Can a Copal shutter be adjusted for accurate highest speed? 1/500, 1/400 ?

[pchaplo]

Can a Copal 0 be adjusted to have true 1/500 sec, even if it makes the other speeds inaccurate?

Likewise can a Copal 1 be made to perform accurate 1/400?

Can a Copal 1 be modified to force it to 1/500? Anyone want to try?

I do understand that as stock they are limited to 1/500 and 1/400, respectively, and that they typically are slow by 1/3 to 1/2 step at highest/shortest shutter speeds.

Have you tested yiur shutter speeds? What did you find? Does anyone have a lens 125-180mm with a tested near-accurate high shutter speed? Are you selling lol

What controls the shutter speed? A spring? Several springs? Could they be replaced or shortened for faster shutter movement?

What physically restricts upper limit of a Copal shutter speed?

[Bob Salomon]

Yes, and the mainspring will quickly break! If you need a 1 size shutter capable of shooting at its highest speed for a prolonged period of time then you will need the Rollei Linear Motor Shutter and its hand piece.

[Pere Casals]

Can a Copal 0 be adjusted to have true 1/500 sec, even if it makes the other speeds inaccurate?

Let me ask, why do you want 1/500 speed ?


You can measure actual shutter speed with a shutter tester. This would cost from $15 to $99 at ebay. The cheap ones are a bare photocell that see through the lens, and it is conected to a PC sound input, from the wave you calculate the time. I use that way, but instead comecting it to the sound input I use an USB oscilloscope.

For having a right exposure the important thing is measuring the actual speeds (and you do with that) and checking the shutter always repeats the same time. This is specially important to shot slides, negative film (IMHO) has more margin for errors than with slides.

http://www.kenrockwell.com/tech/expo...rge-format.htm

For studio shots you can use strobes, this would ensure the image is perfectly frozen as your exposure time in practice is ultra short (can be 1/30000 sometimes).

[Chris7521]

I highly doubt you would ever get anything close to top speed. The retarding clockwork isn’t doing anything at that speed. It’s the strength of the main spring that limits top speeds. They just were not meant to do what you’re asking.

[pchaplo]

Hi Bob,

Thanks. Just thinking outside the box. What is the highest actual tested shutter speed for a stock Copal 0, which is clearly my best bet? Can anything be done to slightly improve that to approach the labeled 1/500?

Yes, and the mainspring will quickly break! If you need a 1 size shutter capable of shooting at its highest speed for a prolonged period of time then you will need the Rollei Linear Motor Shutter and its hand piece.

[pchaplo]

For aerial photography.

Let me ask, why do you want 1/500 speed ?


You can measure actual shutter speed with a shutter tester. This would cost from $15 to $99 at ebay. The cheap ones are a bare photocell that see through the lens, and it is conected to a PC sound input, from the wave you calculate the time. I use that way, but instead comecting it to the sound input I use an USB oscilloscope.

For having a right exposure the important thing is measuring the actual speeds (and you do with that) and checking the shutter always repeats the same time. This is specially important to shot slides, negative film (IMHO) has more margin for errors than with slides.

http://www.kenrockwell.com/tech/expo...rge-format.htm

For studio shots you can use strobes, this would ensure the image is perfectly frozen as your exposure time in practice is ultra short (can be 1/30000 sometimes).

[pchaplo]

Hey Chris, I just wonder how close I can get to 1/500 sec with a Copal 0, and if anything can help that.

I highly doubt you would ever get anything close to top speed. The retarding clockwork isn’t doing anything at that speed. It’s the strength of the main spring that limits top speeds. They just were not meant to do what you’re asking.

[pchaplo]

If you are testing your shutter speeds in Copal -type shutters, what are you finding as actual speed at the highest shutter speed settings?
1. For Copal 0, how close to 1/500 sec?
2. For Copal 1, how close to 1/400 sec?

I need to stick with mechanical shutter bc well, I work in the sticks

[pchaplo]

I know that this is not standard practice, but there are undoubtably small somewhat lightly stronger springs that are durable. Not all alternative springs would break. Maybe a watchmaker would know. I dont think that a loaded shutter is a massive load.

[Carsten Wolff]

Have you asked Carol Flutot?