Camera Labs

I just ordered the above lens, to test it thoroughly. A lab-test is looking too good here and the resume sounds like this lens is a real winner
This might be down to the fact that Sigma designed this lens as a FF-lens, so on a APS-C sensor it showed very little distortions and vignetting plus very high border sharpness!
I'll compare it to a second copy of Sigma's 10-20mm, a Tamron 11-17mm and a Tokina 12-24mm.
I'll keep you posted!

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Here are the main facts from the catalog:
Size: 87x100mm = big
Weight: 615g = fat
This zoom is the biggest, fattest ultra-wide zoom. For the reason, see below...
Optics: 16 elements in 12 groups = too much
Closest focus distance/max.magnification: 0.28m / 1:7.1 (I'll test this!)
Filter-thread: normally not , only in the additional lens-cap-holder 82mm (=hugh=expensive). Using the lens-cap-holder limits the use of filters to above 14mm due to vignetting alternatively gel-filters can be used (=exotic)
No IS = not so important
AF-S, so works on D40/x-bodies , easy manual-focus override (just turn the focus ring)
Ah, and it covers FF-sensors . This is also the reason for the huge size/weight and the price-premium of this lens. This is a "real" 12mm on FF-sensor bodies! And this should also be the reason why some tests show exceptional marks in vignetting, distortions and corner-sharpness on APS-C bodies - normally a problem-zone for ultra-wide zooms!
Comes with a lens-bag and the lens-shade is built-in
Price: around 560€ = the second most expensive (after the Nikon 12-24mm)
--> Addendum: And the rear lens-cap is cr*p: can be put on in only one position
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Nice story from the etailer that sold me this lens: "No, you cannot use this on a cropped-sensor digital-camera, it gives you a fisheye-view from 14mm and below and it has strong vignetting. It's only ok on FF-sensors and film-cameras!". Boy did I laugh They forgot to pull the lens-cap-holder off

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Here are my first impressions and observations from working with the lens:
A monster of a lens! Watch out for the protruding front-lens.
AF is fast and quiet (enough) but in some situations seems to focus at 2m (see here with AF) instead of infinity (see there with MF) I'll test that thoroughly, as the dof of a wide-angle is shallower than many people think. So perfect focusing is essential to sharp pics even on a wide-angle.
The zoom ring is quite tight and a little too small for my liking. I would have preferred to have the zoom-ring in front.
The focus-ring does not turn with AF. That's good
The rubberized rings feel ok.
The lens has dof-markers at f5.6 and f8 But you don't know which focal length they are valid for
The low distortions are immediately visible: everything is straight. Incredible for such a wide-angle lens. See e.g. the following pic at 12mm (clickable):
.
All test-photos are collected here
And the built-in flash causes a "nice" shadow @12mm: see on the right side of the door frame

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Well, let's at least start some of the test-reporting.

Let me get off with a personal remark: I really was fascinated by this lens. It was the largest, with the ugliest bulging front lens I had ever seen, a monster for an ultra-wide!
(See the ugly duckling in this shot third from left, almost dwarfing the 18-200mm and the 80-400mm!)

But it had a mission: Full-Format, FF (or FX as Nikon now likes to call it (= pure, unneccessary marketing trickery) or the "Final Frontier" as I'd like to call it. FF is on the agenda now that Nikon switched to reverse with the D3. And they're right: FF is the only way to get more IQ than with APS-C! Canon has long understood that , and I was quite astonished that it took Nikon so long to understand that some of their customers are looking for the ultimate IQ.
So Sigma is to be applauded for the widest zoom on earth for FF! And why should this not benefit the aspiring APS-C user? You get very low distortions and very low light fall-off (tested and proved) on any smaller-than-FF sensor. Plus the lens handled like a charm (as did its smaller brother, the 10-20mm).

So this lens was sitting on my camera a lot of times and you could feel its effort to collect all the light from all the angles and hammer it on the sensor. And I love a lot of photos I made with this lens and almost couldn't make up my mind to send it back (thinking of a special "collectors" place on my shelf for it).
See one of my favs (@ 12mm, f/4.5, 1/1000sec, ISO 200)
)

So my standard question: "Could you make great photos with this lens?" has certainly to be answered by a resounding "Yes!"

