It unclear at present just what the focus screen situation is outside of Ricoh's
very explicit statement that the screen is not replaceable. Here are the talking points as I understand them:
- The K-1 screen features the same surface as current model APS-C Pentax cameras (Natural Bright Matte III)
- The screen used on current model APS-C Pentax cameras is deficient for manual focus using even moderately fast lenses. Whether that deficiency carries over to the K-1 is unknown at present.
- Various other model Pentax cameras from the past have been billed as having non-replaceable screen, but that later turned out to be untrue. That being said, those cameras were not made under Ricoh ownership.
- Photos of the pre-production camera reviewed on the Web in the last week or so clearly show what appears to be a retention tab adjacent to the focus screen that is essentially identical to that on the K-3 and other Pentax bodies
- Some have suggested that the lower section part of the viewfinder display showing camera status messages might be in the way. Not knowing how the system is actually built, that is hard to determine, though all Pentax dSLRs supporting interchangeable screens from the *ist series through to current models feature a similar display layout. On those bodies the status display itself is located in a different area of the pentaprism housing and is presented to the viewer through a different optical path exclusive of the prism.
- There is conjecture that the K-1's designers may have opted to fuse the LCD overlay to the focus screen. This may well be, though it should be noted that Nikon cameras have featured a similar LCD overlay for several years on their interchangeable screen bodies without requiring a fused assembly.
Executive summary? We don't know for certain at this point and won't know until some owner or technician (Roger Cicola*, are you listening?) does a tear-down analysis.
Steve
* Cicola is the technical blogger at lensrental.com and has conducted very thorough and enlightening tear-down analysis of recent interchangeable lens cameras and lenses.