f2.8 is not everything. IMHO the ZD 14-54 is better. Esp in SG if service is considered.
that is also true. Sigma 18-50 is a little slow at focusing (understandable, being dubbed a macro lens), just slightly better than ZD 14-45 i had, both using
E520 body (PDAF), but it is mechanical MF so MF is imho, more tactile, unlike motor assisted focusing system in majority of ZD lenses. AF does hunt in low light/contrast occasionally which prompted me to upgrade to ZD 12-60.
strongly suggest you try your hands on both, then make your decision. i think the prices for both are quite similar. Have not personally tried the ZD 14-54, but it has a longer focal length range and possibily faster focus. Plus with your E-P1 body, you'd probably be better off with the ZD 14-54 Mk II which supports CDAF.
yes, F2.8 isn't everything, if you have to live with slow focusing speeds if the sigma isn't working fast with CDAF of PENs. (do correct me if i'm wrong)
thanks for the advice guys! also, i believe the sigma will be cheaper than oly's zuiko. just wondering if the constant f2.8 is worth it. or if the zuiko is even better than sigma even tho its not constant f2.8..
Also, what's your reason looking for a standard lens specifically with F2.8? lowlight shooting? imho, for lowlight shooting, you'll be much better off with an external flash (FL36/FL50).
tbh, personally i feel in lowlight, F2.8 helps, but it's really still not optically very fast. that's why i got an ext. flash.