I suggested the 50mm f1.8 lens to you because it was a good lens for INSIDE, that would do better in low light situations than the 18-200mm lens.
When I use the 50mm to shoot my dog, I am in my fenced in yard.
This was shot on a cloudy day, in mainly the shade (we have two trees in our backyard that really shade it).
I don't remember what my aperture was set at (I believe it was f2.2 or f2.5), and I *think* my shutter was 1/800 or a tad higher).
Some more from the sunshine shooting I did (the other pics from the other thread):
All shots taken with the D300 and 50mm f1.8
She was in non-stop motion, so all are completely frozen.
Again, I don't like shooting ANYTHING in direct sunlight like that, but I didn't have a choice, really. And they didn't come out too bad considering.
One of the problems with using the 50mm f1.8 for shots like this (regarding the FPS and just in general using it for action shots with dogs) is: Obviously, you have to be closer to get a good, sharp shot. But, due to that fact, you'll often cut off parts of the dog in your photos. Taking that into consideration, unless you're a coordinated saint and are perfect, the FPS isn't going to be THAT much of a use because as the dog moves, you're going to cut off parts of it. My shots from that sunshine shooting came out GREAT...if you don't worry about the fact that I cut off paws and even most her legs in a lot of the shots.