OK, so thanks to the advise of all of you i decided to go and get a70-200L f/4 IS for my zoom as a kit to my 40D. I have 17-85 IS and will be also getting 50mm some time soon.


Dumb question: I am very new to SLR and to photography in general, and I do not know how would I be able to tell if the lens I purchase is good...


If I only "play" with my camera at this time, very slowly learning, what would be the best way to test this lens to make sure it is not defective in any way?


Do you think I should wait until I get better with my skills...which may not happen until next century[:'(]


Or should I just go for it knowing this kind of lens is generally good and reliable?


Or is there an easy way to tell there is something wrong with it?


Any help will be greatly appreciated. Thanks in advance and I apologize if this is too dumb for this forum[:$] I have nowhere else to go...