Shutter Tolerance

[Bruce Osgood]

I've been testing my LF lenses with a Calumet Shutter Tester.

I'm not suprised by the variations I find but am wondering how much is an acceptable tolerance?

If a shutter fires at 95-105% of the intended speed is that going to give a correct/acceptable exposure?

At what point do you have to admit the shutters' need work?

TIA,

[LabRat]

The Calumet tester allows you to measure 1/6 to 1/3 stop off so you can see if it is in the range where you can compensate for that..

Where it gets difficult would be where the speed was all over the map while trying to shoot, if very unequal spacing of the other speeds, speeds settling at some place where it might confuse you while trying to read the scene, or if the speeds that might vary greatly if the shutter was hot/cold...

Then it's time for the CLA...

Steve K

[Jerry Bodine]

http://www.flutotscamerarepair.com/Shutterspeed.htm

It's a good idea to exercise the shutter two or three times before testing each speed to get any lubricants circulating.

I'd also expect the shutter to perform the same whether the lens is pointed at the horizon or your feet. No reason it shouldn't.

[Leigh]

As that page from Flutot's shows, the tolerance for speeds faster than 1/100th is +/- 30%.

For speeds of 1/100th and slower, the tolerance is +/- 20%.

- Leigh

[jp]

Temperature will cause considerable difference too. For negative film don't worry about small variations

[Jim Noel]

I've been testing my LF lenses with a Calumet Shutter Tester.

I'm not suprised by the variations I find but am wondering how much is an acceptable tolerance?

If a shutter fires at 95-105% of the intended speed is that going to give a correct/acceptable exposure?

At what point do you have to admit the shutters' need work?

TIA,

If your shutter consistently fires at 95-105% you are lucky. The human eye certainly can not detect differences that small in a negative.

[Jac@stafford.net]

If your shutter consistently fires at 95-105% you are lucky.

That would be a miracle to me. With my large #5 shutters I shoot only at a few speeds at their measured speeds which are all way off. Way off!

[Bruce Osgood]

Wow, wonderful response, thanks alot.

And Jerry Bodine, right on the mark.