I shoot with a Nikon D300 and have enjoyed the Nikon 18-200's flexibility for my daughter's softball photos (here's a link to photos from her team's http://www.pbase.com/donutrun/smcfallball09 Fall '09 exhibition games ). Now, as she prepares for her senior season of college softball, I'm mulling a lens with a bit more reach (she patrols centerfield) ... something like the Sigma 50-500 ...

I'm thinking of renting one for their opening season Florida swing in mid-March to try it ... Anyone ever used "the Bigma"? Speed/accuracy of the autofocus? Image quality? I'm not to worried about size/weight as I shoot from a monopod nearly exclusively during softball. There's also a Sigma 170-500 or 150-500 that I see floating around on ebay ... Or the Nikon 80-400, though I've heard the speed of it's autofocus disparaged ... Then I see 400s or 500s offered by Tamron or Tonika and I'm not sur what to make of them ...

Thoughts?

The 170-500 seems more logical for the reach you want. I'd look more at each lense's F stops and go for the one w/ the largest apperture, that is an F2.0 vs F2.8.

i was considering a sigma at that focal length but ended up going with the canon 100-400

I will try to find some of the stuff on the bigma....from what i remember there were some that really liked it and others that didnt

also one of those has OS(their version of image stabilization) but cant remember which it is

i thought the 15-500 with the OS and HSM was the one to look at but you might want to take a look at this.... http://forum.warehouseexpress.com/message.asp?FTopicID=4922