Originally posted by stormtech Agreed - I stopped with the DA*300 - haven't even gone as far as the 1.4x TC.
To me beyond that point is quite a trade off - loosing 1 stop for 120mm more focal length. In my eyes there isn't a whole lot of difference from 300mm to 420mm. So at that point I embrace the challenge to get closer which is a huge challenge around here as my wildlife is truly wild and so very skittish.
But but but... to use digital TV parlance, the 1.4 TC (I presume it's really 1.414...) gives twice the pixels for every object photographed! Twice as many 'extra' as the K-3 does compared to the K-5/II/s! So 3 times more pixels and 1.7 times linear, by going from K-5/II/s to K-3 and the TC 1.4.
Well that's how I finally persuaded myself to get one, anyway! Trouble is, the K-3 part wasn't free... and neither was tha DA*300mm...