Faulty Sigma 10-20mm?

Zwiz · 1st of January 2008 (Tue)

Hello,

I've had the Sigma 10-20mm for a few months now. Some of the images are incredibly sharp but sometimes, the left side is really bad. It's not easy to pinpoint the problem since it is intermittent. It will rarely show at 10mm or when the image is oriented vertically! But from 12mm to 20mm, I would say 1 image out of 3 has the left side out of focus.

Here an image here that demonstrate the problem.
Please, tell me what you think!

Sigma 10-20mm at 12mm, f/8, 1/400sec, ISO 200, on tripod.
Full image (no crop, resize 33%):

Cropped image (100%): looking at the streets name, you can see the exact point where the lens begins to show focus problem:

tekkie · 1st of January 2008 (Tue)

thats really weird, I think your lens is messed up

TeamSpeed · 1st of January 2008 (Tue)

I would call Sigma and send that in. It appears a lens is off axis just a bit inside.

Here is a thought, there aren't any smudges on the back end of the lens (side that connects to the body), are there?. The closer a smudge or any dust/dirt to the sensor, the more impact it will have on the photos.

Tee Why · 2nd of January 2008 (Wed)

Looks like the focus is on the ladder on the right.
Try some controlled testing. It is was due to a lens defect, I'd expect to see it in all the shots so I'd suspect user error over lens defect.

azpix · 2nd of January 2008 (Wed)

Quote:

Originally Posted by Tee Why

Looks like the focus is on the ladder on the right.
Try some controlled testing. It is was due to a lens defect, I'd expect to see it in all the shots so I'd suspect user error over lens defect.

i concur with the above.

do you have more photos with the lens?

MagentaJoe · 2nd of January 2008 (Wed)

This appears to me to be a decentered element or two. As they move this will change the way the light path is transfered from one element to the next. Depending upon how zoomed and where the focus is the effect will vary. Just a guess...

form · 2nd of January 2008 (Wed)

I had a decentered element in a sigma 10-20 before; I got it replaced with a slightly less center-sharp lens, but one with no decentering issues.

Zwiz · 2nd of January 2008 (Wed)

Thx for the answers!

So, it could be a decentered element... Ok, I'm getting my screwdriver and my ruler right away and I'm going to do do a job on this lens. More seriously, this lens is going to Sigma. "Form", did Sigma replace or repaired your lens?

Here another one, again at f/8 on tripod. Note: this is a test image, nothing artistic about it!

Full, resized to 33%

Crop 100% Left side

Crop 100% right side

kevin_c · 2nd of January 2008 (Wed)

I think this was/is a common problem with this lens. I'd be sending it in for repair.

form · 2nd of January 2008 (Wed)

Neither; Sigma accused me of getting a grey market lens (serial number discrepancy), and said "send it in and we MIGHT consider repairing it under warranty," but the original reseller was willing to replace it.

As far as I understand, this is not necessarily the standard treatment from Sigma, but it still soured me towards them.

Tony-S · 2nd of January 2008 (Wed)

Quote:

Originally Posted by form

Neither; Sigma accused me of getting a grey market lens (serial number discrepancy), and said "send it in and we MIGHT consider repairing it under warranty," but the original reseller was willing to replace it.

As far as I understand, this is not necessarily the standard treatment from Sigma, but it still soured me towards them.

Sigma USA won't repair grey market lenses as they are not responsible for them. The greys also come with a 1 year warranty from Sigma Japan (requiring sending the lens to Japan), while the Sigma USA EX lenses come with 4 year warranties for repair in the USA.

form · 2nd of January 2008 (Wed)

The seller was verified and genuine, and it was NOT marketed as grey market. If it was a grey market lens, then the head of the company lied to me directly (I spoke with him).

Tony-S · 2nd of January 2008 (Wed)

That's a bummer. I always buy my EX lenses from B&H since they only get theirs from Sigma USA. That way, all I need is the receipt that shows B&H's logo to verify it's legit. I get my non-EX Sigmas from Sigma4Less, which are usually grey market and only have the 1 year warranty anyway.

