Originally posted by jerry7171 Has Pentax traditionally used the same sized focus screens from the film to digital eras? I have a couple of old Pentax film cameras I originally purchased just to get the lenses from but I could never bring myself to toss them. So they went up on a shelf after that. I don't recall what they are right off the top of my head, but I do know they're old SLRs. If the focus screens are the same size I figured I'd save a bit of time and money by harvesting one and installing it into another Pentax I have my eye on. If not, then I don't mind buying a focus screen and waiting for it to be shipped out.
All of the Pentax DSLR's (up to the brand-new K-1 full screen DSLR) have APS-C cropped sensors, and have correspondingly smaller focusing screens.
If you're adventuresome, it is possible to cut a Pentax film era focusing screen down to size -- there was a thread here not too long ago, I think, about someone doing so with a Super Program focusing screen -- but then there may be shimming issues for you to resolve (no pun intended) (really).
Another possibility is buying a screen already cut to size from eBay or from
Focusing Screen, but you will still have to fiddle around with shims. [And, unfortunately, the excellent quality of Katzeye screens is no longer available now that the company has gone belly-up.]
In at least nearly all cases, though, you'll still likely have metering change issues to mess with (and/or perhaps screen darkening issues with smaller aperture lenses, depending on the type of screen chosen).