Are there known issues with Sigma Lenses & 20Ds??

Since getting our Sigma 24-70 F2.8 a week ago - our 20D keeps freezing periodically. It doesnt come up with errors.. just goes blank or freezes and the only way you can fix it is by taking the battery out...

It never used to do this at all and we've had the camera 6 months now... admittedly it wasn't brand new when purchased but we've had no other issues....

Can't say that I've heard of any major problems with this lens.

Not the same lens, but I regularly use a Sigma 70-200 f/2.8 and have had no problems I can remember with it. I also had the 17-35, again no problems (apart from the fact that it was a cr*p lens!)

Some older Sigma's need re-chipping to make them work, but this doesn't sound like your problem.

It's not a lens with systemic problems; maybe you just got one that needs service. Have you got access to another Eos you can try it on? May want to exchange it while it's still new; wait too long and you'll have to send it back to Sigma for service.

I believe there were problems with some early 24-70's that needed a new 'flex board' or something top be fully stable with the 20\d's but don't take my woprd for it as it it hazy memory ... PM Lightrules AKA JoJo as he will know the situation ... and if I am wrong apologies. If it is a new lens it should be fine BTW. You could also try cleaning the contacts carefully.

Could be another example of the issues that sometimes arise with 'reverse engineering'.

I have 4 Sigma lenses that I use with my 20D, no problems whatsoever.

Try thougherly cleaning the contacts on the lens and body, may just be a communication issue

The early firmware in the 20D sometimes caused that problem. Make sure you have the laest firmware.
http://www.canon.co.jp …0d/eos20d_firmw​are-e.html

I use quite a few Sigma lenses without a problem on both my 20D and 5D.