Lens for dog agility / action

[DavidEccleston]

Well, the 70-300mm f/4-5.6L IS USM is ordered. The sale at Aden ends today, and it would jump by $350 after taxes if I waited any longer.

The 70-200mm f/4L IS USM vs the 70-300mm isn't an easy choice. The "it's f/5.6 at the long end" argument is mostly silly, since it's only f/5.6 well past 200mm. The major valid argument is that it's 2/3 of a stop slower as you near 200mm. But something clicked earlier today. I imagined all the 70-200mm owners saying "But I take 80% of my shots at 200mm!". So I should opt for the faster aperture at 200mm, right? What clicked was that pushing against 200mm all the time means that all these people really wished their lens went PAST 200mm.

Thanks to everyone who replied. I'll be sure to post some pics when the new glass arrives.

[Sheiky]

What clicked was that pushing against 200mm all the time means that all these people really wished their lens went PAST 200mm.

Great reasoning! I hope you like the new lens, but I'm pretty sure you will. I'll be tuned in for the first results
I hope you won't make too much shots at 300mm though...you might want to switch to the 100-400