View Full Version : Exercising lenses

Martin Feldman
14-Dec-2000, 00:06
How important is it to periodically "exercise" large format lenses? Is there an easy way to tell if there is a problem from lack of use? Thank you.

Sean Billy Bob Boy yates
14-Dec-2000, 01:23
Presumably you mean to exercise the shutter?

It depend on how old your shutter is and what design. I don't worry about my Betax's but the Ilex's I take out the night/day before I hope to use them and run them through the speeds - spending more time on those speeds I know are slow - until my wife complains. Then I move to another part of the house.

The easy way to tell if there is a problem is to set up for that once in a lifetime shot, and listen for the shutter to stay open too long.

14-Dec-2000, 01:36
The easiest way to check your lenses is with a Calumet shutter tester (~$80.00). Learn to use it and test your older lenses every 6 months or so. Don't worry about the accuracy of the shutter (they'll all be off by some amount) it's the consistancy that you're looking at. If the speeds vary by more than +/-10% in the course of 10 firings it would be a good idea to exercise that shutter 50-100 times and retest it. If it's still flakey you may want to have it cleaned (it will only get worse in cold weather).If you work in B&W you can probably survive that much variation - just remember it will get worse with time and in lower temperatures. If you use your shutters much above 1/60th you may want to note the actual shutter speeds at the apertures that you use since the actual shutter speeds will be propotionately slower with faster speeds and smaller apertures (@f16 it wouldn't be unusual for a shutter to deliver an actual 1/200th when set at 1/400th).


14-Dec-2000, 10:49
Is shutter accuracy an issue with new lenses? My lenses are all recent (i.e. 3 years old or less). I generally hit the shutter release a couple of times before making the exposure, just in case.

14-Dec-2000, 13:00
Danny - There are tolerances to any manufactured item. Shutters can be "off" by up to 25% and still make spec. (that used to be the number - I'll have to do some checking to find out if the numbers have changed). Also shutters are spec'd at full aperture - if you use fast film and high shutter speeds/small apertures the shutter will run slow due to simple physics. If you are like most people and use your shutters at 1/125 and slower the speeds are generally within +/-10% on newer lenses - but it's not a given. I would recommend the Calumet shutter tester to anyone who is seriously into photography. Don't want to throw another wrench into the works but how sure are you that the aperture markings are accurate on your shutters? Just something else to think about.