Sigma 2x v Canon 2x

[chris954]

I currently own the Sigma 2x EX DG APO TC and would like to know if anybody has any experience of this compared to the Canon EF 2x MK i or MKii, specifically image quality, auto focus accuracy etc. I'm a bit disapointed with the success rate I'm getting with the Sigma attached to my 120-300 f2.8 and 1d MKiii and was thinking about trying a Canon to see if the results are any better. I've tried all the usual adjustments, micro adjust focus etc, I've had the camera on a tripod with shutter release and mirror lock up but still getting soft out of focus images.

 

[artyman]

I have my original Sigma 2X that I bought with my 150-500, I also acquired a Canon 2X Mk1 when I got my Sigma 120-300 f2.8, I couldn't perceive any difference in IQ between the two, as regards focusing I've not had any problems.

 

[pooley]

Save your money.
The mk1 is poor
The mk2 is reasonable but probably along the lines of your sigma
The mk3 is a lot sharper and has excellent IQ but the only time it will improve your af is when attached to a canon series 2 supertele or mk2 L zoom where the built in chips can talk to each other.

Mike