Originally posted by normhead You are speaking in generalities, exactly what combo are you looking at?
I have a DA300 , I use it with the TC. I like the image quality of the DA300 without TC. With TC, image quality is not so great to my taste. So, I would like to have a sharp 400mm on apsc but Ricoh does not have it. Canon have it but it is not IS. Beyond the Canon 400mm f5.6, it's getting really expensive and heavy. I also considered the DA560 but I'm not impressed with the image quality at this price, it does not seem to be good value for me, the DA560 is almost the price of a Canon 500 f4 that I saw recently in a shop but the Canon is faster and better optically. Then considering the zooms: DFA150-450, no more reach than my DA300+TC, and no much sharper... and the DFA is heavier, so I stay with the DA300 TC combo that I already have. I also considered the Sigma 150-600 S, which I suppose would be a little sharper than the DFA150-450 but still not as good as a prime on apsc body, but... if I mounted a Siggy 150-600 S on a ff body, 600mm f6.3 would be like 400mm f4.5 on my K-3... so that would meet my goal, and the sigma 150-600 is not as expensive as a long prime, but then the Sigma 150-600 is not available in K mount (on a K-1 for example). So, I'm stuck. I recently had a look a the price of fluorite telescope such as Borg + field flatener + T mount... which in essence would deliver a better IQ than the DA560, similar reach, but cheaper and manual focus... I can only conclude that the new Tamron 150-600 and Sigma 150-600 currently are the best reach / IQ for the money versus any other camera brand, but unfortunately not available for the k mount. So, I wait, in case something would change in the future. I pray for Ricoh to drop the price of the DA560 or redo a DFA600 f5.6, then I'd get a K-1 and a DFA600.