Mamiya 645 Moving Coil Electronic Shutter - Does it retain accuracy better than a mechanical?

[loccdor]

Hi,

I'm interested in seeing if my M645's shutter is accurate enough for slide film but I won't be able to mix up the chemicals to process any for quite some time nor afford the expense of sending it to a lab. C-41 and B&W has done well in this camera.

A few questions:

Do you know if this shutter design is inherently more accurate than one that just works on gears, or can it suffer similar shifts in timing as a camera ages?

I will only be using a handheld light meter. Does the discrepancy of T-stop vs. F-stop in lenses pretty much necessitate individual-lens-testing on non-TTL metered shots for E-6?

The speeds I am interested in are 1/60 through 1/500. I am using 4LR44 6 volt batteries, not the silver oxide which is hard to find. Any big problem with that?

Have you ever seen a M645 that exposed images evenly across the frame, but just had incorrect timing on the exposure?

Thanks!

 

[ic-racer]

The only way to know if any shutter will work for you is to measure the cameras shutter speeds.

Weather or not the exposure is even across the film plane will be determined by the relative strength of the opening and closing curtain springs. Again the only way to know is to measure the shutter at each end of the frame.

If you don't have access to a 6x4.5 focal plane shutter tester, you can just use slide film to test the camera.

 

[OAPOli]

In principle the electronic timing is very accurate. But the actual shutter speed depends on the correct balance of spring tension and friction in the rollers, brake, etc. A gummy electronic shutter will run worse than a tuned mechanical shutter. As @ic-racer said testing the speeds would be required.

 

[MattKing]

As the previous posters indicate, the timing may be more accurate, but the shutter speeds themselves may vary from the timing set and controlled by the circuits. It depends on the condition of the shutter.