Originally posted by IchabodCrane The sensor is just a part that converts photons to a digital signal.
Yes... The most important part, imho. Without the mount you can still ducttape the lenses to the camera. LOL! Something I actually did once in my younger years. I was trying to find out if a suitable adapter would be worth it.
Originally posted by IchabodCrane In theory, it's interchangeable with other suppliers and therefore is not what makes "a Pentax a Pentax".
I wasn't saying the sensor is what brands the camera. Quite the opposite, I was arguing that if it's no big deal to source the most import part of a camera from a competitor, then logically using a competitors mount system would be even less of a problem.
Originally posted by IchabodCrane Perhaps more accurately, the Q and 645 mounts don't define what a Pentax is. For example, if Pentax had never come out with the Q, it wouldn't have meant a thing regarding what people perceive a Pentax to be. With the 645, there are so few sold that they border on irrelevant to most camera users. By contrast, the K mount cameras are the heart and soul of the brand.
Originally posted by IchabodCrane OTOH, the K-mount is what defines the whole Pentax DSLR ecosystem. Without it, what's a Pentax?
Without the K-mount a Pentax camera is still a very high quality tool with very distinct features, very good user interface and exceptionally good ergonomics. If anything, the K-mount system doesn't bring anything to the table other then more restrictions in lens options, noisy screwdrive AF and incompatibility.