Canon or Sigma tele converter

For anyone who has experience with both Canon and Sigma 1.4x tele converter.

I've got a 5D body and a Sigma 70-200 f2.8 and I'm looking at both the canon and sigma converters. Just wondering what one would be more compatible with this combination yielding the best IQ.

Thanks you for your time.

Just curious; have you researched this one? http://www.bhphotovide​o.com …_4x_Teleplus_Pr​o_300.html

Before I bought mine it seemed like a few more people preferred it to the Canon.

I own the Sigma and have used the Canon. Honestly I couldn't tell any difference between the two regarding IQ.

The Canon has a protruding element so it wont fit on a wide range of its own lenses. The Sigmas element is flush so it DOES fit on a wide variety of Canon and other glass.

The Kenko that LV Moose linked to I think is newer and possibly better IQ. It can potentially work better with newer lenses.

On 1.6 crop I can't tell the difference between my sigma 1.4TC or my canon 1.4TC and the 2*TCs I can only tell apart when comparing them next to each other (as the sigma is infact a 1.95 rather than full 2*TC).

I've not had a chance to use either on fullframe but it appears that the sigma will give you a bit of vignetting when used on a fullframe sensor - in comparison to the canon - from this review/comparison here:
http://www.juzaphoto.c​om …_sigma_teleconv​erters.htm

I've got the Kenko Pro 1.4X and I really like it. Best part of the Kenko over the Canon is that you can use it on lenses that you can't with the Canon TC.

Many have reported that the Kenko ones will allow for faster AF then the Canon one. Hard to believe that a Canon TC will AF slower on a canon lens then a 3rd party TC on a canon lens, but many many tests and user reviews have confirmed this. I have only used the Canon 1.4TC briefly so I do not have real objective tests.

IQ seems to be very similar between Kenko & Canon. I do not have experience with Sigma TC's though.

Kenko PRO 1.4X on 200 f/2.8 @ f/4.5...

Thanks everyone for all your feed back.
I found out the the Canon 1.4x converter will not accommodate the Sigma 70-200 f2.8 lens.

Kenko Pro 1.4 for me. It does everything I want it to do and it does it very well.

I have no experience with the Canon or Sigma, as I bought the Kenko to start with and never saw a need to change.

get the kenko 1.4x TC... usable on all different brand lenses and doesn't degrade the image quality and only one stop loss.