I'm thinking about buying a 2x extender to go with my 70-200mm L. Before I do that I want to test one to see if the autofocus works, and to compare the quality with my sigma 135-400 DG, which it'll be replacing if it's any good.
I've found one company here http://www.hirental.co.uk/lens_hire/...on_lenses.html but I've really got no experience doing this.
Any advice on that company or renting in general much appreciated.