Maintaining shutters

[Ulophot]

Since the days when my concerns were limited to 35mm cameras, I have followed the advice long ago given, to take out the camera periodically during extended periods of non-use and run through the shutter speeds one at time, cocking and releasing several times each. (For lenses, the same with twisting the focus and aperture rings back and forth through their entire range.) I also leave my shutters on B or T, presumably to leave the least tension on springs.

As I was performing these activities tonight on my 645 kit and my two Copals, it occurred to me to ask about an aspect of this. Memory tells me that shutters have at least two "escapements" (correct term?) or mechanical ranges, one for slow, one for faster speeds. I am wondering whether each is sufficiently exercised by a single speed in its range, or whether there is specific value in going through them all. Can you tell I know nothing of the mechanics?

I trust that the same principle will apply to my focal plane shutters in 35 and 645. The 645 one (Mamiya Pro) is electronic, but there are still moving parts; perhaps this one needs less full treatment?

[Jim Jones]

Most between-the-lens shutters do have two escapements. Both types can usually can be thoroughly exercised by using only the slowest speed for each escapement. Focal plane shutters usually have an escapement for the low speeds that can vary from maybe 1/20 to 1/125 second. Exercising it at the slowest speed suffices. I hope Shutterfinger also replies to your question for more and better information.

[Tin Can]

I have more than a few shutters

I don't exercise them on a schedule, but do just before actual usage

Shutters do wear out, as do repair experts, they are thin on the ground