Hi, I have long been meaning to check this with some of my most often used lenses, but something has made me think it is now necessary rather than desirable (perhaps). The photos I have been taking with my Sigma 10-20 (original version) on the 12.3Mp GXR are considerably sharper than those taken on the K5. The results from this lens on the K-5 have always impressed me, but they have needed some sharpening from NIK before looking spot on. On the GXR, the results are even better, which suggests that the lens is not focusing spot on on the Pentax perhaps. On the other hand, of course, the A12 Mount (Leica M with Novoflex adapter) on the GXR has no anti aliasing filter and I wonder if that is the reason. Interesting, I must have a closer look at this. More fuel to suggest getting a K-3 is moving up the 'I want one now' list. How do i convince my Financial Controller though? A weekend away? A Bunch of roses? A box of chocs? All three?