Originally posted by luftfluss In addition to what you've mentioned, a consumer-grade lens like the 55-300 just isn't good enough to handle the pixel density of the 1/1.7" sensor in the Q-S1.
My own personal rule of thumb is, once the superzoom's focal length (the whole 35mm FOV equivalence thingy) is more than twice my DSLR's, the advantage goes to the superzoom. So if I'm shooting a K-5 + 55-300 @ 300mm (450mm FOV in 35mm equivalence), once my superzoom (and I'm talking the good ones) passes 900mm, I'd much rather use that.
From my experiments, I believe this is basically true. Various guys here have gotten some really good pictures with a Q-something, but they've typically used a $$$$ Sigma. My own backyard experiments showed me getting slightly better images with my Sigma 70-300 APO than with my DA 55-300; part of the difference there may be the aperture ring on the Sigma {which I'm guessing works better than the aperture constrictor on the Pentax adapter}; basically "consumer grade" K-mount lenses may not resolve to level of tiny Q sensor pixels. I am absolutely convinced that a native Q-mount 70-300 lens would do the best of any of the contenders listed here, but Pentax doesn't seem to have any interest in entering that market.
If I followed the example of those upset by how the K-1 handles lenses built 1975~83, I would say "sad" every sentence above and then promise to drop Pentax and go to Nikon, but I think there has been too much of that so far as it is {which is why I adopted the Green Button as my new avatar}. I am willing to own two up-to-date cameras at a time. Oct 2014 I briefly considered buying a Canon SX-50, but I couldn't figure out how to meet my other needs with just one other camera. So, right now, my two-camera solution consists of a Q-7 and and K-30; I will continue to experiment to see how the Q-7 can provide better birding pictures for me.
---------- Post added 03-05-16 at 09:41 PM ----------
Originally posted by K-Three I would question the balance of a Q with the 55-300 on it, can you reasonably hold it steady?
A long time ago, back when we had to hand-focus every shot, I learned to hold the barrel of a long lens with my left hand; with that type of grip, I'm not sure a Q is much less stable than a super-zoom is because I basically end up with a camera on the end of a lens ... except that taking a picture requires a longer time on target because of hand-focusing. I solved the problem for me by getting a monopod / walking-stick from MeFoto {actually, at my age of 68, I may have solved two problems at once}