Différence de qualité entre deux mêmes objectifs

[Air23]

Je ne serais pas surpris que les série L soit conçu avec ces principe!

En tout cas, ils échappent pas au phénomène.

Un exemple parmi d'autres, la conclusion de Photozone à propos du 70-200 4 L :

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 recommended!