Super-wide shootout---Sigma 12-24 vs K-M 17-35

[01af]

Sigma AF 12-24 mm 1:4.5-5.6 EX DG vs Konica-Minolta AF 17-35 mm 1:2.8-4 (D)

A quick comparison on full 35-mm format (Sony A900)



At 12 mm

Sharpness

At 12 mm, the Sigma's sharpness is surpringly good in a wide area around the frame's center. Even f/4.5, which is the full aperture at 12 mm, is fully usable. Stopping down will improve sharpness as usual, but only by a minor degree. Optimal aperture for the frame's center is f/8; f/11 loses some sharpness due to diffraction.

Beginning at an image height (i. e. distance from center; utmost corner is 100 %) of approx. 75 %, or 16 mm, sharpness at wider apertures slowly starts to suffer. So near the corners, sharpness is best at f/11 which of course sacrifices some center sharpness. However the utmost corners appear blurred even at f/11 ... but that affects image heights beyond 96 % only, and mostly sagittal structures.

Lateral chromatic aberrations are very moderate. In Adobe Camera Raw, a setting of R/C -15 and B/Y ±0 or thereabouts will take care of it.


Distortion

At medium distance (approx. 2 m) there is clearly barrel-shaped distortion, but it's still acceptable for such an extreme angle of view. There is no hint of wave-form distortion (unlike the K-M at 17 mm) so it can be corrected in post-processing fairly easily. At infinity, the distortion is much lower than at medium distance---surprisingly low actually---so it will become noticable only in very critical applications. By the way, in most lenses distortion is lower at infinity and becomes worse at closer distances.


Vignetting

Boy---this lens does vignette! At 12 mm, that is. At full aperture, a smooth but firm vignetting starts out near the center, and then takes another sudden and serious rise right in the corners. When stopping down, each f-stop will reduce vignetting significantly, but even at f/11 some minor yet visible vignetting will remain.

For this angle of view, the cos^4 law predicts a natural vignetting of no less than 4.2 f-stops in the corners. Thanks to the highly asymmetrical retro-focus design, actual vignetting at smaller apertures is far less than that ... so we must consider yourselves lucky with this lens' small degree of residual vignetting. Remember---at 12 mm we really are on the far side of wide-angle territory.



At 17 mm

Sharpness

At a focal length of 17 mm the actual comparison sets in. And it's a mixed bag at 17 mm! Generally, the Sigma's performance is more even across the frame than the K-M's which is better at the center (mostly but not solely due to better contrast) but about equal to the Sigma at the edges. Actually the K-M's center sharpness is very impressive even at full aperture; optimum reached at f/5.6. And that's even though the K-M's lateral chromatic aberrations are about twice as strong as the Sigma's. By the way, the Sigma's CAs are of the red/cyan kind while the K-M's are magenta/green.

Overall, the K-M wins in the sharpness category at 17 mm. And even the full aperture---which is no less than f/2.8---is fully usable as far as sharpness is concerned; however that comes with some serious vignetting (see below).


Distortion

Big point for the Sigma here. The Sigma's distortion is a plain barrel-shape, and very low, almost zero. The K-M's is a nasty wave-form---mostly barrel-shaped at the central edges but with a pincushion twist towards the corners. The degree of the K-M's distortion, at medium distance, is about the same as the Sigma's at 12 mm but the shape is worse.


Vignetting

The K-M's vignetting at 17 mm and full aperture is about the same as the Sigma's at 12 mm and f/5.6---i. e. pretty strong. Stopping down will reduce vignetting significantly with every f-stop but even at f/8 some minor vignetting will remain. Only at f/11 it's gone completely. The Sigma's vignetting, at 17 mm, is very slighty stronger at each f-stop than the K-M's.



At 24 mm

Sharpness

With regard to sharpness, the situation at 24 mm is similar to that at 17 mm---except that the K-M's performance doesn't drop so much at the edges now. At the center, the K-M again is very strong even at full aperture, with an optimal aperture of f/5.6. At the frame's edges, the optimum is f/8. At the center, the Sigma is slightly weaker; at the corners it's pretty poor. Generally, the K-M at 24 mm (and by the way also at 28 mm but not at 35 mm) is virtually as good as most prime lenses.


Distortion

At 24 mm, distortion is virtually zero in both lenses.


Vignetting

At 24 mm, the K-M has only little vignetting. It's moderate at f/3.2, low at f/4, and virtually gone at f/5.6 and smaller. The Sigma, however, has surprisingly strong vignetting. At f/5.6 it's slightly stronger than the K-M's at f/3.2; at f/8 it's about the same as the K-M's at f/3.2.



