Merci Hélios.

"observation des divergences de qualité d'un objectif à un autre" :

Canon EF 70-200mm f/4 USM L - Photozone Test Report / Review
"Verdict

The Canon EF 70-200mm f/4 USM L is a very harmonic package combining exceptional build quality with an excellent and very even optical performance throughout the range. Adding an EF 1.4x II only results is a slight loss of quality which is remarkable for such a slow speed zoom. And even better the price tag of this lens is amazingly low for what it offers ... or to be precise: what it can offer. Unfortunately the quality of the two tested samples varied quite a bit which is a little disappointing especially regarding the L designation. So if you can get a good one the EF 70-200mm f/4 USM L can be highly recommeded! "

En lisant entre les lignes de ton post, j'en conclue que tu as une préférence pour le 70-200 F4 USM ? :angel_not