Is 2x III extender sharper than the II version.

Thinking about getting the 2x III to use on my 70-200 2.8 and 300f4, can anyone tell me from personal experience if it's any sharper than the previous version? Thanks!!

Yes it is but I can't speak for the lenses you have listed. I have used mine on my 70-200 f 2.8 Mk II and on my 300mm f 2.8 and get excellent results, better than the previous version 2X. Keep in mind that if you use the 2X on your 300mm f4 you will wind up with an f8 lens and it will not AF on your 5d II.

According to SLRgear.com it is only sharper at the edges and in the corners. A German test confirmed that too (Traumflieger). The III version however has way better CA control.

Yes, there are a couple of tests on the net I've seen that go into great detail on this TC.
Here's a couple I had bookmarked

http://www.the-digital-picture.com …der-EF-2x-III-Review.aspx

and another

http://www.traumfliege​r.de …/telekonverter_​canon3.php

these are the two best I've found.

Larry Weinman wrote in post #13574126
Yes it is but I can't speak for the lenses you have listed. I have used mine on my 70-200 f 2.8 Mk II and on my 300mm f 2.8 and get excellent results, better than the previous version 2X. Keep in mind that if you use the 2X on your 300mm f4 you will wind up with an f8 lens and it will not AF on your 5d II.

Thanks for the info! Do you know if the 300 will AF on my 7d?

the f/2.8 version would, but not the f/4 version.

rockygarcia wrote in post #13575135
Thanks for the info! Do you know if the 300 will AF on my 7d?

so a 50 1.4 with an extender gives me a 100 f2.8 huh? never thought of that...

orena wrote in post #13575322
so a 50 1.4 with an extender gives me a 100 f2.8 huh? never thought of that...

Ya, but you're going to amplify any IQ issues the 50 1.4 has.

After getting my 70-200 f/2.8 II, I also wanted a set of extenders. And even though the digital picture review sighted above mentioned:

I could not justify the price difference. The primary advantage (IMHO) of the IIIs over the IIs, and I suspect the more significant reason for the large price difference, is the improved AF when paired with the new 'Super' telephotos. Also from that same review:

I recall from the press release when the IIIs were announced, that AF capabilities of the IIIs when paired with a lens that was not on that list (i.e., that predated that list) would be identical to that of the IIs.

Since none of those lenses will be finding their way into my kit anytime soon, I have a set of the IIs.

Per Canon, the "improved AF precision" of the Mark III teleconverters is accomplished by slowing down AF by about 25%.

With any 2X on 300/4, the lens becomes an effective 600mm f8 and will not auto focus on either 7D or 5DII.

The shortest lens you can fit any of the Canon teleconverters to is the 135/2. The Canon TCs have a protruding front element and physically cannot be mounted to shorter focal lengths. Won't work on the 50/1.4.

The 2X III seems particularly well matched to the 70-200/2.8 IS Mark II. I wouldn't expect it to work as well with the original 70-200/2.8, but the 1.4X II does (and I suspect the Mark III would, too).

Has anyone actually tried to AF on either of those bodies? I've managed to get my camera to AF at f/11 (stacked converters), even though it's not supposed to AF at anything slower than f/8...just saying

amfoto1 wrote in post #13577110
With any 2X on 300/4, the lens becomes an effective 600mm f8 and will not auto focus on either 7D or 5DII.

The 2X III seems particularly well matched to the 70-200/2.8 IS Mark II.

Thank you amfoto1, That was very helpful!!

Yes it is sharper and has been giving me great results on my 70-200 2.8 II. IMO it is giving me sharper images than my Canon 100-400 and the reason why I bought it.
It is great paired with the 70-200 2.8 II and i would recommend it to someone looking for more reach without loosing too much sharpness.

amfoto1 wrote in post #13577110
Per Canon, the "improved AF precision" of the Mark III teleconverters is accomplished by slowing down AF by about 25%.

This is not as big a deal as you might expect, especially with longer lenses and farther focus distances where the focus group has less distance to travel compared with shorter lenses.

Wrong - it fits various TS-E lenses just fine, including the TS-E 17mm and the TS-E 90mm f/2.8 (though sharpness with the 90mm seemed lacking, with the 2X Mark III).

It'll be interesting to compare the performance of the TS-E 17mm with 2X III TC to the TS 35mm f/2.8 S.S.C. adapted to EF mount.

Edwin Herdman wrote in post #13577816
Wrong - it fits various TS-E lenses just fine, including the TS-E 17mm and the TS-E 90mm f/2.8 (though sharpness with the 90mm seemed lacking, with the 2X Mark III).

And the MP-E65

Bob