Sigma 10-20 HSM DC F3.5 rather disappointed !!

[Disco_owner]

Hi Guys , Hope everyone has been keeping well . I bought the Sigma 10-20 last week with the thought of going Wider for my Landscape shots.As I've been putting this lens throught it's testing , I found the Lens to be sharp in centre and Borders but the corners are really Mushy and soft . it doesn't matter how Much I stop down with the lens at the corners is still soft.

Should I have expected this ? or do I have a Bad Copy ? Has anyone had any experience with lens or it's older Brother F4.5-5.6 and would like to share your experience and field test , my first Choice would have been the Tokina 11-16 F2.8 which MTF results are very good at centre/border/corners but this lens doesn't come in Pentax K-Mount:(

Any thoughts you have would be Much appreciated.

[p38arover]

This lens, Khos?

Sigma 10-20mm F3.5 vs F4.0-5.6 - Introduction - PentaxForums.com (http://www.pentaxforums.com/reviews/sigma-10-20-comparative-review/introduction.html)

and user reviews at:

Sigma 10-20mm F3.5 EX DC HSM Lens Reviews - Sigma Lenses - Pentax Lens Review Database (http://www.pentaxforums.com/userreviews/sigma-10-20mm-f3-5-ex-dc-hsm.html)

[Disco_owner]

Hi Ron, I had read some of reviews Prior to purchasing this lens , considering some of the reviewers were stating the lens very Soft at corners when others were stating that it is just as sharp on the corners as it is in centre I thought i'd take my chances.

The Shot below was taken inside George's camera store on a Manny tripod at F22 and the corners were still very soft and Mushy so there's

been Tremendous amount of clarity and sharpness added in LR 4.1 to make this Photo Look half descent:(


https://www.aulro.com/afvb/images/imported/2012/08/1158.jpg (http://www.flickr.com/photos/80483416@N03/7755823330/)
George's Cameras (http://www.flickr.com/photos/80483416@N03/7755823330/) by Flameborghini (http://www.flickr.com/people/80483416@N03/), on Flickr

[Chucaro]

IMO Photozone have one of the best lens reviews and HERE (http://www.photozone.de/component/content/article/467-sigma_1020_35_nikon) is the review of the Sigma.
Compare the data in the review with the results of your lens and see if you have a soft copy.
Try to take shots of a large newspaper page and analyze in the PC the image.
I use a Tokina 12-24 f/4 which is excellent lens and good value as well.

Verdict for Photozone

The new Sigma 10-20 mm f/3.5 EX DC HSM leaves us with mixed feelings. The build quality of the lens is certainly excellent, distortion is a little high at the wide end (but excellent for the rest of the zoom range), there's also a fair amount of vignetting and CA, but that's typical for this lens class. Resolution in the center is excellent, borders also are nothing to complain about and corner performance is ok at 15 and 20 mm, but very disappointing at 10 mm.
In summary, it makes one wonder who's supposed to buy this lens. Those who already own the older and slower Sigma 10-20 most likely don't feel the need to upgrade, especially if they already own filters to go with the lens. Even those who purchase new will probably find the older design with its lower price point more attractive. Unless you really need the speed of this lens, but for those use cases the Tokina 11-16/2.8 is probably the more attractive option.

Still, those who do buy this lens in the end have aquired a solid performer, which delivers great results if you're aware of its weaknesses and work around them.

[Disco_owner]

IMO Photozone have one of the best lens reviews and HERE (http://www.photozone.de/component/content/article/467-sigma_1020_35_nikon) is the review of the Sigma.
Compare the data in the review with the results of your lens and see if you have a soft copy.
Try to take shots of a large newspaper page and analyze in the PC the image.
I use a Tokina 12-24 f/4 which is excellent lens and good value as well.

Verdict for Photozone

The new Sigma 10-20 mm f/3.5 EX DC HSM leaves us with mixed feelings. The build quality of the lens is certainly excellent, distortion is a little high at the wide end (but excellent for the rest of the zoom range), there's also a fair amount of vignetting and CA, but that's typical for this lens class. Resolution in the center is excellent, borders also are nothing to complain about and corner performance is ok at 15 and 20 mm, but very disappointing at 10 mm.
In summary, it makes one wonder who's supposed to buy this lens. Those who already own the older and slower Sigma 10-20 most likely don't feel the need to upgrade, especially if they already own filters to go with the lens. Even those who purchase new will probably find the older design with its lower price point more attractive. Unless you really need the speed of this lens, but for those use cases the Tokina 11-16/2.8 is probably the more attractive option.

Still, those who do buy this lens in the end have aquired a solid performer, which delivers great results if you're aware of its weaknesses and work around them.

This is were I seriously considered the Tokina 11-16 / F2.8 lens as a Wideangle zoom lens for my landscape shots prior to puchase of Sigma 10-20 but as stated it is not made in K-Mount. I've put the sigma 10-20 through it's field testing already and blown up the images on my 24" Monitor and they are very soft and mushty on corners.

There is a New Sigma 12-24 HSM DG II which is already available now , little bit more exxy but it is a FF lens in Kmount , a little bit bigger and heavier than the Sigma 10-20 DC F3.5 but I have not seen any reviews of it as yet.


Edit : Found the review on Canon 5D Mark II Body in Photozone.de

http://www.photozone.de/canon_eos_ff/676-sigma1224f4556iiff

[WhiteD3]

I had one for a couple of years and found it excellent, and sharp. Have the equivalent Canon now which is not as good IMHO.

[Disco_owner]

yeah , it's sharp on centre and Borders , but the corners are literally un-Useable , The Image I posted earlier was take at different F-Stops and it didn't matter what F-Stop I stopped down above F5.6 where the Centre sharpness was best the corners remained soft and Mushy all the way up to F11 and further . I'm going to put it through it's paces in the next few weeks and if anyone interested I will post up results. I even took shots with the same lens on a canon and 100% crop on the camera and corners are still soft and Mushy.

[Chucaro]

Have you considered the Zeiss 25mm f/2.8 ZK Distagon T* ?
It is available for Pentax and the optics are superb.

[Disco_owner]

Chucaro , to honest I haven't yet considered the Zeiss 25 mm , I do have a Pentax 15mm Ltd F4 which is Superb in sharpness and IQ and very resistant to Flare but I wanted to go a little bit Wider than 15 which is why I purchased the 10-20 Sigma.:)