Fantastic replacement to an expensive lens but the lens is expensive for a good reason. In almost every camera, the auto focus stops working with the 2xiii. So unless your eyesight is 6/6 unlike mine, chances are that not every shot you take will be sharp. With a loss of a couple of f stops too.

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

Very good to keep in the bag and great for turning a 300 f2.8 into a 600 f5.6 but with limitations. If you don't need to crop then its fine. If Canon made a 1.7x I would have bought that, knowing how good the 1.4x is. Overall pretty good but if you want long lens quality, buy the ￡￡￡￡￡ lenses.

Durable; Lightweight

Looses Some Image Quality

I really enjoy shooting with this attached to my f2.8 80-200 lens. The only sadness is that it is limited to f 5.6. This is not a problem in the sun or other bright circumstances but is a problem with low light - especially when hand holding the shot

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

As represented above, Canon offers a huge range of prime (fixed focal length) lenses. Options range from ultra-wide angle through super telephoto and from tilt-shift through macro. There is a lens for practically every need included here.

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

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

Tested on 5D MkII and 70-200 Mk II Do your research, you are going to lose autofocus speed, a little bit of image quality (depending on what you pair it with). Saying that I was comfortable with the images coming out, I had the benefit of not having to shell out for a 300mm or 100-400mm and carry...

When I first tested this against the Mk2 extender for IQ with static indoor test subjects, I thought I had made a mistake in spending so much in that the differences in IQ other than in the mid / corners did not seem that different.

Cost effective solution as works superbly with my 70-200 2.8 Mk11; much better contrast / saturation and tighter fit than Mk11 version

Images are slightly degraded and will always be compared to equivalent length alternative lenses