't working properly may have been set while the shutter is on a disallowed speed and so were damaged to some degree. Perhaps some of the users realised it was set at such a speed and changed it to an allowed one and damaged the shutter or self-timer that way?
Click to expand...
You're quite right that certain designs have incompatible settings. Eg Compur Rapid types may prohibit use of the self timer with the maximum speed that needs a booster spring, (1/400 or 1/500, for instance). Bulb, too, from memory. If a mechanical failure has been caused by disregarding the maker's instructions on such matters—this would fall under the category of "Unless the mechanism has been forced..." in my previous post.
 
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