Haze in the front group seems to be common on the 2.8 Elmars, but it is fairly easy to care of.
The fingers that lock the lens in the taking position can weaken and unlock when the aperture is selected, but that is dangerously but quickly corrected by someone who knows.
What bothers me most is the weight of the collapsible portion makes it fall open easily, and I don't know if that condition is able to be corrected.
These conditions sure make the 3.5 Elmar look superior, if not correct for a IIIg.