But ultimately I sent the lens back because of the following reasons:
(1) The overlap with a 18-xxx zoom is too large, only 6mm (between 12 and 18mm) are the real extension over what I could do before. In FF/FX-world that argument would have been invalid, because there is no standard 18-70/105/200mm zoom. There, a 12-24mm would have fit perfectly. Alas, I'm only owning a cropped-sensor cam...
(2) the lens had some serious issues in contra-light that I'll show you in detail
(3) the lens had some prominent color-fringing, that you'll see too in the full report.
-->Addendum: And as lack of distortions and light fall-off are not very high on my must-have list those advantages did not outweigh (1)-(3).

Let me add some comments regarding comparison to the Sigma 10-20mm. This lens has almost the same probs described in (2), but color-fringing is much better controlled and the range of 10-20mm is clearly more attractive for non-FF users.
I'm also very open in saying that the color fringing with the 12-24mm never happend to bother me in one of the real-life shots. But it was so prominent in test-shots, that I believed that it would have nagged me sooner or later. But this may be just a misjudgment on my side coming from looking to closely at too many test shots and slowly beginning to become a pixel-peeper.
What a sad thought

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Thanks for the report. Both you and Klaus have seen this colour fringing and, with winter coming on and lots of bare branches to frame those landscapes, I think the fringing would definitely be an issue for me. Now that I have ruled out FF for a few years I may well need a shorter lens than my current minimum of 24mm so your thoughts are appreciated.

By the way, you need a more modern bike!

Bob.

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OM-D E-M5 + ED 12-50mm, H-PS14042E, H-F007014E, L-RS014150E, M.ZUIKO DIGITAL 45mm 1:1.8.
Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.

Well, that was the reason, I put my bike up there in the first place
[/off-topic]
[on topic]
As a Canonite, you must be considering the Canon 10-22mm!?

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Now here is a collection of shots to show sharpness (center and corner, at 15mm/f8 ) in a real-life shot and under (near) lab-conditions (at 12mm/f4.5) plus some ugly contra-light and fringing shots. I've commented on the shots, but you can draw your own conclusions...

Sharpness, real-life:



Look at the border crop against the bright sky and decide for yourself: Is color fringing a "real" prob with this lens?

Sharpness in the lab:



The grey disk is 7-8mm in the centre-crop and around 8mm in the upper-right corner, with not much of astigmatism. But as you can see the contrast in the corner is noticebly lower than in the centre-star. If you bother to have a look at the other Siemens-Star in the lower-left corner (click on the large photo and at flickr choose "all sizes" and then "original") you may also notice that this star is quite well resolved in the outer area (similar to the Tokina 12-24mm). So all in all I would not put this lens down on sharpness.
Also interesting is the light brownish halo around the grey disk. I have not really seen something like this in other test shots. Perhaps it has to do with color-fringing at a specific frequency? But I really don't know. Any thoughts about this phenomenon?
There are other test-shots at f8 and 24mm and also at 1:10 magnification in my flickr portfolio, just search for "Sigma" AND "1224mm" AND "Siemens-star" like this.

Following is a shot from a test-pattern on my monitor that shows geometric distortions, corner-sharpness and color-fringing (all in one shot, quite amazing ). It was taken at 12mm/f4.5, the most challenging setting. Both crops are at 100% for those pixel-peepers like me. The first from the upper-left corner, the second from somewhere in the middle (sorry for the large size):


You can see a huge difference in color fringing in both crops! Don't forget that both are at 100%. Perhaps this is proof (again ) that the lens has a defect, as the corner sharpness is quite even, so the shot was taken under good conditions

Flare and ghosting at 20mm/f5.6 (dead on is always the worst-case scenario!) and at 12/f8:


Unfortunately this is not only a problem under lab-conditions but also with real-life shooting. I had more than one photo looking like the following:


