I'm wanting to add a prism to my bargain basement RB67 kit based on a Pro SD body.
At KEH I can have a CDS prism with a non-working meter for less than $50 or a plain prism for just over $100. I have never used an in camera meter in MF any way so metering is not an issue.
Is there any reason that the cheaper (non-working) CDS prism would be inferior to the meterless plain prism?
If it is not much bigger than the plain one an you don't mind...... why not get the cheaper one.
The issue is that selling a "broken" prism, even if the meter is broken and not the optics, is harder to sell than a full working one.
Try to check-out why the meter does not work: if it has fallen it could have damaged the optics aswell.
I never made a direct side-by-side comparison with the RB67 specifically, but generally speaking metered prisms show a darker image than non-metered ones. Try both in the shop before taking your decision.
Yes, that's correct too, sometimes even coverage is smaller with CdS than with plain prisms.
Again, though, I didn't experienced this personally with the RB67 as the prism is so huge and heavy that I never really wanted to own one. But with other cameras, you could clearly tell that the viewing performance with the CdS-less prism was much better.