Extending a lenses focal length by a factor of 1.4x, Extender EF 1.4X III incorporates phenomenal optical performance with minimal chromatic aberration and is a perfect complement to many of Canon super telephoto lenses.
It features a built-in microcomputer for seamless communication among camera body, lens and extender; features careful lens placement and coatings to minimize ghosting and flare and even has a new Fluorine coating that keeps soiling, smears and fingerprints to a minimum.
An integral part of many professional systems, Extender EF 1.4X III maintains high standards not only optically, but also in terms of rugged, dustproof and water resistant construction.
This lens is only compatible with fixed focal length L-series lenses 135mm and over, as well as the EF 70-200/2.8L, EF 70-200/2.8L IS, EF 70-200/4L, and EF 100-400/4.5-5.6L
Excellent - used with 100-400 and 200-400 Canon lenses. Sharp as a tack with the lenses and autofocus works well
I didn't have a lot of high hope but I wanted a tad more reach at times with a 300mm f2.8. Not only does this do the job , image quality does very well. Over all I am very happy.
Since moving up to a full frame camera from a cropped sensor, I miss the extra reach that the cropped frame gives to the lenses. This tele extender almost gets it all back - (1.6 vs 1.4) without a sacrifice to clarity and with only one f stop difference.
The 1.4x II version is a very good one, but this one makes for noticeably faster autofocus.
I use this with my 100-400 IS II lens and my 400 F4 DO lens. works well and is reasonably sharp, especially with the F4 lens. They charge too much for this product. It is way overpriced.
excellent combination with the 300 f2.8L
Very happy with the extender. Use it on my 300 L f4 with my 7D.
When I upgraded to a full frame sensor I missed the additional magnification. I had played with a 2.0 II extender, but found the IQ loss just too much. This pairs very well with a 5DMKIII and a 20-200 f2.8 LII IS lens. Obviously, not as tack sharp as the lens on its own, but a great compliment to get the extra 80mm of tele.
I hated my old 2x extender but still needed more reach on my 70-200 and couldn't afford the 300mm 2.8 lens yet. I read some other reviews and this 1.4 seemed pretty popular. Turns out, it's pretty darn good. The improvement over the 2x is stunning. The slow focus and softness are reduced to usable levels. I use this mostly for college football games and can still get good focus with fast action and the softness, which is noticeable still, is acceptable in the world of fast action. I would hesitate to use this for still life or portraits though.
added to my Canon EF 300mm gives the additional magnification I was looking for in photographing wild life...loss of speed (reduced to 5.4) has not been a problem except in the early morning and late evening...compensated by adjustment in ISO...would recommend for wildlife shooting