Well I recently attended the first Equestrian event this year since the lifting of Equestrian Influenza in Australia.
It has brought the entire Equine industry to a standstill literally.
It has a harsh day out to shoot .... as it was partly cloudy and sunny and cloudy again.
I had a go with my K10D and FA J 75-300mm lens (the elcheapo crap Pentax zoom).
It's not really suited to action and movement ... although the overly bright day did aid this lens a bit. I don't have a CPL for this lens (would have been a bit nicer if i had one).
Anyway ... my first time shooting equestrian ... so it was good fun learning.
Here's the lot that I found were the better ones.