Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Thread Tools Search this Thread
Old Jan 12, 2009, 9:05 AM   #1
Senior Member
kazuya's Avatar
Join Date: Sep 2008
Posts: 994

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
kazuya is offline   Reply With Quote
Sponsored Links
Old Jan 12, 2009, 11:30 AM   #2
Senior Member
Wingman's Avatar
Join Date: Dec 2003
Location: Hebron, Kentucky (northern Kentucky/Greater Cincinnati):KCVG
Posts: 4,297

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.

Wingman is offline   Reply With Quote
Old Jan 12, 2009, 12:08 PM   #3
Senior Member
a200user's Avatar
Join Date: Aug 2005
Location: Western New York
Posts: 942

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.
a200user is offline   Reply With Quote
Old Jan 12, 2009, 1:34 PM   #4
Senior Member
penolta's Avatar
Join Date: Apr 2007
Location: California USA
Posts: 5,206

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).
penolta is offline   Reply With Quote
Old Jan 12, 2009, 2:48 PM   #5
Senior Member
kazuya's Avatar
Join Date: Sep 2008
Posts: 994

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

kazuya is offline   Reply With Quote
Old Jan 12, 2009, 4:10 PM   #6
Senior Member
Goldwinger's Avatar
Join Date: May 2008
Location: Winter Haven, Florida
Posts: 6,515

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.

Goldwinger is offline   Reply With Quote
Old Jan 12, 2009, 6:09 PM   #7
Senior Member
Trojansoc's Avatar
Join Date: Jan 2007
Location: Hot Springs, AR
Posts: 3,723

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.


Trojansoc is offline   Reply With Quote
Old Jan 13, 2009, 4:44 AM   #8
Senior Member
beachboy2's Avatar
Join Date: Aug 2005
Location: Perth, Western Australia
Posts: 517

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

beachboy2 is offline   Reply With Quote
Old Jan 13, 2009, 6:16 AM   #9
Senior Member
rhermans's Avatar
Join Date: Jun 2005
Location: Antwerp - Belgium
Posts: 3,454

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.


rhermans is offline   Reply With Quote
Old Jan 13, 2009, 9:17 AM   #10
Senior Member
kazuya's Avatar
Join Date: Sep 2008
Posts: 994

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.

kazuya is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 9:42 AM.