Does it seem evident and logical to assume that the reason for sticky shutters is the use of old technology lubricants? Maybe it would be much better to use the new and modern high tech lubes like TEFLON. There is a product called SUPERLUBE that contains teflon. Would this be a safe alternative? Why do some shutters stick at low speeds and others do not? Is the cause an adjustment or a lubricant problem?

-- John Dorio (john.dorio@ericsson.com), March 15, 2000

Answers

The cause is usually just plain wear and dirt. The slow speeds in a mechanical shutter are governed by a separate gear train for speeds below 1/15th (or 1/10th) second, while still using the same spring for tension. The extra friction of the additional gears eventually causes stuttering or stalling of the shutter. Most shutters are designed with self-lubricating metal combinations, like steel on brass, which have a naturally low co-efficient of friction and do not require oil, but wear does eventually take its toll. Cleaning, and a miniscule amount of lubrication to overcome the wear are all that's usually needed for perhaps another 20 years of trouble free operation. For example, I've got a Compur shutter over 40 years old that still works perfectly well, after a little TLC a few years ago.

The quickest way to ruin a shutter and lens is to indiscriminately spray WD-40, Superlube or anything else into it.

-- Pete Andrews (p.l.andrews@bham.ac.uk), March 15, 2000.

I agree completely with the previous answer. I have been able to rehab several shutters that have sticky slow speeds simply by working the shutter gently , sometimes for hours (it can make some TV shows more tolerable). The lubrication in older shutters tends to congeal with little use, and the working of the shutter seems to "heat the grease up" and get the shutter working again.

"Less is more" when thinking about adding lubrication to a shutter

-- Jim McDonough (jmcdonough@prodigy.net), March 15, 2000.