The Canon EF 2x II Extender is an easy and very affordable way to dramatically extend the reach (focal length) of compatible Canon L Series lenses (and a few additional lenses). This review will sound very similar to the Canon 1.4x Extender Review, but the 2x function is basically the same.
The lens is the EF 100-400 L IS. Without the extender the autofocus options in the Q menu are all operational. When the extender is fitted it only shows a green box MF. Pressing the set button twice turns the box blue but still shows MF. (I'm trying to give as much info here as possible)
Teleconverter 2.0X (Doubler) Extender for Canon EOS & Rebel Series (EF & EF-S Lenses) Black T4i T5 T5i T6 T6i T6s T7 T7i 4000D 6D 7D 60D 70D 77D 80D 5D II/III/IV
I'm using the 100-400L USM IS II, the Extender 1.4X III, and the EF-RF Control Ring Adapter on my R5, which gives an equivalent 140-560mm zoom range. Of course the added lengths of the extender and adapter add to the overall length, but it's definitely a usable combination. D&F AF Auto Focus Macro Extension Tube Set EOS EF/EF-S Lens Close-ups for Canon EOS EF Lens Such as Canon 7D,500D,600D,700D,5D Mark II III, Rebel T2i, T3i, T5i. 77. 50+ bought in past month. $2099. FREE delivery Fri, Jan 12 on $35 of items shipped by Amazon. Overall Pick. . 108 477 48 236 353 170 166 150

canon extender ef 25 ii