Strange behaviour of a Bronica 50mm MC lens

<p>About a year ago I had to buy a new (well, second hand of course) 50mm MC lens for my Bronica ETRSi. So after some searching I found a great deal on a mint lens, there wasn't even a scratch on it and it came with a 1 year warranty. All went well and the lens performed like it should. Winter approached and so did the cold, suddenly the lens won't fire correctly any more but once in a warm environment the lens behaves correctly again. The strange thing is that I noticed the same thing with my previous 50mm MC lens, might there be a design flaw in this particular lens that it malfunctions when cold?? When I put my 75mm PE lens on everything works like it should, even in the cold. Anybody had the same issue or knows why this only happens with this type of lens??</p>

<p>Possibly not a design flaw as such but a feature (or shortcoming) of the lubricant used.</p>

<p>Most likely the old lube needs to be replaced. If you take off the back you can reach the lube points on the actuators (the parts on the back which the camera body moves). The actuators must move very easily or the camera will not be able to move them.<br>

I had the problem with a 75mm lens and cleaning and light regreasing solved it completely.</p>

<p>They just may need a CLA. Old lube tends to gunk up over time. Also if the lenses have been sitting around for a long periods of time without use, they tend to bind.</p>

<p>Another thing to check is your battery condition. Older batteries get weak and will run the shutter at 1/500th when cold (dead battery default speed). Is the shutter running slow when cold or just firing at high speed?</p>

<p>50mm and other lenses all act the same in the cold, no special problems have ever been reported with any one in particular, design flaw is not an issue.</p>

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<p>Must be gunked up lubricant then, the other lenses function like they should so no battery issue.</p>