Sigma 30mm and Sony 35mm F1.4 doesn't seems to have good feedback on their sharpness but it still good for portrait and all-round use for the expensive options

30mm is not that wide (probably ur using FF then it is  ).
get the 20mm f/2.8 or wait for the CZ24mm f/2  <---- this one even tapaw the great cz2470 

what do u want? if wide angle the carl zeiss or tammy is the best lor.

if UWA maybe u can get tokina ?

sell of your baby zeiss <= RM1.8-2k
buy the 16mm f/2.8 pancake lens get free NEX3 

joking 
got not so good review on  kenrockwell (http://www.kenrockwell.com/sigma/30mm-f14.htm)
quote from kenrockwell

Seng_Kiat: Long time no see! Yes the Sigma 30mm F1.4 is good. No, E-mount lenses cannot be fitted on A-mount dSLRs.

Seng_Kiat: I would just tell you to go to the shop and try it. The Sigma 30mm F1.4, like the Sigma 50mm F1.4 HSM, has a very different look.

Don't expect the pictures to look like your Zeiss. It is not a bad thing... but it looks different. If you stopped both down to F5.6 you could probably tell the difference by just looking at the color.

They are still nice and sharp especially in the center, but there is a certain... plasticky look about the colors. It is well saturated though.

I have not owned either lens, though.

dude, u cant compare normal monitors with Apple's ranges of monitors...

then why not might as well you go get the Apple?

Seng_Kiat: Go get a Spyder then. I don't remember which but there is one budget model. Even Apple monitors are not perfectly calibrated as my studio photographer friend notes. Monitors need to be recalibrated every month for optimum color work (though, it won't run much if you don't... but if your work is a critical science of color then you'd do so.)