And then there is some focus issue! It was a dreaded moment, as I encountered numerous focus-errors with the 1st copy of the Sigma 10-20mm. So sometimes, when I made a test-shot, I looked at the distance-scale. And there was one situation where I wondered why on earth the lens had focussed to 2m: I was shooting in a wood up into the canopy, the focus indicators of my D80 clearly showed the focus points being at the leaves up in the trees (at least 10m distance!). So 2m vs 10m made me think and repeat the shot with manual focus to infinity (the lens was set to 12mm/f4.5). The first shot was on AF, second with MF (both 100% crops, also show some amount of real-life color-fringing):

As you can clearly see, 2m was not the optimal focus distance

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Ok, just wanted to inform you that the above test-report is now finished. Have fun, and shoot any questions you might have in my direction...
Oh and by the way: This lens can be had for Nikon, Canon, Sony, Pentax, Sigma mount.
And see all the test-shots here.

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Congratulations on a very thorough review of the Sigma AF 12-24mm 4.5-5.6 EX DG Asp IF.


You are right. The EF-S 10-22mm f/3.5-4.5 USM is hard to beat if you own a "cropped" Canon. Unfortunately, as an EF-S lens it isn't compatible with that "5D MkIII" I have promised myself for my 60th birthday - still some years away thank goodness! So the choice is to go for the ultra wide-angle now or spend nearly the same money on an EF 17-40mm f4L USM which, when fitted on a full frame camera, can deliver similar wide-angle performance to the 10-22 on my 40D. I think I will stick with my 24-105L for now - the cheapest option of all!

Bob.

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OM-D E-M5 + ED 12-50mm, H-PS14042E, H-F007014E, L-RS014150E, M.ZUIKO DIGITAL 45mm 1:1.8.
Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.

Well, if you look at my pics, you'll see that the color-fringing- and flare/ghosting-monster is only rising its head under special circumstances. So you might be tempted to get that lens and be a happy shooter now plus when your FF-body arives, as this is the widest FF-zoom ever - and I suspect for a long time...

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

And I just uploaded two new pics that show the ugly flare and how to avoid it: just put your hand up to shadow the lens
Without anything:


With handmade lens-shade:


There you get it: 1% effort = 100% effective

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Hi Thomas
Enjoyed reading your review on the Sigma 12-24mm nice photos too .
Is this lens really that average, i was saving hard to buy one as it would go well with my Canon 30D and Canon 1V film cameras and give good wide angle on both, though not so wide on the 30D.
Maybe there might be an alternative out there but i am not sure what within that price range.
Anyone out there with any thoughts on what might be ideal?
Cheers and thanks for reading this.

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Graham
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Sony A900 DSLR 24-70mm F2.8 ZA SSM Vario-Sonnar
Panasonic Lumix DMC-LX3
See my Flickr account

Graham, this lens is not really average. Look back three posts at my comment on Bob's post.
I was really sad to give this lens back and keep the Sigma 10-20mm as this clearly outperformed it. And esp. with a Canon-body having a 1.6x crop-factor, the wider angle of the latter lens is a clear benefit over the 12-24mm (and I was not really thinking of going FF any time soon).

But I urge you to have a close look at all the photos I posted here (all in high quality full-res.)! In most of them you don't see flare/ghosting or any critical amount of fringing. So don't let you be put-off by my critical remarks. As I said: I was only buying one lens and the Sigma 10-20mm came out on top. If I had the FF D3-body or a Canon 5D I certainly would have kept the Sigma 12-24.
Just let your eyes be the judge!

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Hi Thomas,
Thanks for your quick reply.
I think the best thing to do is go to my local photo store try the lens on my camera and see how it handles.
Your Hi-Res real life photos have convinced me to give it a try.
Thanks again

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Graham
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Sony A900 DSLR 24-70mm F2.8 ZA SSM Vario-Sonnar
Panasonic Lumix DMC-LX3
See my Flickr account

Btw. Color-fringing can be reduced by shooting RAW and using CaptureNX as a converter to jpg. See the result from the same picture as posted above but this time not the direct jpg from the camera but processed through CaptureNX:


So you have to keep this in mind, when you buy this lens: Shooting RAW can seriously reduce the effect of color-fringing with this lens!

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses