So I returned my 7D which had issues and decided instead to get some decent glass. While not a monetary decision, a used Canon 17-55mm f2.8 IS from B&H was certainly easier on the pocketbook. I took this with my XTi (400D) last weekend. I set the ISO at 400 and used the P mode. This put the shot at 1/160s with an aperture of f/4.5. My youngest, in the middle, was a puddle of tears last year riding this "miny" kid-sized roller coaster. But my other 2 children convinced him to not cry, rather say "Weeee!"
Here is another shot. This has been cropped:
Both shots were reduced in file size and sharpened in Photoshop.
Mark
Here is another shot. This has been cropped:
Both shots were reduced in file size and sharpened in Photoshop.
Mark