p.1 #2 · Used 300mm f/2.8 IS I - what to look for?
Looks into the elements very carefully. Because of the big elements, stuff can get in easily- prevent yourself from sending it into CPS to get it cleaned. Also look carefully at the front element as there are UV filters for it!
p.1 #3 · Used 300mm f/2.8 IS I - what to look for?
I would say check the drop in filter to see if it's free of scratches, also check all the AF stop buttons and that the focus preset works as it should, if they give you a key for the case make sure it works, the tripod ring should turn smoothly and the hood should fit nice and tight with the lock knob.
