Originally posted by Aristophanes Sigma's secret is very large glass.
The 18-35 and the new 50mm are enormous lenses. The Art 50 is 810 g and 99.9mm x 85.4mm. The DA*55 is 375 g and 70.5 x 66mm.
Sigma is pulling a Zeiss with AF. Their marketing strategy is test results and not real world practicality. Sigma prices well because they can jump mounts. Good glass but HUGE.
I am sure this rumoured 24mm will also be a monster.
I don't think this is the only secret but it is certainly part of the story. After all, Sigma lenses always have been abt if not quite a bit bigger than OEM comparable lenses.
They aren't alone though, Samyang does pretty much the same and I think lately Samyang and Sigma will effectively compete directly with each other.
That's probably why:
* Samyang canceled their 50mm projects.
* Samyang seems to be interested in AF lenses.
If Samyang wanted to sell a manual focus 50/1.4 at about 800 dollars/Euros, they'd be killed instantly by the Sigma.
And yes, the 24Art will be huge, of course it will.
---------- Post added 23-04-14 at 17:41 ----------
Originally posted by Winder I tried 2 DA* 55mm lenses before going with the Sigma. Coming over from Canon I had always avoided Sigma because of AF issues. I was using the K-7 at the time, and neither of the DA* 55mm lenses I bought could AF consistently enough to make it through the first week. The Sigma had faster and actually more accurate AF and was sharper from F/1.4 to F/4.0. I really wish Pentax would improve this lens. I want a weather sealed lens in this focal length, and currently that is my only option.
Well, this isn't surprising since the 55/1.4 was/is (pick the one you fancy) destined to be a portrait lens and the Sigma is clearly optimized for sharpness.
(not counting the SDM thingie which is veryreal though).