I hope you got your problem resolved satisfactorily.

Tee Why · 2nd of January 2008 (Wed)

The image looks slightly tilted down and not perfectly aligned, but to me, it does look more like misaligned lens/optics.

I'd send it into Sigma.

KnightRT · 2nd of January 2008 (Wed)

I had four of these lenses that looked exactly like yours. All were decentered, and three were Amazon RMA replacements. The last, I sent to Sigma. It came back significantly worse than how I sent it.

I gave up and bought a 10-22, despite the fact that I think the 10-20 is at least as good. One hopes you'll have better luck.

1st of January 2008 (Tue)	#1
Zwiz Member Join Date: Jul 2004 Location: Montreal Posts: 152 IMAGE EDITING OK	Faulty Sigma 10-20mm? Hello, I've had the Sigma 10-20mm for a few months now. Some of the images are incredibly sharp but sometimes, the left side is really bad. It's not easy to pinpoint the problem since it is intermittent. It will rarely show at 10mm or when the image is oriented vertically! But from 12mm to 20mm, I would say 1 image out of 3 has the left side out of focus. Here an image here that demonstrate the problem. Please, tell me what you think! Sigma 10-20mm at 12mm, f/8, 1/400sec, ISO 200, on tripod. Full image (no crop, resize 33%): Cropped image (100%): looking at the streets name, you can see the exact point where the lens begins to show focus problem:

1st of January 2008 (Tue)	#2
tekkie Goldmember Join Date: Dec 2006 Location: Clarkston, MI Posts: 2,613 IMAGE EDITING OK	Re: Faulty Sigma 10-20mm? thats really weird, I think your lens is messed up __________________ Canon 1DMKII, 7D, 5DMKII, 1D MKII Canon 500L, 100-400L, 70-200 2.8L, 17-40L, 24-105L, 24mm 2.8,50mm 1.4, 85mm 1.8, 135mm 2.8 SF, 100mm Macro Canon 430 & 580 flashes

1st of January 2008 (Tue)	#3
TeamSpeed Cream of the Crop Join Date: May 2002 Location: Cow and Corn Country, Indiana Posts: 19,793 IMAGE EDITING OK	Re: Faulty Sigma 10-20mm? I would call Sigma and send that in. It appears a lens is off axis just a bit inside. Here is a thought, there aren't any smudges on the back end of the lens (side that connects to the body), are there?. The closer a smudge or any dust/dirt to the sensor, the more impact it will have on the photos. __________________ 7D \| 100L \| 24-70L \| 70-200L f2.8 IS \| Σ 50-500 OS \| Σ 50 1.4 \| Tok 11-16 \| 18-55 IS \| 55-250 IS Past Equipment \| My Gallery \| My Mini-Reviews Resources For Sale: Focus Genie MicroAdjustment Chart \| Gel Genie Flash Gel Holder \| High ISO Denoiser Action

2nd of January 2008 (Wed)	#4
Tee Why "Monkey's uncle" Join Date: Feb 2006 Location: Pasadena, CA Posts: 10,579	Re: Faulty Sigma 10-20mm? Looks like the focus is on the ladder on the right. Try some controlled testing. It is was due to a lens defect, I'd expect to see it in all the shots so I'd suspect user error over lens defect. __________________ Gallery: http://tomyi.smugmug.com/

2nd of January 2008 (Wed)	#6
MagentaJoe psycho clown Join Date: Jan 2006 Location: Having breakfast at the circus, with the lions and the clowns. Posts: 1,357 IMAGE EDITING OK	Re: Faulty Sigma 10-20mm? This appears to me to be a decentered element or two. As they move this will change the way the light path is transfered from one element to the next. Depending upon how zoomed and where the focus is the effect will vary. Just a guess... __________________ Arguing with a psycho clown can be harmful to your funny bone. 5D-Grip, 40D, 35f2, 50f1.4, 85f1.8,100f2.8macro, 135f2.8sf, 17-40f4L, 24-70f2.8L, 100-400f4.5-5.6isL, 580ex, 420ex, 430ex, 430ez

