[jho]

I have the option of getting two second hand lenses for the same price. Either a Canon 70-200 f2.8 L with 1.4 extender(non IS) or the Canon 70-200 f4 L IS with the same extender. I am having a very hard time choosing between them. My use for them would be indoor sports (in some not so well lit conditions as well as some well lit ones) and outdoor sports, some wildlife photography (mostly birds and small mammals like foxes and mink) and of course general photography, like portraits and landscape. I have the Canon 60d. The reviews I have read are conflicting in as much which is better, having the extra stop in aperture in the 2.8 or the extra stops in IS in the f4 IS.



Also if the image quality of the 2.8 will degrade considerably if using the 2x extender.



I do have the Canon 70-300 4-5.6 IS USM (non L) and find it has a hard time tracking fast objects like flying birds and I have a hard time focusing on smaller objects if they are moving towards or away from me). I assume both of the above lenses are better at tracking movement. (exactly what Brightcolours warned me about a few months back). The 70-300 is quite sharp if the subjects would just stay still so flying birds are quite a pain.



Can anyone help me choose?

I should state I have the Sigma 17-50 2.8 OS and the Canon ef 85 1.8. as well. Both of those are simply marvellous.



best regards

[Brightcolours]

The f2. is the better one for indoor sports for two reasons: You get a stop more light so you can keep the exposure times short when needed, and you get more subject separation from the probably distracting background.

IS is of little value at these focal lengths for sports.



For wild life, both should be kinda equal... the f4 IS having a plus when light is lower. The f4 of course is much lighter (about half the weight, and similar to your 70-300).



Both will do well with tracking moving subjects. Activating all AF points can help, depending on the subject.