Lithium batteries will work to lower temperatures than alkalines. There's a
form/fit/function-compatible 6V lithium that'll work in the Pentax digital
spot meter so that could help with your Zone VI problem if your version is
the one based on the Pentax digital. I have lithiums in my Pentax digital
and in my Mamiya 7, which takes the same battery type, and have never had
an issue. I can't speak to the Reveni meter or the Zone VI meters based on
the Pentax analog or Soligor spot meters.
Another idea is a remote cold battery adapter like the one Mamiya made for
the 6 and 7 series. The battery stays in your pocket and a wire snakes out
one of your sleeves to a 2.5mm connector. The other piece of the adapter
screws in to the Mamiya battery compartment and has a short pigtail with
the opposite-sex 2.5mm connector. Plug together for use. Sadly, the
Mamiya adapter won't screw in to the Pentax digital meter, and even if it
did the polarities are opposite - I just checked :(
Steve
Tim writes: "I will say that this has gotten me shooting 4x5 very actively
again because of the
joy of discovery. When I got up this morning, it was -6F. By noon, I was
trudging
through
calf-deep snow in a forest by a river with a full backpack on and a tripod
in my hand.
It was a balmy 0F at that point. Both my Zone VI and new Reveni Labs
meter (or their
batteries) conked out in that weather, even though both were inside a
jacket pocket
