Originally posted by filorp i dont dig such a explanation... consumer zoom faster than professional lens? Tell something like this to canikonians... 16-85 faster than 70-200vr2 because 16-85 is plasticky lightweit and wobbly.... you'll hear the laugh(if it was a true... fact is 70-200vr2 heavy and bulky is the fastest lens iv ever checked)!!!
can laugh how long you want.
pentax is using different drives and uses in the old *line the way of the long focusway.
the construction is absolut different.
canon 18-55 usm is also much faster than the 2,8 400 usm
and in real focusareas the 17-70 is not realy faster,only the complete drive from close to endless is much faster,because has a shorte way to drive.
sure,the 50-135 is not the fastest,but fast enough for most action i capture.
next lens generations on new cameras are much faster