Sigma 17-35 chip

[russellsnr2]

Hi, I have seen on some forums that if you have a Sigma lens (in my case the 17-35 EX) that they need to have a chip inserted to make them compatable with digital camera's. Can anyone please tell briefly what differance the chip makes to the lens.

[Gordon S.]

I've got a Sigma 28-70 that when put on my 350D AFs fine but when you take a shot the camera reads 'Err 99'. Its something about the communication between the body and the lens about the aparture that Sigma didn't write into their programming. They simply need to correct that in the lens and all is good.

[Andy_T]

Some older sigma lenses might not be compatible to Canon's newer cameras (because Canon changes the protocols now and then and only pays attention to staying compatible with Canon lenses).

If this is the case, you can send the lens to Sigma, and they will change the chip in the camera with a different one that is compatible with the new protocol. You can't get a chip anywhere to insert into your lens yourself.

Bear in mind that there are some lenses were Sigma states that 'there are no more chips available' ... so they can't be made compatible with new Canon cameras.

Sigma will be able to tell you in detail.

Best regards,
Andy

[Jon]

It's not just for digital cameras. Any EF lens has some chips inside, for AF, aperture control and such. The issue with Sigmas is that Canon never released the spec, so Sigma had to reverse-engineer what the lens should be doing and design their own chips. They didn't get it right on the earlier lenses, and as Canon bodies started making fuller use of the connections Sigma lenses started to ffail on the Canon bodies. So Sigma had to develop replacement chips for the lenses to be usable on the new bodies. If you have an older Sigma, and if Sigma released an upgraded chip, and if they still have some of that chip in stock, they can upgrade the lens chip to allow your older Sigma to work on your newer Canon.

[raylks]

The Sigma lens you found on sale as new in the market are compatible with the EOS bodies. No worried.

[russellsnr2]

Hi, Thanks for replies I have Emailed Sigma UK and they will replace the chip within a service on the lens.

:D :lol: :) :D

[mcaldwell]

I have a 20D due to arrive on Tuesday. I have a Sigma 28-200 /3.5 that was used on my wife's Canon EOS camera. I tried it down at the local Ritz and got the famous Err 99. I only recently found postings about a chip swap. I can't find the Sigma home page to inquire. Would love to get this lens upgraded. Someone please provide a link??

BTW: when the chip is swapped, will the lens still work in my wife's film 35mm SLR?


Mike