Rick De Smet , Feb 14, 2005; 03:13 p.m.
Greetings. I've just changed from my good old EOS 30 to the EOS
20D.I waited a long time to do this but I finally did and...Problems.
I have 2 lenzes, both Sigma , a APO 400mm 5.6 and an smaller 28-
105mm Aspherical. No problem I thouhgt until I connected them to my
20D. Power on, pushed the shutter and ... Error 99. Damn I tried the
400mm. No problems in the beginning until I changed the AV. When is
use the manual mode AV I dont have any problems when I shoot at
5.6 , when I change the Aperture to a higher value the Err 99 comes
on again. From the moment I click my 28-105 in the error already
comes on when I set the power on. This situation is very
onconfortable and I hope I continue using my good old Sigma's.
What should I do? Are there others with the same problems?
Please help.
Greetz Rick
Yaron Kidron , Feb 14, 2005; 03:23 p.m.
Send them to Sigma for an upgrade.
-- Yaron
Bob Atkins 
, Feb 14, 2005; 03:48 p.m.
There are lots of people with the same problem. Sigma lenses don't have a good compatibility record with newer EOS bodies. Some work, some don't.
If the lenses are currently in production, Sigma will usually rechip them to work the newer EOS bodes.
If the lenses are out of production you're out of luck. Your best bet then is to sell them and buy something that works with the EOS 20D.
Future incompatibility is one of the things to bear in mind when buying 3rd party lenses. Some companies seem to do better at this than other.
Kin Lau , Feb 14, 2005; 03:58 p.m.
I've spoken to Sigma before about this. The APO 400, is not upgradeable/rechippabled. The 28-105 maybe, but you'll have to call Sigma about it. If it can be done, it's usually done for free.
Carl Chandler , Feb 14, 2005; 04:17 p.m.
Hello Rick.
I have had the same problem, I updated to the new firmware 1.1.0 . Everything works fine now, also make shure you follow the directions on how to update the firmware.
Here is the link:
(link)
Good luck Carl
Michele Berti , Feb 14, 2005; 05:06 p.m.
I had that error last week on my 10D. After that the AF didn't work anymore properly. Now it is to Canon assistance. :-(
Good luck!
Mark U 
, Feb 14, 2005; 07:27 p.m.
The only Sigma 400 f/5.6 lenses that work on the EOS 30 and most later bodies including DSLRs (the 1D being an honourable exception) without having been rechipped were a few at the end of the production run of the APO version, and the APO HSM version. I would be surprised if your 400 f/5.6 worked with an EOS 30 but gave Err 99 when stopped down on a 20D - but if you had an EOS 300 this would make sense. Can you confirm which body you had?
If you look here you can see the list of lenses that Sigma can currently rechip:
(link)
this might include your 28-105 (check the exact lens description - as with many Sigma lenses, there are several very similarly named versions), but not your 400. To double check, contact Sigma in your country with full details of your lenses (exact model name and serial number). If you really were able to use your 400 on an EOS 30 and your 20D already has current firmware, then the symptoms suggest that the aperture mechanism has developed a fault (sticking aperture blades is one possibility), and the problem might be repairable.
Early versions of the 20D firmware (prior to 1.0.5) did cause lockups with lenses from all manufacturers, including Canon and Sigma - so it's certainly worth checking and installing the latest firmware. However, I'm not aware that the latest firmware (1.1.0) has any updates that affect lens compatibility compared with 1.0.5.
It would be very interesting to know exactly which lenses Carl has that didn't work on which earlier firmware that are now working with 1.1.0. Can you give details, Carl?
It is just possible that Canon have improved compatibility without saying anything - one user who had been having trouble with a Canon 70-200 f/2.8 L IS locking up reported no problems since upgrading his firmware, but this could be just a coincidence - see this thread:
http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00B7sm
If it is true that compatibility has been improved, not only will owners of problem Canon 70-200s be happier, but also it would open up some bargain priced good quality optics from Sigma (and probably Tokina) that don't work with many other recent bodies.
Having delved a bit into the technology of the EF mount, I'm not as pessimistic as Bob about future compatibility of Sigma lenses made since 2001. So long as Canon maintain compatibility with their own lenses, I think third party ones will also remain compatible - my reasoning is in this thread:
http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00B3Y8
Henri k , Oct 23, 2005; 01:04 a.m.
Just my 2 c worth:
I do have a two weeks old EOS 20D. Lense are Pro serie from Canon:
- 70-200 f 2.8 L IS USM
- 24-105 f 4 L IS USM
Flash cards: 1 Gbyte Sandisk extreme III
So I was 'sort of confident' that all the problems with err 99 mentionned in numerous forums should not get to me..
Well I was wrong.. I got the darn error in the middle of a photo shot!
I've tried everything mentionned in various forums:
- Shutdown the camera, take off the battery for 30 seconds and restart.
- Change lenses and do the same 'cold' reset.
- Tried to connect to mains adapter (Canon one)
- Tried to clean the contacts on both Canon EOS20D and lenses..
Well all that in pure lost of time!
Body is going back tomorrow to canon repair centre!
So much for a 'reliable' body !
(Just in case you didn't notice .. I'm furious)
