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Old Jan 12, 2009, 9:05 AM   #1
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i bought a Sigma 17-70mm f2.8-4.5 DC Macro Lens from amazon today and fist impressions are not good, ok ive only taken a few shots with it and all indoors because its rainin very hard outside, but even so id expect it to out perform the kit lense. heres an example full size crop

and heres one with the kit lense

i will try and take some more with it later, but im not hopefull, does anyone have any advice on good ways to test lenses?

im in two minds as to if i should get a eplacement or refund, as it stands though right now im thinking ill just get a refund
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Old Jan 12, 2009, 11:30 AM   #2
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Sorry to hear about your new lens. From what you have posted, the Sigma lens definitely appears to have an issue. You can do a thorough test of the lens and focusing accuracy by using the tools at following: http://www.dphotojournal.com/focus-test-chart.pdf.

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Old Jan 12, 2009, 12:08 PM   #3
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I was considering the Sigma 17-70mm f2.8-4.5within the past year. A local shop had them in Pentax mount at a very good price so I took my K100D into the shop and they let me try one out. I did some comparisons with the Da 18-55Kit lens in their shop and outside their shop on a sunny day. Although I had seen good reviews on the Sigma I was not impressed. It was no worse than the DA kit lens, but for US$320 it wasn't much better either.

They offered me a very good price on the DA*16-50mm but I couldn't afford one.

I wanted to keep the purchase at or under the price of the Sigma 17-70mm.

The alternatives were the Sigma 18-50mm marco and non-macro versions with constant f2.8. Macro version has good reviews but it's over US$400. Tamron has a 17-50mm Di II constant f2.8, but also out of my price range.

I found a Sigma 24-60mm EX DG constant f2.8 for US$200. It's on my K100D all the time, it back focuses a bit, but I managed to get into the debug menu of the K100D and corrected for that. I don't miss the wide end all that much (18mm to 24mm).

Anyhow, to make a long story short, I was not impressed with the Sigma 17-70mm either.
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Old Jan 12, 2009, 1:34 PM   #4
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The Sigma EX DG 24-60 F2.8 originally sold for $400 or more, so the $200 close-out price is a bargain (it has been replaced by a 24-70), but they have gotten hard to find now at that price (or at all).
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Old Jan 12, 2009, 2:48 PM   #5
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heres a couple more pics full size crops straight out the camera using flash and tripod

this is the sigma shot

this is the pentax

its better but there doesnt seem to be much difference in sharpness, i had expected better and from from what you guys have said, i think ill get a refund and get something else

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Old Jan 12, 2009, 4:10 PM   #6
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Hey Dave,
sure does look like there is a problem with your copy of the Sigma. I've heard they have a quality control issue with some of there lenses. hope you get your refund back OK.

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Old Jan 12, 2009, 6:09 PM   #7
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When my kit lens was among a group of lenses stolen last summer, I replaced it with the Sigma 18-50 EX DC f/2.8 non-macro. It has become a workhorse lens for me, and I couldn't be more pleased.

It certainly does appear that you have a problem with that particular copy of the 17-70.

GW mentions some of the comments about QC control issues on some of the Sigma lenses. Maybe I've been lucky, but I've never had a problem with a Sigma and I have the 18-50, a 28mm f/1.8, a 28-200, a 70-200 f/2.8, and the 50-500 (Bigma). In addition, I have the 1.4X and 2.0X Sigma APO teleconverters. Not a bad lens in the bunch.


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Old Jan 13, 2009, 4:44 AM   #8
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Hi kazuya
I have a number of Sigma lenses and am happy with all of them. Two comments.

Firstly go for the EX range. Presumably you are after quality, and these are the better (although more expensive lenses).

Secondly, before you give up on this new purchase, check with the focus chart whether front or back focus is an issue. As you have a K20D, I assume you know how to do that. I check and adjust all new lenses. Sometimes only minor adjustment necessary but in the case of one lens (10-20mm DC EX) I have it adjusted to either +5 or -5 (I forget which). The K20D remembers the setting for each lens.

Good luck

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Old Jan 13, 2009, 6:16 AM   #9
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Sorry to hear, and see that the lens isn't preforming.
I would go back and here what they say about it, if needed get a refund.

I've got two sigma's a 100-300ex f4 and the 10-20ex and both are great.
But as bb2 said they are ex versions.


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Old Jan 13, 2009, 9:17 AM   #10
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thank you for all your replies,

ive been back on amazon.co.uk and done the returns form, "replacement" was greyed out so ive no choice but to take a refund.

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