Originally posted by jpzk Sure it does!
I used to own a Sigma 100-300/4 and it performed extremely well with the K20D!
I now have a "prime" DA*300/4 (smaller, lighter) which I use with TC's from time to time,
and it compares very well to the Sigma,
Either of these have great TC's you can add to the lens too, although the Pentax TC's are hard to come by these days.
No doubt both of them lenses would do the trick with a K7 or K5, with or without a TC.
JP
Why did you sell you're Sigma 100-300/4
just because of the weight
So that's just my point , if i decide not to go for this lens it will be only because of it's size and weight and then i could choose between both Pentax , 300/4 & 60-250/4.
Knowing what it's mainly for ( motorbikers on circuit ) why would the 300/4 be better then the versatile 60-250/4
The 300/4 : 1.07kg and 184mm long
The 60-250/4 : 1.230kg and 167mm long
Tests say the 60-250/4 is excellent and as good if not better then prime lenses at all focals , sharp wide open .
What makes me doubt is no one has this lens , it doesn't sell and you hardly read anything on any forums about it's great performance.
On the other end there are plenty of 300/4 owners and plenty of great comments everywhere , for many this is the ultimate Pentax long range tele