Zenit Automat: New but with a Strange light meter

[Gero Giambrone]

I bought a 1991 Zenit Automat a month ago. It looked new and in excellent condition, but the light meter behaves strangely: when checking with an external light meter or in a bright environment, the aperture-shutter ratio is correct, but in low light it overexposes by a stop. Sure, I can use the correction dial, but it's not convenient because I have to judge the lighting conditions myself. I've seen how to disassemble it in some YouTube videos: perhaps there's a potentiometer I can adjust for low light?

 

[runswithsizzers]

The Internet says that camera should have four PX625 batteries (mercury) -- which are no longer available.

What batteries are you using in it?

 

[Gero Giambrone]

First of all, thank you for your reply and for the helpful comments you made. Along with the camera, I found two new 4LR44 batteries (6v) from the previous owner, and I thought they were fine. You're right; I see online that this camera used 4 PX 625 1.35V batteries, for a total of 5.4V. The 1989 manual lists Soviet RC-53 1.25V batteries, for a total of 5V. A difference of just 1V could cause the light meter to malfunction! I'm looking for solutions: aside from the MR-9 adapter, which is too expensive (you need four), do you know of any alternatives?

 

[4season]

1.25 volt is likely a typo: The voltage is determined by the battery's chemistry.

Are your meter readings being influenced by light entering the camera's eyepiece? I've noticed that KMZ-made Zenit cameras can be particularly susceptible to this, including cameras made as late as 2005.