Am looking for some advice from the Bronica gurus. Just picked up an Etrsi w/a 75mm PE and a 150mm E and am having a great time learning to use it. Would like to get a 50mm wide angle to round out the lenses. I am wondering about all the variations in the lenses, i.e. mc, e, eII and pe. Are there were any problems common to them(esp. the older versions) I should look out for?