Sony and Pentax claim that their sensor-shift image stabilization allows for the implementation of such technology even with lenses older than the technology itself. However I have been thinking about it, and do not understand how it can work with every available lens fitted to a given body with stabilization.
A 0.05 degree camera shake will surely seem more significant on a 100mm lens than a 50mm one, so it calls for a larger sensor shift for compensation. However, what about lenses that do not transmit focal length data to the body? I am in search for a DSLR and I've been keeping an eye on the Pentax K-X. How will this body work with a Pentax-A SMC 50mm f/1.7 that "doesn't digitally transmit focal length data" ?