Originally posted by Class A ...
I think this is a pretty wild speculation. It would mean that Pentax cameras discriminate third-party lenses (I know that in-camera lens corrections only work for Pentax lenses but this is a different matter). This would be a serious detractor for buying Pentax cameras, AFAIC. Pentax needs the third-party lens manufacturers to offer their customers a reasonable set of lenses to choose from.
...
Just speculation ... the point being that if there are lens traits taken into account in the design of the AF system they are likely to be Pentax lens traits. I'm not saying this would be something designed to hurt 3rd parties rather an expression of an attitude where 3rd party lenses are not either discouraged or encouraged as would seem to be the case.
The speculation about chromatic aberrations is based on K-5 AF apparently being sensitive to the color/spectrum of light, and BF/FF in general being lens/copy specific. In general, I suppose (consistent) AF failure is about the AF sensor seeing a different image than the image sensor sees. If one looks at the light path for something that might cause this the AF optics are an obvious suspect.
The point of the speculation, I guess, would be sparking discussion which in the ideal case has results of pragmatic merit, and, failing that, at least intellectual interest. Failing both, we at least have a social thing going
. Failing even that, at least someone looking for thesis material in sociology/psychology/... might benefit
).