Canon Extenders

I have been reading reviews and posts about the Canon Mk III 1.4x and 2x extenders. As a new DSLR user, I think I understand the basic advantages and disadvantages of these bits of kit. If I bought one, it would be mainly for wildlife shots. Which would be the better buy if I was only going for one of them? Thanks in advance for any advice forum members can give me.

What lens and camera body do you plan to use?

An extender always degrades image quality, and a 2.0 more than a 1.4 extender. What lens do you want to use it on?

I would use it on a 7D with my 70-200 MkII f/2.8 lens

Well, the 2x works great with the 70-200 II, but of course the IQ and AF speed with the 1.4 will be better. It all depends on how much reach you really need. If you need the 400mm, get the 2x, if you don't, the 1.4x. Or maybe both or the one you use the most, you get the Canon III and for the other a cheaper, 3rd party option. I have the Kenko Pro 300 1.4 DG, cheap and it performs well.

freddyronny wrote in post #15178080
Well, the 2x works great with the 70-200 II, but of course the IQ and AF speed with the 1.4 will be better. It all depends on how much reach you really need. If you need the 400mm, get the 2x, if you don't, the 1.4x. Or maybe both or the one you use the most, you get the Canon III and for the other a cheaper, 3rd party option. I have the Kenko Pro 300 1.4 DG, cheap and it performs well.

Great advice! Thanks so much. I'll have a look at the Kenko.

Chris Hall wrote in post #15178147
Great advice! Thanks so much. I'll have a look at the Kenko.

Please note that I have the Kenko on the Sigma 120-300 f/2.8 OS, but I'm sure it'll work just fine on the 70-200 as well. I only payed 125 euro for it, so not a bad deal

With wildlife, you often need as long a lens as you can get... so with the 70-200/2.8 Mk II I'd lean toward a 2X teleconverter. 200mm is pretty short for wildlife and 280mm (200mm + 1.4X) isn't a whole lot better. That's especially true if using the lens on a full frame camera. The "free 1.6X teleconverter effect" of crop cameras (7D, 60D, etc.) helps, too.

If considering a 2X, then I'd most likely stick with the Canon 2X Mark III. I don't know that any other brand will work nearly as well on the 70-200 Mark II (I would't even use my 70-200 Mark I with 2X Mark II, there was just too much loss of image quality).

If you go with 1.4X instead, then the Kenko Pro 300 DGX is a strong possibility. By all reports, it's virtually as good as the Canon (Mark II or Mark III, both are pretty good). And a 1.4X leaves your viewfinder brighter, the AF faster and has less negative effect on image quality than a stronger teleconverter. The Kenko DGX might or might not maintain the same level of AF speed as the Canon... I dunno, haven't tried it. The earlier Kenko "DG" is slower than the current "DGX" version... upgrades to AF performance were one of the key features of the new model. For use on a zoom, I wouldn't consider the cheaper Kenko 1.4X MC4 teleconverter. And definitely not the 2X MC4.

The Kenko teleconverters might have one advantage over the Canon... all the Canon Mark II and Mark III have protruding front elements that fit inside the rear of the lens. The Kenko TCs don't. This limits to an extent what lenses the Canon can be fitted to, Canon says the 135/2L is the shortest and the 70-200s are the only zooms, tho there are some work arounds and some make them work on other lenses. The Kenko have less limitation in this respect, but in general a teleconverter works better with a prime lens, than it does with a more optically complex zoom.

According to Canon, the two Mark III Canon TCs are actually designed to slow down AF a bit, for greater accuracy. This is probably offset by faster AF performance in the newer lenses, probably including the 70-200/2.8 Mk II.

From Chuck Westfall: As with previous EF Extenders, usage of Series III EF Extenders lowers AF drive speed to improve AF performance. When Extender EF 1.4X III is used, AF drive speed is reduced by 50%. When Extender EF 2X III is used, AF drive speed is reduced by 75%. This may seem like a drawback, but in reality subject tracking performance remains quite high when Series III Extenders are used with IS II lenses. This is due to improvements in AF precision made possible by the new microcomputer in the extenders. (See http://www.learn.usa.c​anon.com …ertelephoto_art​icle.shtml for more info about the extenders and various lenses.)

amfoto1 wrote in post #15178577
With wildlife, you often need as long a lens as you can get... so with the 70-200/2.8 Mk II I'd lean toward a 2X teleconverter. 200mm is pretty short for wildlife and 280mm (200mm + 1.4X) isn't a whole lot better. That's especially true if using the lens on a full frame camera. The "free 1.6X teleconverter effect" of crop cameras (7D, 60D, etc.) helps, too.

If considering a 2X, then I'd most likely stick with the Canon 2X Mark III. I don't know that any other brand will work nearly as well on the 70-200 Mark II (I would't even use my 70-200 Mark I with 2X Mark II, there was just too much loss of image quality).

If you go with 1.4X instead, then the Kenko Pro 300 DGX is a strong possibility. By all reports, it's virtually as good as the Canon (Mark II or Mark III, both are pretty good). And a 1.4X leaves your viewfinder brighter, the AF faster and has less negative effect on image quality than a stronger teleconverter. The Kenko DGX might or might not maintain the same level of AF speed as the Canon... I dunno, haven't tried it. The earlier Kenko "DG" is slower than the current "DGX" version... upgrades to AF performance were one of the key features of the new model. For use on a zoom, I wouldn't consider the cheaper Kenko 1.4X MC4 teleconverter. And definitely not the 2X MC4.

The Kenko teleconverters might have one advantage over the Canon... all the Canon Mark II and Mark III have protruding front elements that fit inside the rear of the lens. The Kenko TCs don't. This limits to an extent what lenses the Canon can be fitted to, Canon says the 135/2L is the shortest and the 70-200s are the only zooms, tho there are some work arounds and some make them work on other lenses. The Kenko have less limitation in this respect, but in general a teleconverter works better with a prime lens, than it does with a more optically complex zoom.

According to Canon, the two Mark III Canon TCs are actually designed to slow down AF a bit, for greater accuracy. This is probably offset by faster AF performance in the newer lenses, probably including the 70-200/2.8 Mk II.

From Chuck Westfall: As with previous EF Extenders, usage of Series III EF Extenders lowers AF drive speed to improve AF performance. When Extender EF 1.4X III is used, AF drive speed is reduced by 50%. When Extender EF 2X III is used, AF drive speed is reduced by 75%. This may seem like a drawback, but in reality subject tracking performance remains quite high when Series III Extenders are used with IS II lenses. This is due to improvements in AF precision made possible by the new microcomputer in the extenders. (See http://www.learn.usa.c​anon.com …ertelephoto_art​icle.shtml for more info about the extenders and various lenses.)

Thanks for posting such detailed advice. It's much appreciated!