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11-05-2011, 11:35 AM   #1
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Faulty Sigma APO 100-300/4 EX

I just got the lens from e-Bay optically and cosmetically in very good conditions. But there is a problem: the camera doesn't read the aperture of the lens, showing "F-F" instead. However, It works properly, when the A-pins of the camera and the lens are shorten together via small piece of aluminum foil. When circuitry is measured between the tip of A-pin and lens mount the multimeter reads open circuitry. I was told that it is wrong and it should read short for properly working lens. And that in my case I deal with a faulty A-switch. Could anybody confirm that my troubleshooting asumptions are right? The lens is definitely crippled. I have two choices: to ask for discount and keep it or to return it. When I contacted C.R.I.S. and Sigma US they refused to give me any estimates without seeing the len (it's understandable). Does anybody know how much approximately such a repair might cost (I have to negotiate a discount)? And is there any work around, e.g. simple contact adjustment or replacemnt of the A-pin isolating plastic tube with the metal one to create a constant short of the pin to the mount. IMHO the latter will disable manual aperture adjustment, setting the lens permanently to A-mode, but I don't care. I'd like to keep this gem.
Note: please forgive me for any typo. I'm posting from the Audi dealership, while my car is in oil change service. The spell check doesn't work here for some reason. And I don't have my reading glasses with me. :ugh:

11-05-2011, 12:17 PM   #2
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That is correct the lens should be a very low resistance between the mount and the A pin when in a position. Try moving the lens in a d out of A a few times. As to what to do long term it is up to you
11-05-2011, 01:31 PM   #3
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QuoteOriginally posted by Lowell Goudge Quote
That is correct the lens should be a very low resistance between the mount and the A pin when in a position. Try moving the lens in a d out of A a few times. As to what to do long term it is up to you
Thanks. I did cycle the A-ring many times. No success.
11-05-2011, 02:12 PM   #4
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Depending on the ebay listing, you might have a recourse. Did the listing state there were problems with the lens or that it was being sold as is?

If the lens is in otherwise great shape and you got it for "cheap" it might be worth sending to get repaired, calibrated, and cleaned.

11-05-2011, 02:31 PM   #5
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QuoteOriginally posted by George Lama Quote
Depending on the ebay listing, you might have a recourse. Did the listing state there were problems with the lens or that it was being sold as is?

If the lens is in otherwise great shape and you got it for "cheap" it might be worth sending to get repaired, calibrated, and cleaned.
The lens condition was "Mint". I can't blame the seller: when off the camera the aperture is smooth and snappy. But still it's crippled. And it was not cheap, nor overpriced: $925. However, $1000 insured roundtrip shipping to Sigma, NY will cost me about $70-80 in addition to repair cost itself. I'd like to negotiate monetary refund with a seller, but can't figure out how much such fix is going to cost me. Of course I can return it - it's covered by e-Bay buyer protection. But I rather fix and keep it.
11-05-2011, 02:34 PM   #6
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Yeah, if it's in as good as condition as you say, then I would definitely keep it. Get some type of compensation from the seller then send it off for repair. It sucks to have to deal with all of that, but it's a great lens and in the end, it's worth it. There's no guarantee that you'd be able to find another one in such good condition any time soon. You may, but you may not and you've got one in your hands right now.
11-05-2011, 04:02 PM   #7
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The 100-300mm ex dg I had reported the ex if wrong when in A and I think it was common to show up as a 70-200mm f2.8 so I used the aperture ring on mine mostly. Just something else you may want to check, a great lens any ways! :-)
11-05-2011, 07:45 PM   #8
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QuoteOriginally posted by borno Quote
The 100-300mm ex dg I had reported the ex if wrong when in A and I think it was common to show up as a 70-200mm f2.8 so I used the aperture ring on mine mostly. Just something else you may want to check, a great lens any ways! :-)
When the A-pins are shorten through the foil the lens EXIF is is fine. But the lens is still crippled. Have anybody had any estimation/repair relationships with Sigma US? Or, could somebody recommend a trustworthy and not overpriced repair shop?

11-05-2011, 09:14 PM   #9
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QuoteOriginally posted by Greyser Quote
When the A-pins are shorten through the foil the lens EXIF is is fine. But the lens is still crippled. Have anybody had any estimation/repair relationships with Sigma US? Or, could somebody recommend a trustworthy and not overpriced repair shop?
I can't recommend anyone specific, but surely there is one somewhere in LA. I would just call a bunch of camera shops to see if any names come up repeatedly as being recommended.
11-06-2011, 08:48 AM   #10
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I've only had warranty repair done directly with Sigma so I can't speak as to cost.

However based on your description of the problem, the lens might have been claimed to be in Mint condition, however it's not. It's not like your camera is causing the problem, so the seller should have noticed the same problem.

I'd negotiate with the seller to agree to a repair/shipment to Sigma or a full refund. I'm sure he'd rather not lose the sale.
11-06-2011, 09:24 AM   #11
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QuoteOriginally posted by George Lama Quote
I've only had warranty repair done directly with Sigma so I can't speak as to cost.

However based on your description of the problem, the lens might have been claimed to be in Mint condition, however it's not. It's not like your camera is causing the problem, so the seller should have noticed the same problem.

I'd negotiate with the seller to agree to a repair/shipment to Sigma or a full refund. I'm sure he'd rather not lose the sale.
That's exactly what I'm going to do. It also back focuses. I'l try to fix BF issue via micro adjustment. I not, there is no choice and I return it.
11-06-2011, 12:35 PM   #12
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You might find the BF to require over -10 (both my Sigma lenses had that problem). I sent them in to Sigma and they adjusted plus updated firmware on lenses.
11-06-2011, 06:48 PM   #13
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QuoteOriginally posted by George Lama Quote
You might find the BF to require over -10 (both my Sigma lenses had that problem). I sent them in to Sigma and they adjusted plus updated firmware on lenses.
George, You are right in time. I spent almost a day today trying to adjust BF and comparing the Sigma to my DA*60-250 and FA*300. The absolute winner is FA*300/4.5. The next goes DA*, and then the Sigma. When the 1.4x TC is attached FA* doesn't show any compromises. The Sigma gets much worse. I believe the adjustment, as you said, is beyond 10. I almost decided to send it back and then got your message. How much did you pay for the service? And did you send both the lens and your camera for adjustment? One more question: what parcel service did you use? I need a roundtrip $1000 insured shipping to NY city, and it looks like it's going to be very costly.
BTW: The Sigma was fully functional, but crippled with A-pins shortened via piece of aluminum foil.
11-06-2011, 07:16 PM   #14
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QuoteOriginally posted by Greyser Quote
I need a roundtrip $1000 insured shipping to NY city, and it looks like it's going to be very costly.
It shouldn't be too bad. Either USPS Priority (medium flat rate box should fit) or FedEx/UPS Ground shouldn't me more than $20-25 each way, even with insurance.
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