Using OM lenses - aperture control

Hello,

Sorry to mark my first post with a question that's probably been answered before, but search won't let me search for 'om'!

I would like to know, how do you stop down adapted OM lenses? Looking at the adapters available on eBay, they do not appear to couple to the aperture ring and diaphragm linkages on OM lenses.

So what do you do, hold down the DOF preview button when taking the shot?

Not too great when using a tripod to avoid shake! Has anyone come up with a contraption to hold it in? (Wouldn't imagine a rubber band would exert enough force?)

 

Ah right -- so the live view works OK even when you have the lens stopped right down? (Not too dark/noisy?)

 

Thanks!

One more question on a related note -- what about the DOF markings on the lens? I would assume that for equal print size from a smaller sensor, you would want a smaller circle of confusion and so have a narrower effective DOF than you would for a full frame sensor with the same lens, aperture and subject distance.



Is there a simple trick you can do like pretend you're actually 1 stop faster in aperture when choosing which marks to use on the barrel?

 

Thanks .. a full 2 stops, that is a fair amount. I have just checked that with an online calculator and it matches. Just to extend your example a little, your 50/1.4 on MFT also has the same DOF as a FF 50/0.7 (but of course a smaller FOV).

Like Brian I have mostly used DOF preview or bracketing but do use the markings when I wanted it on the hyperfocal distance. It will be helpful to know I choose the markings for 2 stops faster than the actual setting.