2nd of January 2008 (Wed)	#7
form "inadequately equipped" Join Date: Jan 2006 Location: Henderson, NV Posts: 4,901 IMAGE EDITING OK	Re: Faulty Sigma 10-20mm? I had a decentered element in a sigma 10-20 before; I got it replaced with a slightly less center-sharp lens, but one with no decentering issues. __________________ Las Vegas Wedding Photographer: http://www.joeyallenphoto.com

2nd of January 2008 (Wed)	#8
Zwiz Member Join Date: Jul 2004 Location: Montreal Posts: 152 IMAGE EDITING OK	Re: Faulty Sigma 10-20mm? Thx for the answers! So, it could be a decentered element... Ok, I'm getting my screwdriver and my ruler right away and I'm going to do do a job on this lens. More seriously, this lens is going to Sigma. "Form", did Sigma replace or repaired your lens? Here another one, again at f/8 on tripod. Note: this is a test image, nothing artistic about it! Full, resized to 33% Crop 100% Left side Crop 100% right side

2nd of January 2008 (Wed)	#9
kevin_c Cream of the Crop Join Date: Mar 2005 Location: Devon, England Posts: 5,745	Re: Faulty Sigma 10-20mm? I think this was/is a common problem with this lens. I'd be sending it in for repair. __________________ -- K e v i n -- Nikon D700, 17-35mm, 28-105mm, 70-200mmVR, 50mm f/1.4 Canon EOS 3, 24-105L, 135L

2nd of January 2008 (Wed)	#10
form "inadequately equipped" Join Date: Jan 2006 Location: Henderson, NV Posts: 4,901 IMAGE EDITING OK	Re: Faulty Sigma 10-20mm? Neither; Sigma accused me of getting a grey market lens (serial number discrepancy), and said "send it in and we MIGHT consider repairing it under warranty," but the original reseller was willing to replace it. As far as I understand, this is not necessarily the standard treatment from Sigma, but it still soured me towards them. __________________ Las Vegas Wedding Photographer: http://www.joeyallenphoto.com

2nd of January 2008 (Wed)	#12
form "inadequately equipped" Join Date: Jan 2006 Location: Henderson, NV Posts: 4,901 IMAGE EDITING OK	Re: Faulty Sigma 10-20mm? The seller was verified and genuine, and it was NOT marketed as grey market. If it was a grey market lens, then the head of the company lied to me directly (I spoke with him). __________________ Las Vegas Wedding Photographer: http://www.joeyallenphoto.com

2nd of January 2008 (Wed)	#13
Tony-S Cream of the Crop Join Date: Jan 2006 Location: Fort Collins, Colorado, USA Posts: 9,250	Re: Faulty Sigma 10-20mm? That's a bummer. I always buy my EX lenses from B&H since they only get theirs from Sigma USA. That way, all I need is the receipt that shows B&H's logo to verify it's legit. I get my non-EX Sigmas from Sigma4Less, which are usually grey market and only have the 1 year warranty anyway. I hope you got your problem resolved satisfactorily. __________________ Gear list "Raw" is not an acronym, abbreviation, nor a proper noun; thus, it should not be in capital letters. Beginner's guide to printing. The PoTN film thread. 

2nd of January 2008 (Wed)	#14
Tee Why "Monkey's uncle" Join Date: Feb 2006 Location: Pasadena, CA Posts: 10,579	Re: Faulty Sigma 10-20mm? The image looks slightly tilted down and not perfectly aligned, but to me, it does look more like misaligned lens/optics. I'd send it into Sigma. __________________ Gallery: http://tomyi.smugmug.com/

2nd of January 2008 (Wed)	#15
KnightRT Member Join Date: May 2007 Posts: 64	Re: Faulty Sigma 10-20mm? I had four of these lenses that looked exactly like yours. All were decentered, and three were Amazon RMA replacements. The last, I sent to Sigma. It came back significantly worse than how I sent it. I gave up and bought a 10-22, despite the fact that I think the 10-20 is at least as good. One hopes you'll have better luck.

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