I bought the 2.0 Version III extender to add utility to my 500mm f/4 L. I wasnt interested in doubling my 70-200mm as I already have a 100-400mm. My interests were: doubling the focal length of the 500mm f/4 for use on a 7D Mark 2 body to get maximum reach for long range shots, and on a 5D Mark 3...

This is the second Canon 2x extender I've had. I use this with a full frame Canon 5D Mark III and find it remarkable for getting closeups of people in day-to-day activities, sports, and closeups of flowers and of wildlife (e.g., elk and bison in Yellowstone National Park).

Consistent Output; Durable; Fast / accurate auto-focus; Nice Bokeh; Rugged; Strong Construction

Heavy

The 2x converter is excellent when you need some extra reach. I use with the 70-200mm 2.8 when I need extra reach, but still need the shorter minimum...

Excellent image quality

nothing

This is a superb extender which works flawlessly with the Canon prime telephoto and super telephoto lenses. I bought it to supplement my Canon 300 mm f/2.8 IS II lens to give me an effective 600 mm f/5.6.

Very cost effective way of increasing your telephoto reach; It's very light and compact

Loss of two stops of light compared with the mated lens

I photograph minor league baseball and this allows closeups of the outfield or field shots from the upper level coupled to my 70-200 L series lens. I am not a professional and use of this lens allows great reproduction for families, players and fans.

High Quality; Well Made

Heavy

good add on for F2.8 lens. Focusing is slow but end result is sharp. I am using on my Ef200mm f2.8 lens.

Durable; Easy To Use; Reliable

Bulky

Outstanding images with this in conjunction with my 300mmF2.8L. Frustrating that it does not work with the 100-400 F4.5L ll USM, while it did work with the original version of this lens, (although this was not consistent). I also own the 1.4x extender.

Very.co.uk said delivery would be about 6 weeks, but this arrived within a week, so very impressed by this. I attach this to my 70-200mm f2.8 is 2 lens to get 400mm and the quality surpasses expectations, considering I would have to pay two grand for a 400mm lens outright.

I haven't used this much to speak of, but after seeing this review, I thought I would give it another try. The examples are close with the Extender. I like it and definitely need to use it more to see if I can use better settings. Also I use it on my 80D camera.

ok I've given this a few tries now. I know that you can't use this extender with the aperture wide open. Despite trying various settings I've found getting a clear image from it very difficult, you need to up the aperture to have half a chance, which results in having to up the iso even on the...