Fudging speeds on old shutters

[docw]

To be more exact, perhaps... you had success with one specific design of old shutter.

But a hearty congratulations for finding a shutter that would do intermediate speeds.

Brian, I thought that I would be the last on the block on this, but I guess that it is not well-known. Also, although I have two Kodak Commercial Ektars with these shutters, I guess that there just are not that many Universals around anymore.

[BrianShaw]

I’ll have to try that on my dial-set Compur. The cam on the dial is a smooth (step less) curve, unlike most speed cams on rim-set. I must apologize for not reading your first post correctly... you said dial but my brain thought rim... and my fingers mistakenly believed my brain as it wrote an earlier reply.

[docw]

I’ll have to try that on my dial-set Compur. The cam on the dial is a smooth (step less) curve, unlike most speed cams on rim-set. I must apologize for not reading your first post correctly... you said dial but my brain thought rim... and my fingers mistakenly believed my brain as it wrote an earlier reply.

Brian, I am not completely sure what the Universal should be called (dial? rim?). I hope that the photo (see the link) is helpful.

[BrianShaw]

That would be called rim-set.

[Jim Galli]

Bad idea, works for few shutter types.

Good idea. Works fine with almost all old American shutters. Listen to your Nikon FM at 1/4 second, adjust your old clunky Betax or Alphax or Ilex until the open-close duration is identical. Also works well with old German "Compound" shutters.

[BrianShaw]

Good idea or bad idea, it’s not about good or bad... it either works or it doesn’t... depends on the shutter design. I don’t know of any potential damage that could result from trying.

If it works, that’s cool. If not there are other easy ways to do the same compensation... if it’s even worth doing.

[Pere Casals]

are often designed essentially with steps rather than a mechanism to allow accurate (if any at all) intermediate speed selection.

Anyway there is an exception, Compound pneumatic shutters, as the speed is governed by a tap.

[Pere Casals]

If you have not seen one of these, here is an example.

You can see that there is a quite a distance between the shutter speed numbers. Also, notice that this is a dial. I am pretty sure that this technique only works with dial-type shutters. I tried it on a few others with no success. I seriously doubt that it would work with an RB67. I have two of these old Universals, so this was a great discovery for me.

Of course it is good to experiment like you are doing.

Anyway let me say what I've learned from my collection of well beaten shutters.

First is that the key solution is having a shutter tester ($15 to $100), it is no problem that marked speeds differ a lot from the actual ones, the important thing is that the speeds are repeatable. If you know the actual speed then you stick a label with that on each lensboard and from that you have no problem to adapt the exposure to get a perfect job.

A mechanical shutter was sold brand new with an specified tolerance of +/- 30%, so 1/30 could be 1/20 or 1/40, and this is a full stop. So you need a shutter tester anyway if you want to nail exposures.


Second thing is that it's worth to experiment. I fixed 2 compur shutters by simply spraying a high performance lubricant inside (MicPol based dry thin layer teflon, Interflon Food Lube), now they work like new, and one year later both still conserve a perfect consistency. I don't recommend to do that to anybody, and if you explain that to a proficient shutter technician he will say that this is crazy, and he would be right. But I had 2 shutters that could not be used that was not worth to be repaired, and now both are working like new.

Also I tested that with a Seiko shutter but it not solved the problem, and the lubricant arrived to the wrong place... Well, experimenting also has a risk.

So, my recommendation is that you get a shutter tester and if the speeds are repeatable then use the actual speeds. https://kenrockwell.com/tech/exposure-large-format.htm

[BrianShaw]

Anyway there is an exception, Compound pneumatic shutters, as the speed is governed by a tap.

[Pere Casals]

And it has another refinement: it sounds like music. It's a pleasure to shot it... I feel like a good photographer with it !