Sinar Copal shutter running slow by 20%?

[Dazzer123]

Hi folks,

I'm testing my newly acquired Sinar P2 camera.

I notice the shutter times are not correct and are about 20% longer than indicated.

So an 8 second shutter time actually measures to 10 seconds and a 1 second shutter time is around 1.25 seconds.

Is this within normal tolerances (i'm guessing not!)?

The whole camera is basically in new condition and has been hardy ever been used if at all (no signs of wear anywhere). Although i'm aware that this isn't the best thing for mechanical devices (sitting unused for years).

I guess i have a couple of choices:

• Get the shutter serviced (difficult in my country, very few people working on this gear).
• Adjust my aperture or light (i'm only working in the studio) to compensate.
• Any other ideas?

Thanks!

 

[koraks]

Is this within normal tolerances (i'm guessing not!)?

Yeah, sounds like it, really. It's not something I would worry about, especially if the deviation is consistent. I'd just live with it and keep it in mind when determining exposure. In most cases, the additional 20% of exposure won't hurt anyway, so even if you just ignore the issue, you likely won't experience any issues.

 

[Dazzer123]

OK! I think i'll try to work with it as it is, see how that goes!

 

[BrianShaw]

If I’m not mistaken, the standard is…

for speeds 1/125th of a second and faster, there is a 30% tolerance on either side. For speeds slower than 1/125th of a second, shutter speeds can have an acceptable tolerance of 20% on either side.

 

[Ian C]

The difference from a marked shutter time of 8 seconds to 10 seconds actual time is the same as that from 1 second to 1.25 second, + 0.32 stops.

You can get zero error by closing the aperture by 1/3rd of the distance from the metered value towards the next smaller aperture (next larger f-number).

For most uses, a 1/3rd stop overexposure is trivially small.

 

[Dazzer123]

Thanks guys!