Well, I'm very close to jumping on the K10D, to replace my ist DL. I wanted to get the K100D, but I really want the faster, bigger buffer - I'm even talking myself into doing the RAW+JPEG thing.

And, bet of all, my better half is tired of me agonizing over what long zoom to get, and has basically said, "Get whatever you want! We can afford it!"

So, what long zoom to get with the K10D? I have the tamron 70-300mm, and it's OK stopped down to about f/8 - but I often need more reach. So, I'm considering the following:

Sigma 135-400 f/4-5.6 APO DG: Currently $569 USD
Sigma 170-500mm f/5-6.3 DG: Currently $668.31 USD
Sigma 50-500mm f/4-6.3 EX DG: Currently $968.57

I'm a bit concerned that the 135-400 may not be enough; I've used the 70-300mm with a Tamron 1.4X TC (420mm), and I could still stand to have some more reach - sometimes a lot more. Plus, the AF on the Tamron + 1.4X TC is very slow, and hunts in all but the brightest light.

Does anyone know how the Sigma 135-400 does with a 1.4X? I would suspect that it too is slow.

I'm also concerned about the softness of both the 135-400 and the 170-500; I seem to read conflicting reports.

Should I just shoot the works and go for the Bigma?

I'm tempted to wait for the Pentax 55-300 or 60-250, but heaven know knows when they're gonna be released, and how much they're gonna cost.

I've even thought about the Sigma 70-200 f/2.8, but I can't see how that's gonna be long enough, even with a 2X TC. Plus, no one seems to have it in stock.

If you could spend nearly a grand on a long zoom lens, what would YOU get? Please note: I need an AF zoom, no primes, no MF. I have some primes, and more than a few MF lenses (including a Super-Tak 300mm f/4, and a farily decent mirror 500mm f/8), but for what I want to use this for - deer, squirrels, birds, bats, even whales, sports from the cheap seats, etc. - I really need AF, and I need some zoom range, not a fixed focal length.

Thanks in advance for your advice, opinions, etc.

--Greg

P.S. While I really like Pentax, especially the SR in the K100D and the K10D, I'm not married to the brand. So, if you honestly think a Canon or Nikon would be the better way to go, speak up! I'm thinking that it would be cost-prohibitive: To get IS/VR in a zoom lens that goes out to 400mm or 500mm has GOT to cost in the thousands. I've been given the go-ahead to spend up to two grand for both a camera and a lens. I have still toyed with the idea of a Canon 30D, but an IS lens in that length will break the bank, I fear....