Full frame or not ???

There's some exciting times ahead for us all. The FF model will both split Pentax users and bring more into the fold, (or at least retain many more).

It should also impact on the market for high quality aps-c items ... Is it not fair to suggest that aps-c lenses and the top camera bodies will come to represent an even greater bargain than at present?

What it'll mean for me, Nigel, is something wonderful and aspirational, something to desire and dream of, although, of course, ultimately out of reach.

I like living in a world with great stuff like Georgian manor houses, Ferraris, Velocettes, Rolex watches; things which are unobtainable for most, but without which life would be very dull and colourless.

Thank you! You have broadened my world ...I had never heard of a Vellocette before. Now I've got one more thing to aspire to. Lets hope someone makes a designer pannier bag to fit a Pentax Full Frame camera in !

I have the Sigma 120-400 in Sony fit and I have to say the Pentax 55-300 WR is miles sharper and lighter. I also have a Tamron SP 70-300 (Sony fit) that easily beats the Sigma. So unless you REALLY need that extra 100mm I would get the Pentax 55-300.

Lighter, but not sharper.

It's been this way for decades (many decades) with lenses. You get what you pay for in lenses. Minus advances in certain materials, one simply cannot make a lens lighter or smaller. If one wants aperture or optics, then size and weight will become a secondary issue.

Simply take a look at the bet glass for Nikon, Canon, Leica, and even Hasselblad for very clear examples of proven physics.

I don't see why the Pentax 55-300mm couldn't be lighter and sharper than the Sigma 120-400mm. It depends on various factors, including maximum aperture and construction quality and in any event a 400mm is going to have to be a larger heavier beast. It doesn't make it any better.

Pentax used to make lighter, sharper versions of longer telephoto lenses, such as a 400mm f/5.6 which was considerably lighter than the f/2.8 version. And quite possibly sharper.

All I can say is that when I compare the pictures from the Sony A77M2 / Sigma 120-400 and the K-3 / Pentax 55-300 the first thought that crosses my mind is how much could I sell the Sigma for. The output from the K-3 / 55-300 is VERY obviously sharper. The A77M2 also produces much better quality with the Tamron 70-300.

I've just come back to Pentax after bagging K-3 in a recent Amazon sale (had a K10 & K20 previously) and I'm deeply impressed. The k-3 is such a great handling camera and feels like a MUCH more expensive camera in the hand.

With any long lens sharpness depends quite a lot on how steady you can hold it. A lighter lens is easier to hold steady so often it will be better than a heavier lens.

I once tried a 2x TC on a tripod mounted Sigma 150-500mm and even on a heavy tripod with a Novoflex B&S head couldn't hold it steady enough. I put a Novoflex GAKO Forked Joint Long Telephoto Lens Support on another tripod near the front of the lens and the results were about 10x better Obviously only usable for static subjects.

One on ebay.....

The 55-300mm is excellent and easy to handhold even at 1/300th sec.

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