First post,

hello I am new to this forum and i'd to have some shares about the extender of 1.4x, at the store they offered me 1.4x II and 1.4x III, can somebody give me info the quality to the result of the II and III, as the II is more expensive than III. in this case i need quality not only the updated one.
and the second question is, if I paired the 70-200 f/2.8 USM with extender 2x at the longest focal 400, does the quality is sharp? or do I need to spend another 100-400 f/4.5-5.6L IS USM at focal of 400 ?

Grazie..