This is not true of the more recent Pentax DSLRs, including the budget K-x. I just came inside from shooting origami boats in the park across the street with mine with the 50/2 SMC-Pentax.
Originally Posted by steelneck
This issue that you raise--backwards compatibility--is far less true of Pentax than Nikon, Canon, or any of the other major players (quality is another discussion which... to each their own ). As noted by Karen Nakumara, who has more experience with these things than all but a tiny percentage of people in the universe:
"The famed "backwards compatible" Nikon SLR system has enough incompatibilities and "buts" to fill an entire wall chart."
But don't take her word for it:
In fact, if you type "nikon lens " into google, "... compatibility chart" is second-ranked behind only "... reviews".