Help: Bought Sigma 28-70mm f2.8. XSI Compatibility?

Hello there,
I was hoping to get some people to help me figure out the issue with this lens. I bought this lens from a member on this forum. at the time they had no information on this lens they could provide but they assured me it would work great no matter. When i received the lens it wouldnt work on anything but wide open f2.8. anything else says contact error and it freezes my camera. I thought it was an incompatibility problem and i took it to b&h for advice. the guy there told me the lens was new enough not to need rechipping and it was probably defective. the lens cap says 'for canon af' and the red/white dots are for ff and aps-c compatibility correct.

are any of you familiar with this lens? i am posting pictures because i cannot find any info at all on the web. have anyone used this lens. I am just trying to single the cause of the problem to see if i have the right to escalate the claim on paypal as my initial refund request was denied.

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Older SIgma lenses (before EX) will only work wide open and you'll get an error message if you try any other aperture. No solution. Sigma is not re-chipping lenses anymore. Return it.

Have you tried cleaning the contacts on the lens and camera?

You can email Sigma the serial number of the lens and they should be able to tell you if it is compatible or not.

gasrocks wrote in post #6957153
Older SIgma lenses (before EX) will only work wide open and you'll get an error message if you try any other aperture. No solution. Sigma is not re-chipping lenses anymore. Return it.

see thats the problem. the seller said it worked on his 1d, xt, and xti so i see no reason why it wouldnt work on xsi unless i was dooped.

DDCSD wrote in post #6957171
Have you tried cleaning the contacts on the lens and camera?

You can email Sigma the serial number of the lens and they should be able to tell you if it is compatible or not.

i havent tried cleaning the contacts, my xsi is only 1 month old and my 2 other lenses work perfectly fine. i am waiting till tomorrow to call sigma. holidays messed up all hours.

Been there, done that. I bought a Sigma that did not work on my body from a seller who said it worked on his. Trouble was he never tried it on any other aperture than wide open.

Is it possible that Canon has "updated" something on the XSi that makes it different from the older models? If so, perhaps the seller was being honest but never used the lens on a newer body. Do you have access to an XTi or the like to test this theory?

It won't necessarily solve your problem but it could give credence to the seller.