Did a quick search and could not find much on this so here goes with essentially my first post in this FM forum.
I just bought an old Minolta AF200 2.8, that I can return, and in testing it on my Sony a77 found that one in seven or so shots would be drastically overexposed. I examined the lens closely and found it to be in good working order: no fungus, blemishes, nicks, etc. There was no sign of oil on the aperture blades, and the aperture snaps back just fine.
The only thing I could see was that the five gold contacts appear to be worn, a little bit of a shiny area across each of the five where the camera contacts would move across the lens contacts while attaching and taking off the lens. I carefully cleaned them really well, and the problem has not reappeared in probably 150 or so followup test shots.
So it seems ok for now, but -- what do you think -- could it be a real problem down the line, or am I making a mountain out of a molehill with this? It is a 22-year-old lens, after all, and, true to the classic reputation the lens has, it is very sharp. What do you think? Thanks in advance.
I'm no expert on this lens, but I think you are probably going to be ok...As long as the contacts are in good shape...not deformed or mutilated, cleaning should do the trick. A pencil eraser is a pretty good and popular way to clean electrical contacts. Abrasive enough to clean, but won't scratch or do damage to the plating. All contacts will get dirty eventually requiring cleaning. If the contacts *are* damaged in some way, or deformed so that they do not actually contact the pins in the body reliably, then that would be a different story. Hope that helps and I'm sure others will chime in with their thoughts.
Thanks for the pencil eraser idea. I would certainly never have thought of that. I am sure, though, that don't have any pencils anymore. It's a good excuse to get a couple, I guess.
DO NOT USE A PINK ERASER. the ones on the end of a pencil have an abrasive in them and it is abrasive enough to remove material. this can/will scratch and remove the gold/anti corrosion coating from the contacts. this can/will possibly cause faster contact failure which will cause you to do it more. a qtip w/alcohol or methenal will do it to without ripping things up. just rub your pink eraser against a tooth and see how it feels.
