hmm which lense????

Totally agree with Jojo, if you don't need the versatility of a zoom then the EF400 is most likely the way to go. I think the IQ and AF speed of the 400 is even better than the 500 f4 IMO.

As to which will take the better image, both can do well, but the 400 is certainly more able to take a better image, the rest is upto you.

I'm not totally sure about the price difference... I think it's quite a bit, but I would definately look into the 100-400mm f4-5.6 L IS. The IS will be a lifesaver when shooting handheld, especially if it isn't really bright when you are shooting. The IS won't freeze motion as the light goes down, but when you are at 400mm, and the fastest shutter you can get is 1/100 second or so, you will get a lot more keepers with IS than without.

It might not be the ideal lens for your situation, but it is definately worth considering. I haven't heard much bad about it.

alright thanks guys you really helped me out with my decision...

Brandon

get the new Zeiss 1700 and furget about it.