# Possible Faulty Lens - Help?



## Renegrenade (Jun 23, 2010)

Dear all,

I have a Sigma 18-250mm OS HSM lens that I've had for nearly a year now and love it to bits. It hasn't been bashed about and I'd like to think I generally take good care of it.

However, since about January/February, I've noticed that occasionally I get an error when using it on my Rebel T1i (500D). I noticed it first when trying a bit of soft zoom-burst photography on a tripod (nothing harsh, very gradual) where I'd get an error message, something to do with the connection between the lens and the camera coming loose? I remove the lens and re-attach, and then it's OK again until the next time the error occurs.

The lens was also tried on a friend's 400D taking regular static photos and it also gave periodic errors which required turning the camera off and on.

Has anyone had this or a similar problem before and knows what's wrong with the lens? Visual inspection does not suggest any bad contacts or loose mechanical parts.

Cheers!


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## Derrel (Jun 23, 2010)

Renegrenade said:


> Dear all,
> 
> I have a Sigma>SNIP> what's wrong with the lens? Visual inspection does not suggest any bad contacts or loose mechanical parts.
> 
> Cheers!



It's a Sigma...the nickname used to be SIG_nifcant_MA_lfunction...this is unfortunately an issue that is pretty common with Sigma lenses on Canon bodies...on Canon bodies of the EOS persuasion, the lens diaphragm is 100 percent entirely electrically controlled and interfaced with the camera, and the contact-to-contact quality between an EOS body and its lens is critical for operation...none of those 51-year-old mechanically actuated diaphragms like Nikon uses in all their lenses and all their bodies....the Canon EOS system,well, it's ALL-electronic, and this type of Error is unfortunately part of the territory, and it seems worst with third-party lenses.

I myself own a couple of Sigma lenses in Canon EF mount, and one of them occasionally causes the same type of error...but then it's a cheap Sigma 18-125 DC lens...


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## KmH (Jun 23, 2010)

Plus it's a 3rd party lens. They are reverse engineered.

Things that are reverse engineered don't often work as reliably as the camera body makers stuff.


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## fokker (Jun 23, 2010)

I guess you could try cleaning the contacts on both the lens and the body. I have heard of this causing the issues that you speak of. Apparently you can use an eraser to gently rub across the contacts to clean them, otherwise probably some isopropyl or meths or something should do the trick.


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## Renegrenade (Jun 24, 2010)

Thanks for the advice, everyone. If I happened to just found out that the lens was still under warranty (but bought from overseas so I'd ship it back) and I wanted to get a replacement for it, what would I write in the accompanying letter to better describe the problem?

Many thanks!


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## Dao (Jun 24, 2010)

Maybe you can email/call Sigma UK and see if your lens is under the international warranty. (From what I read, they may have only 1 year international warranty)


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## Renegrenade (Jun 25, 2010)

Dao said:


> Maybe you can email/call Sigma UK and see if your lens is under the international warranty. (From what I read, they may have only 1 year international warranty)



Good idea. I've just rung them and apparently if I include the receipt as well as a letter explaining why I was in the US then and am now in the UK, I should be OK. They'll repair but won't replace. I'll ring the place I bought it from in the US later today when they're open and see what they say - and make a decision based on that


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## Early (Jun 25, 2010)

fokker said:


> I guess you could try cleaning the contacts on both the lens and the body. I have heard of this causing the issues that you speak of. Apparently you can use an eraser to gently rub across the contacts to clean them, otherwise probably some isopropyl or meths or something should do the trick.



Tru dat!  It's such a low voltage used by electronics that even a thin film of corrosion will it.  That's why better equipment use gold contacts.  

It's fairly common to lose connection between a flash unit and camera.  A simple pencil eraser should do the trick.

I don't know about using solvents around the camera though.


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