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swmcl
23-Feb-2019, 02:41
Howdy all,

Is the aperture mechanism on a series of shutters the same for all instances of that shutter ?

ie. If I have a lens that fits on a Copal #3 and it comes from the factory with an aperture range of X to Y and another lens also on a Copal #3 with an aperture range of J to K, are X and J both the same physical opening at the aperture (and Y and K also) ?

Or are there Copal #3 shutters out there with a whole range of different physical aperture ranges ?

I don't have enough examples of the shutters to be able to answer the question.

Cheers,
Steve

Oslolens
23-Feb-2019, 03:17
Might be close for Copal #3 for similar focal length, but not for smaller shutters where a 150 and a 75mm use the same shutter Copal #0. My 150mm Sironar-w f5.6 uses Copal #1, and I can switch to razor sharp Copy-Claron lens cells, but max aperture for the latter is f9, so I have to think before setting the aperture.

Big Wehman, Toyo 5x7" and a small Chamonix

Bob Salomon
23-Feb-2019, 05:52
Yes the physical openings are identical but the scales are not. The scales are lens specific.

swmcl
23-Feb-2019, 12:17
Thanks Bob,

I was hoping that would be the case. (Yes I realise the scales will suit each lens ...)

And I assume the manufacturer of the aperture mechanism would allow a full movement of the lever. (It isn't possible to tweak the accelerator to pull a few more 'g's ...)

Thanks again.

(Sorry Oslo I'm not understanding your explanation. You may know also.)

Bob Salomon
23-Feb-2019, 13:19
Thanks Bob,

I was hoping that would be the case. (Yes I realise the scales will suit each lens ...)

And I assume the manufacturer of the aperture mechanism would allow a full movement of the lever. (It isn't possible to tweak the accelerator to pull a few more 'g's ...)

Thanks again.

(Sorry Oslo I'm not understanding your explanation. You may know also.)

The main spring can be tightened but shutter’s life will decrease significantly.

Around 1990 a company called American Traffic Systems in Arizona made a traffic camera system but was having some problems with the cameras they were using (Hasselblad). The first problem was that they needed the fastest possible shutter speed to synchronize with the flash unit they used but the Hasselblad shutter couldn’t come near 1/500. The second problem was that the shutter’s operational life when always fired at 1/500 wasn’t very long for a camera that would be hung on a pole and fired automatically and unattended.
We were the Rollei distributor at that time and they tested the Rollei PQS leaf shutter that was a linear motor leaf shutter that went to 1/1000 at any aperture with full flash synchronized. They found that this shutter reached much faster actual shutter speeds without modification so they built it into their camera.
They found that while the Hasselblad shutter would fail at 1/500 after a few hundred exposures the Rollei shutter performed to spec in excess of 100,000 exposures!

Their testing was done on traffic cameras installed in Australia. So you might have run into a picture, or two, from them!

swmcl
23-Feb-2019, 19:22
Ahhh ... don't get me started ...