[LesMizzell]

Let me put this a different way ... the best lens so far for what I do is the Tamron 70-200 f2.8. However, it's a little too long on the short end, and a little too short on the long end. If somebody would make a 50-250mm 2.8 I'd be all over it, regardless of the cost.

However, there *is* a lens that is almost perfect in focal length - the Pentax SMCP-DA 60-250mm. Sadly, there's no way it would work on my K10D to shoot in the lighting situations I find myself in since it's only f4.

But, the K5 is so much improved with higher ISO numbers, that it seems the 60-250mm would almost be the SAME on the K5 as the Tamron is on the K10.

Or, am I crazy here? I'm not giving up my fast glass, but seems I could use lenses I couldn't think of using before once I switch to the K5.

[interested_observer]

Well the lenses that I do have would just perform that much better. No problems with the 31/1.8 and the 50/1.7, however Pentax has nothing really for the 12-24 - and they are not bringing out a 11-16/2.8 from Tokina. I do not do enough over 50 to warrant a replacement of the 55-300 with a 60-250. So, yes higher ISO capabilities of the K5 would certainly help.

However, what I am really interested in is the LOW ISO levels of the K5 - at 80 with the expanded dynamic range, that both sounds and looks very interesting. With a tripod, the lenses I have should work just fine....

[Urkeldaedalus]

Let me put this a different way ... the best lens so far for what I do is the Tamron 70-200 f2.8. However, it's a little too long on the short end, and a little too short on the long end. If somebody would make a 50-250mm 2.8 I'd be all over it, regardless of the cost.

However, there *is* a lens that is almost perfect in focal length - the Pentax SMCP-DA 60-250mm. Sadly, there's no way it would work on my K10D to shoot in the lighting situations I find myself in since it's only f4.

But, the K5 is so much improved with higher ISO numbers, that it seems the 60-250mm would almost be the SAME on the K5 as the Tamron is on the K10.

Or, am I crazy here? I'm not giving up my fast glass, but seems I could use lenses I couldn't think of using before once I switch to the K5.

Your thinking to me seems basically correct here. The K-5 allows you to take advantage of the DA*60-250's versatility in situations where you would have used the Tamron with your K10D, plus the K-5 has better autofocus so the DA*60-250 will actually work better on the whole.

However, I'd hesitate from saying that the DA*60-250 on the K-5 is the SAME as the Tamron 70-200 on a K10D. As I'm sure you know, there are reasons to shoot at f/2.8 don't just have to do with shutter speed.

[Wheatfield]

No. Slower lenses = zoom.
I try not to use them.