Originally posted by Winder What we refer to as full frame today is actually half-frame.
No, please, that's just not true.
Whether a sensor is a crop sensor or not is with respect to the format the mount was designed for.
The K-mount was never designed to work with 70mm film. It's native image format is 36mm x 24mm and any sensor not utilising that image size is a crop sensor.
In a similar vein, while some people claim that "MF" refers to a number of format sizes and that it is therefore not justified to refer to the 645D/645Z as cameras with crop sensors, it is clearly the case that the original film 645 used a larger image format and that the 645D/645Z mount is designed for an image format that is larger than that these cameras currently support.
"Full-frame" does not have any absolute meaning across camera systems, but it surely is not a term with an arbitrary meaning.
FWIW, I applaud Ricoh for their recent decisions and in particular for the K-1. Ricoh is not serving "side-dishes" at all. The K-1 is not everything to everyone but no camera is. It would have been nice to get an even better AF system (mainly to shut up the reviewers, AFAIC) but the K-1 is a fantastic camera as it is.
Regarding the Tamron rebadging: I think one would be very hard pressed to find any differences between Tamron glass and "Pentax glass" (do they still use Hoya glass?). In particular, I don't think that coatings make a lens. The optical design and mechanical constructions are the same for the Tamron and Pentax versions and I feel those are what makes or breaks a lens. Yes, modern Pentax coatings are great but the Tamron coatings aren't terrible, are they?
I understand and support Ricoh's decision with the Tamron collaboration but claiming that this is significantly different from rebadging is going too far, AFAIC. It is nice that we have access to all the Tamron developed lenses but I'd prefer Pentax to do their own designs and let users buy the original Tamron lenses in K-mount. Again, I'm 100% OK with the current strategy as an FF lens development plan but for the future I think it would be great to see only genuine Pentax designs from Pentax and get independent third-party designs from Tamron and Sigma on top of those.