I don't see an exposure lock button. Is it possible to set this up on one of the soft keys? Maybe the shutter release locks the exposure on half press but this usually also locks the AF which is not always desirable. I use the AE lock all the time on my LX3 (while pointing at something lighter or darker) which is much quicker than setting exposure compensation.
I guess this is no different from the earlier NEX models so if anyone has experience of this please share.