Resumee

At 12 mm on 35-mm full-frame format, the Sigma 12-24 simply has no competition, and it does perform well enough for serious work. So despite a few shortcomings (which are typical for super-wide lenses) it definitely is not just a 122° toy to evoke a few ohs and ahs but a worthwhile tool.

However at 17 mm it is slightly inferior to the K-M 17-35, and at 24 mm it is clearly inferior. So it should be purchased for the 12 mm short end; the rest of the focal range unfortunately is not quite as useful as it could be.

-- Olaf

[Dr. Harout]

Thanks for this explanation, Olaf.

[David Kilpatrick]

I've been doing much the same comparison and would agree all round, except for adding that if you need just one lens the 12-24mm wins - and there are some important settings between 12 and 17mm which are impressive on the 12-24. I've used at least half a dozen Sigma 12-24mms over the years, and either the A900 is more compatible with the 12-24mm than any previous camera I have used, or my current (purchased!) 12-24mm is a really good example.

It's also worth pointing out that the 17-35mm D will take advantage of the f/2.8 focus sensor in the A900 at 17-20mm when it has a true f/2.8 available. The 12-24mm will never use this sensor. As a result, the 17-35mm may focus faster and more accurately than the 12-24mm when set to 17mm. This is a trade-off against the waveform distortion.

Finally, unless the 16-35mm f2.8 has been revised in a big way since the prototype, this lens has the same type of compound distortion as the 17-35mm, Canon 16-35mm etc. The Nikon 14-24mm is more like the Sigma and has a clean barrel distortion not a wave form at 14mm.

David

[David Kilpatrick]

Not a single Dxyum lens review has to use pictures. Olaf's description is technically sound and easily understood, and does the job rather better than posting bits of dozens or even hundreds of images would do.

I rather like Anders Uschold's lens reports - they, sensibly, include not a single photograph taken with any of the equipment other than some specific test targets.

David

[pakodominguez]

LOL...In-fact many lenses do have sample image threads linked from the review, and the MAJOR point I was making is that the people that review the lenses at Dyxum actually post pictures to threads at the VERY BUSY Dyxum photo forums. You must be new, eh? Olaf does not post anything but words, and the pictures I have seen of his pretty much suck. Technically speaking, the web photos of his I have seen are the worst I have ever seen anywhere, anytime, bar none. If the man can't make a web size photo I have ZERO confidence in any testing he does.
...
Olaf should at least post the samples...

-Sonolta

Don,
I would love to see those samples too. But...

You probably don't know Olaf enough. I have the chance to participated in a couple of other forums where he use(d) to share his knowledge. The Minolta and the ManualMinoltaFree Yahoo groups. These are groups where attachments are not permit and we just trust people because their expertise. Most of the knowledgeable people that you can find here, on Dyxum or DPR had been part of those Yahoo groups for a while before this (or Dyxum or DPR)forum layout kill them little by little. Brief: if Olaf said so, I just trust him (and he doesn't need me for defend himself)

There were another member that I specially like, Dave Saalsaa, who used to compare as many samples of a lens as he could -hunting for lenses on ebay, getting 4 or 5 samples of a Rokkor 50mm f 1.x in order to find the best of them and then, he compared it to a Summicron. I can only trust people like that.

Your Dyxum samples are "nice" but you cannot judge sharpness on a 800 px image, sharpened for the web! Can you? Not to tell about those people comparing un-comparable lenses (a zenitar!, a kit lens, a 28-75 or 28-70G)

Yeah, I wanna see samples too.

[pakodominguez]

Don,
I would love to see those samples too. But...

You probably don't know Olaf enough.

His advice sucks with regards to bokeh and macro...what more can I say.

you will never really know because some people, like Olaf, will never answer you...

I have the chance to participated in a couple of other forums where he use(d) to share his knowledge.

I have read Olaf in other forums...same story all talk and no pictures.

The Minolta and the ManualMinoltaFree Yahoo groups. These are groups where attachments are not permit and we just trust people because their expertise.

To trust Olaf would be stupid.

I know: If I wasn't stupid I'll be working in a way to make my first million dollars before the end of the month...

Now tell me why I should trust Olaf when he posts nothing for us to evaluate and the only thing we can find is his shoddy work like this:

http://www.ulrix.de/pferd/jagd/dkbl08/index_0007.html" onclick="window.open(this.href);return false;

http://www.ulrix.de/pferd/jagd/hchs07/index.html" onclick="window.open(this.href);return false;
-Sonolta

You are taken as samples of somebody's "work", pictures that haven't been meant for that.

