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11-13-2007, 05:15 PM   #1
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BITE ME Sigma 20mm f/1.8

I bought a Sigma 20mm f/1.8 I thought it would be the prefect addition to my bag.

It's incredibly well made -- too bad I haven't shot one in-focus picture.

I think I'm going to send it back to Dell -- they had a good price last week.

I wonder if I should even bother with a replacement. 400 bucks is a lot of money -- I could probably spend it on something else.

I've included two pictures. The back-focused picture is the Sigma at f/1.8. The correctly focused picture is the Pentax SMCP-FA 50mm at f/1.4

I took a bunch of photos in the backyard before downloading this chart -- everything was badly back focused.

Very, Very disappointed.






Last edited by konraDarnok; 11-14-2007 at 05:11 AM. Reason: pics
11-13-2007, 05:53 PM   #2
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dont see any pictures - just red Xs
11-13-2007, 06:20 PM   #3
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Just right click the x and copy the properies where the web link is to see the shots.

Wow that's the worst back focus I've ever seen anyone post. I assume you were fairly close to the test chart and it looks like it was off by 22-24 mm's. So it may be just one lens and I guess it comes down to how much the shipping will cost for a return and getting another. The FA20mm Pentax is a great lens but used will cost you at least $100 more and is slightly slower. guess you need to decide if this focal length is something you really want.

I use my 20mm quite a bit for landscape stuff as I like that kind of shooting and it's very good for indoor stuff, both in FOV and speed.
11-13-2007, 10:37 PM   #4
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I really wish that mail order companies would test what they sell before they ship it.
How long does it take to put a lens on a camera and take 6 test shots

11-14-2007, 01:05 AM   #5
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QuoteOriginally posted by little laker Quote
I really wish that mail order companies would test what they sell before they ship it.
How long does it take to put a lens on a camera and take 6 test shots
... that's simply not practical. Has to be pulled out of the box (carefully), attached to a camera, take the photos, review them on a computer, if it's fine then repackage the lens and sign off on it to say it was fine.

Multiply that time by the volume of orders.

Consider the cost associated with the staff involved.

On top of the extra equipment required just to do that, like numerous camera bodies.

I've got a better suggestion. Why doesn't Sigma just fix their damn QC?
11-14-2007, 05:13 AM   #6
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QuoteOriginally posted by CJSpangler Quote
dont see any pictures - just red Xs

Did I fix it?
11-14-2007, 05:44 AM   #7
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Yep, you did. Nice title BTW.
11-14-2007, 06:04 AM   #8
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Check it out:

I wrote to Dell this Morning. These are the salient parts of their reply:

I apologize for the inconvenience this issue has caused. I will be more than happy to assist you in this regard and would take full responsibility of resolving your issue at the earliest.

Please be advised that I have set up a request to send you the lens . Depending upon product availability, your replacement is scheduled to ship within 15 business days to the original ship-to address.

You will also be receiving pre-printed, pre-paid return air bills in the box with your replacement product. Please use these labels to return the product within 10 days of receiving the replacement product from Dell.

I have taken ownership of your issue and I will follow up this case until you receive the replacement. I will keep you posted on any developments.


Cool.

I didn't mention this in my original post, but when they shipped the lens, the lens box was simply put inside the shipping box with no packing at all. When I got the package, it was all bowed out from the lens box bouncing around inside the shipping box. I think it's more than likely that the lens was damaged because of this. That's what I told Dell. I thought it was strange they shipped it that way. It would have been better to ship with no box at all, rather than one with no packing materials.

11-14-2007, 06:28 AM   #9
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Same here!
I think this is a very common problem of this lens.

Send it in to Sigma with camera. They can fix it (Lens Rom).
Took them 2 weeks.

I love it now!

After adjustment:
f1.8:


Comparison (100% Crops):



Last edited by blende8; 11-14-2007 at 06:36 AM.
11-14-2007, 06:38 AM   #10
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QuoteOriginally posted by blende8 Quote
Same here!
I think this is a very common problem of this lens.

Send it in to Sigma with camera. They can fix it (Lens Rom).
Took them 2 weeks.

I love it now!
If the replacement does the same, I'll end up sending it to Sigma. Good to know Sigma will do this. I've read spotty reports on Sigma's customer service. Glad to hear you had a positive experience. Did you have to pay for shipping?
11-14-2007, 06:50 AM   #11
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QuoteOriginally posted by konraDarnok Quote
If the replacement does the same, I'll end up sending it to Sigma. Good to know Sigma will do this. I've read spotty reports on Sigma's customer service. Glad to hear you had a positive experience. Did you have to pay for shipping?
Don't know how it is in the US, but here in Germany it worked ok. I wrote "urgent" on the accompanying letter and pushed them a bit by phone.
You have to send in body and lens. Note lens and body number and all removable parts (battery, SD card etc.).
I have paid the send in.
I think it is worth the effort, definitely.
11-14-2007, 07:02 AM   #12
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That's nice CService from Dell, glad you're getting a chance to solve the problem.

Does it matter what lense you use with a back-focus chart or do these charts come specific to a camera and lense.
11-14-2007, 07:17 AM   #13
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It seems that the Sigma 20mm F1.8 can be repaired. My 18-50 2.8 and 70-200 2.8 have front- and backfocus problems. I sent them to Sigma two times. The first time they gave it back without repairing it. They were not able to do it. I should send them my camera, then they can program the lens ROM. So I sent them the lenses again and my Ds. A few days later it all came back. Not repaired! Now they told me they can't program the lens ROM of these lenses because it's too old. I have two lenses I can't use properly. The 18-50 lies anywhere in the corner (it has backfocus at f2.8, frontfocus at f8). I replaced it by the DA 16-45. But the 70-200 can't be replaced in the moment. I need a 2.8 for sports. So I use and take a lot of photos to have some good.

The_Lion
11-14-2007, 07:26 AM   #14
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QuoteOriginally posted by JCSullivan Quote
That's nice CService from Dell, glad you're getting a chance to solve the problem.

Does it matter what lense you use with a back-focus chart or do these charts come specific to a camera and lense.
You can download the chart and read the guy's methodology here:

Nikon D70 Focus Chart
11-14-2007, 09:16 AM   #15
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Thanks for that link konraDarnok.
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