which 10-20 - if at all?

Must be something personal, but it's true that I use most of my zoom also at each focal ends...

Yeah I must admit I almost always shoot at 10mm with mine. I could probably count on one hand the number of times I've shot at 20mm. I didn't pay £400 for a 20mm f5.6 lens

I didn't pay £400 for a 10mm lens

I was lucky and paid £300 which made a less hard decision.

I tried using it as a street lens at 20 but it's way big.

I bought one of the original Sigma F4-5.6 EX DC 10-20s almost two years ago, and I've been very pleased with it. However, some have had difficulties getting a good copy, so a little caution may be warranted.

I've never wished it was any faster, and the extra 2mm at the wide end compared with the 12-24s is quite noticeable. There is significant barrelling at 10mm, which can be removed in software these days, of course, and goes away by 12mm.

At the time, it was only about £300 IIRC, which was a lot less than the Pentax 12-24. It was an obvious choice for me at the time, and I haven't regretted it.

With the price rises since then, and the availability of the other extreme wide angle zooms that have appeared since then, and the Samsung 12-24 being a lot cheaper than the ludicrous price of the Pentax one, the choice isn't so obvious any more.

I'd try and handle a couple of the alternatives if you can, especially if you have no experience of anything wider than 16mm.

over on Pentaxforums.com you will find thread full of pics by a lot of folks owning Sigma 10-20 (mostly 1st ver). link
I'm one of them... Have had this lens since winter 2007. And I never thought of swapping it for DA12-24.
10mm is just great! It's hard to make pics with it if you don't know how to deal with the aspects of ultra wide angle photography.
Most of my shots with this lens are at 10mm and very rarely the lens goes over 14mm.
The DA12-24 may be superb lens but at roughly the half price for the 4-5.6 version you can't go wrong with Sigma IMO.

Ajbets - I'm in Surrey too and I just bought the old sigma 10-20. If you want to meet up you're welcome to have a play with it to see what you think

Re the Samsung 12-24mm... I just spotted What Digital Camera have reviewed both this lens and, more recently, the Pentax version.

Pentax score: 91%
Comment - "Real-world pictures are very sharp and do not suffer from any obvious colour fringes."

Samsung score: 84%
Comment - "Lack of critical sharpness, fringing at corners"

:::

Either we are all wrong and these are two different lens designs, or What Digital Camera reviews should be taken with more than a pinch of salt. To be honest, that Samsung review - the only one I could find on the net - put me off buying one in the Currys free for all last year

That is interesting. If you put the Pentax and the Samsung side by side they look absolutely the same. It is very difficult to believe that Samsung and Pentax would make two different lenses, but for some reason decide to make them look exactly the same
Would not make much sense...

Coatings?

I had a Sigma 10-20 when I had an olympus, but of course with the 2x crop factor it's not the same as on a Pentax. However, it was my favourite lens, pobably accounting for more than half the shots I took, most of them at the wide end. I loved it, and can't wait to get another!

"Re the Samsung 12-24mm... I just spotted What Digital Camera have reviewed both this lens and, more recently, the Pentax version.

Pentax score: 91%
Comment - "Real-world pictures are very sharp and do not suffer from any obvious colour fringes."

Samsung score: 84%
Comment - "Lack of critical sharpness, fringing at corners"

....I am sorry, but you really, really cannot compare lenses using a horribly over simplified percentage score system from some dubious magazine.

Virtually all lens tests are dodgy at best. Most use far too simplistic testing methology and only use ONE example of each lens...this is a statistically speaking, very shoddy testing regime which cannot throw up any meaningful result and does not bear close scrutiny.

Everyone glosses over, or conveniently forgets that the small differences between lenses can be differences between samples, or can be impossible to see in real world useage and that of FAR more importance is the ability of the photographer to use the lens to its best advantage....give a shooter with average technical ablity a host of Leica lenses and you will still see average results...

Well Steve, "sorry but" the point I was making was precisely how unreliable that magazine turned out to be!

I agree on your second point too, but of course there are differences between lenses, and you might as well spend your hard earned cash on the one that performs best for the money.

"you might as well spend your hard earned cash on the one that performs best for the money"

...why? if you cannot see any real world difference? ..and who is a realiable person to say which is 'best' anyway?

My real point is that far too many shooters spend far too much time agonising on forums as to which is the 'best' lens...thats like saying which are the best tyres for my car? ...

....there are lots of different ones, but any mass produced item, be it lens, tyre or whatever is made/designed with many compromises, as they have to design/build down to a specific price point. There is no such thing as the 'best' lens...not at any price point...only differing lenses with differing sets of pros & cons...

cheers Steve.

I regularly use the Sigma 10-20 f4/f5.6 on my Pentax K20. I am very happy with it's performance and often set it at 10mm. The industrial photos in my portfolio were taken with this lens at 10mm.

And great photos they are too, Graham. That Sigma lens is beginning to exert a draw on me now!