I'm learning a lot on this forum. As a result of all your good advice, I now have my new everyday lens - a Tamron 28-75 f/2.8 - and am delighted with it. It's the perfect range for the kind of photography I do, and I love its speed and IQ. For dog sports, I've tried both the 55-250 and the 70-300, and while I like them for other types of photography, I realize they may not cut it in the long run for this type of high-speed action shot because the focus isn't quite quick enough. I'm losing shots because of OOF. I'm going to practise through the summer to see if my keeper rate improves, but expect eventually to trade the 70-300 for a 70-200 f/4 - with some reluctance, because the 70-300 is a great lens for other things, and I like the range. However, I love my 55-250 for backyard wildlife, portraits, etc., and will keep it even after I get the sports lens, just because it's so light and convenient. So thanks again, guys, for setting me on the right track!
And after all this, I'll be after a 85 f/1.8 for indoor dog sports and a 60 macro. It really is endless, isn't it? I'm going to have to take a second job to pay for it all ...
