Could you please tell me a little more about the 70-300L being optimized for crop bodies? That's a lens I find interesting and I might even consider it... Thanks!I'm not sure that Canon technicians said the 70-300L was optimized for crop bodies.11
Sorry, I am not able to dig up the link just now - but it wasn't the one neuroanatomist mentioned. And I don't remember if it was a Canon *tech*, might have been a marketing guy or something. But the gist of the article was:
Canon designed the 70-300L because of user requests for a quality but affordable, up to 300mmm, physically shorter, less heavy traveling lens than the older 70-200s or fixed primes. And people with these requirements often use crop bodies.
Most important: On full frame, the 70-300L is said to become a little less sharp wide open. If Canon had really wanted it, they could have put in a little more or better glass for a higher price - but they didn't, because you won't notice this on aps-c due to the crop factor. And this at least somewhat fixes the main craziness of using a ef L lens on aps-c: You are buying top quality glass, carry the weight and don't even use part of it!
You can find a lot more information about the 70-300L in the recent 70-200 and 70-300 threads. For me, the size-weight-iq-af-zoomfactor-buildquality-price combination and tradeoff is just right. So I'm really "canon rumors-infected" now: I recommend my own gear :-p