In other hand, most of the link you post here are from other people experience -how do you know you can believe on those authors? You don't care. You use those articles just because they back your own toughs. But you never post authors that contrast your thoughts, probably because those are just plain stupid and they won't make a million before the end of the month...

This par of the discussion is over for me.

Regards

[Dusty]

I know: If I wasn't stupid I'll be working in a way to make my first million dollars before the end of the month...

Pako, I don't know what you're doing wrong, but I'm working on my 5th million. (I gave up on the other 4! )

Dusty

[Mike-Photos]

you will never really know because some people, like Olaf, will never answer you...

Olaf is nothing to me. As far as I know he is a clueless little fellow with no good pictures to show. He has me on his *foe* list because I have proved him wrong so many times already.

I know: If I wasn't stupid I'll be working in a way to make my first million dollars before the end of the month...

Why do you keep talking about end-of-the month? Do you have some fetish with the end of the month?

You are taken as samples of somebody's "work", pictures that haven't been meant for that.

LOL...The man must have no good work...if he does then show it to me.

In other hand, most of the link you post here are from other people experience -how do you know you can believe on those authors?

Most are from highly respected authors. Get a clue. Olaf must have no good pictures to show us. BTW....I have probably posted more images on here than the rest of you people combined.

You don't care. You use those articles just because they back your own toughs. But you never post authors that contrast your thoughts,

That's your job...it's called a discussion. Facts are facts and bullsnot is bullsnot.

probably because those are just plain stupid and they won't make a million before the end of the month...

What month are you talking about?

This par of the discussion is over for me.

Good...you are the foolish one that does not believe that of the gear scamhouses are/were located in NY.

Regards

When you find something good of Olaf's please do post the link here.

Until then please do refrain from defending his picturele$$ a$$ and let him try to cover his own rear.

-Sonolta

Hi Don
That's it for me. I've learned a lot from you, but some things are more valuable than knowledge. You are on my ignore list. Bye!

[David Kilpatrick]

Don, you are out of order. I know some internationally renowned technical experts who never took a decent picture in their lives. Taking impressive pictures has nothing to do with photographic technical know-how or skill. I worked for many years with editors like Andrew Mannheim whose pictures were so boring you would have cried, but who nevertheless were respected authors of Focal Press guides etc.

Olaf does not post here claiming to be an amazing photographer. He posts as someone with a very detailed (internal, mental, learned, not looked up via Google) knowledge of Minolta and Sony equipment. His personal knowledge of Minolta kit is better than mine, even though I have run the Minolta Club in the UK for nearly 30 years. I was never an equipment or tech-data nut, just a photographer and journalist, and I have a lot of respect for people like Olaf who have detailed knowledge of the system over a long time-span. Also, check the 'Wheels within Wheels' challenge and you will find a picture from Olaf which is at the top of the pile by any standards.

I have, as ever, received a number of private message requesting your immediate banning from this site DESPITE your valuable contributions - because you are so effing rude to people who do not deserve to be treated that way.

'Wad but the gift the giftie gie us, tae see oorselves as aithers see us!' - Robert Burns, 250 years in a week and a bit. Translated: 'If only God could give us the gift to see ourselves as others see us'.

I can not believe that you want to be seen as people see you. I have said before, and will repeat - Don Northup can be a hero, not a zero. It does not mean backing down on your opinions, or accepting defeat in arguments. It just means treating other people here with absolute courtesy and respect no matter what you think of them personally.

David

[David Kilpatrick]

Don, that is the closest I have ever seen from you to an apology.

I do not care what you think of me - if I am going to stand up here, then I stand up to be shot down, so be it. I do care about others.

I hope they also see your post as an apology (within your terms). Thanks!

Now let's get on with the REAL business of defending the America that Greenday don't like! I don't have the money but I'd love to promote a festival featuring:

Acoustic Chumbawamba
The Levellers
Greenday
Billy Bragg
Dick Gaughan
Peggy Seeger
Leonard Cohen

my political flavour, and I regret to admit that despite being a public-school educated capitalist and former Young Conservative, it's not right-wing. Clue: founder member of SDP and author of the election manifesto for SDP in Bassetlaw, the heart of resistance to M. Thatcher! Funny thing is that my election manifesto was so 'acceptable' the Conservative Party copied whole sections of it, including graphics, and got taken to court as a result...

But that was over 20 years ago. These days I just relax and play the music. Left or Right, they are only there to screw you regardless!

David



David

[caporip]

A900 + sigma 12-24 at 12mm f5.6

[Dr. Harout]

Nice one.