Just a note to any of you out there with a Sigma 28-200 DL Aspherical Macro Zoom and a EOS30 body. I found that the auto-aperture on the lens would not work with this body - basically it stays fully open. Looks like Canon have been messing around with the parameters of the lens controls, which just puts them outside tha range of the Sigma inputs. However on calling Sigma in the UK, they have a scheme to update any of these lenses for a nominal £5, just to cover the return postage. If you have this probelm, get in touch with Sigma, and it looks like they will be able to sort you out.

-- Chris Nutt (chris@nutt01.fsnet.co.uk), April 08, 2002

Answers

You're placing blame in the wrong place.

Canon are under no obligation to make the cameras work with third party lenses. Proof that canon stick to their own rules is that any of the earliest (15 year old now) EF lenses will work flawlessly with the EOS 30.

Sigma do not license the use of the lens mount or communication system, and so the lenses are not properly compatible. This is a well known problem with Sigma and tokina lenses (as well as some other third parties). Tamron lenses are mostly unaffected, because they DO license the mount from canon.

-- Isaac Sibson (isibson@hotmail.com), April 08, 2002.

Looks like Canon have been messing around with the parameters of the lens controls, which just puts them outside that range of the Sigma inputs.

Do you really think that Canon is messing up with the parameters. Then why does all original EF lenses from Canon works with all EOS bodies without problem, unless either of them is malfunctioning.

-- sajeev (chack74@yahoo.co.in), April 08, 2002.

This is just another report of a very common problem with some third party lenses, and most notably with low-end Sigma lenses. It seems every time that Canon releases a new body there are a bunch of older Sigma lenses that won't work with them.

However, I'm not so sure that Canon is entirely without blame in the matter. I wouldn't be surprised at all to find out Canon was indeed making changes to the body/lens communication scheme just to frustrate Sigma & discourage buyers of all third party lenses. If have been around computers for a while you might remember the old (supposed) Microsoft saying, "DOS isn't done, 'til Lotus won't run." It seems, Bill Gates & company effectively killed off Lotus 123 with that policy. Who says that Canon has more moral compunction that MS?

At least Sigma does the right thing with most of their old lenses. But they do not have this policy with all their old lenses. So watch out when buying Sigma/Tokina/Vivitar/Phoenix/Cosina/etc.

-- Jim Strutz (j.strutz@gci.net), April 08, 2002.

Of course Canon may be altering things, within their own specification.

But it is the fault of the third-party lens manufacturers that this causes those lenses not to work. All Canon lenses still work, thus the fault is not with Canon.

It MAY be that Canon HAVE to alter things. The EOS 3 and EOS 1V suffer this "problem" noticeably more than previous models. Their AF performance is also noticeably faster. Perhaps some of the modifications made were in order to achieve faster focus?

-- Isaac Sibson (isibson@hotmail.com), April 08, 2002.

You certainly may be right Isaac, and that is the line from Canon, but still, I wonder...

-- Jim Strutz (j.strutz@gci.net), April 09, 2002.

As you pointed out Jim that this happens mainly in the low-end third party lenses, does this happens with Tamron lenses or ALL Sigma lenses?

N.K.Guy always says one thing when it come to buying Canon Vs other manufacturer's products (mainly camera body). He says whether you're buying just a camera or whether you're looking to buy into a system. If the former is true most likely he is not much interested in doing any serious photography in future. For that person at third party lens compactible with any Canon camera and available at that time should work. But if he wants to buy a system, he should strictly stick to Canon. Then such incompactibility problems will not come. May be the person not interesed in serious photography can think of doing it in future. Then instead of just upgrading the body he should upgrade his system to just one manufacturer.

Neither can I tell why Canon keeps on changing its parameters. May be to avoid third party sale. But then why did they licensed their mount to Tamron.

Also, Canon knows that Sigma fixes the in-compactibility problem for just a few bucks. Is this really Canon want to do. I think the reason could be different, as pointed out by Isaac.

The latest 3 stop equivalent IS on 70-200 f/2.8 will work on the oldest EOS body and the oldest lens will work on the latest bodies. Isn't that great about Canon. Also all features available in a lens can be used with any EOS body. I wonder whether this is true to Nikon. Some of their older AF bodies cannont use the full features of new lenses.

Canon give much more than any other manufacturer. So I think blaming Canon for this is BS.

-- sajeev (chack74@yahoo.co.in), April 09, 2002.

There are clearly some very strong suporters of complete Canon systems out there. That is fine if you can afford the prices of Canon lenses, which are still considerably more expensive in the UK than in the US - but that's another discussion thread, so we won't do it here. If the info is correct that Sigma have not licenced the mount info from Canon, then that should be made clear when reporting the "independant" tests of these lenses in Photo magazines. - or maybe that would upset the lens manufacturers who supply them with free lenses?. It would seem that the operating specs of the bodies are quite wide and Canon are (quite correctly) using this bandwidth. However that still doesn't keep you from feeling "cheated" when buying an independant lens that is supposedly compatible, when in fact it isn't. Still, full marks to Sigma for owning up and putting it right (In my case at least). Personally I'm very happy with the price/performance ratio of the Sigma lenses I have, and would have no problems in reccommending ot buying another - however amybe I'd take the boddies along just to make sure. Thanks to all of you for the interesting info. p.s I also have a Sigma 17-35mm EX zoom which works just fine on both my 300 and 30 bodies.

-- Chris Nutt (chris@nutt01.fsnet.co.uk), April 09, 2002.

Sajeev said, "Canon give much more than any other manufacturer. So I think blaming Canon for this is BS."

Hey, Im not blaming Canon. I think it's a good marketing strategy. But I *do* suspect it might be marketing strategy and not technological requirements for the new camera bodies.

Higher-end Sigma lenses seem to have less problems with future incompatibilities than the low-end lenses do. (And Sigma seems to have more problems than Tokina.) But I have had some of the better Sigmas (28-70 f/2.8 and 14mm f/3.5) that are reported to not work with the EOS 30/Elan 7. But I sold them some time before any of this was an issue.

I also have the Sigma 17-35 EX f/2.8-4 & have no problems with it. And I have never heard of any Sigma EX series lens with an incompatibility problem... yet. But I *suspect* that that time will come. Still, it's worth having this lens I can afford, than to wish for the Canon version that I cannot.

-- Jim Strutz (j.strutz@gci.net), April 11, 2002.

May be Jim, its a Marketing Stategy rather than Technological Requirement. And I think it should be done to some extend. I doubt there must be some example of malfunctioning of EOS body due to third party accessories. This could be one of the reason Canon wants to avoid third party equipments with Canon cameras. Well, there are lots of controversies to this issue.

-- sajeev (chack74@yahoo.co.in), April 12, 2002.

Isn't this one of the lenses that Sigma will fix for free?

http://www.sigma-photo.com/html/news/Elan7.htm

After I upgraded to an Elan 7 from a Rebel G, Sigma fixed my 24mm f/2.8 for free. I was impressed.

Yes, Canon hates people buying third party lenses as you can see from their advertisements in photo magazines. When buying a third party lens for EOS one has to fully accept the possibility of ditching the lens after you buy a new body.

-- Steven Fisher (steven_fisher@hotmail.com), April 15, 2002.