I'm shopping for a used 1 degree spot meter for film photography. There seem to be a lot available with a tremendous price range. Does anyone have suggestions for how to pick one? How much trouble would an analog model be as they're the cheapest.
I recently purchased a used spot meter. I limited myself to older (cheaper) models. This is my take:
The primary difference is between [selenium], (https://en.wikipedia.org/wiki/Selenium_meter), cadmium sulfide photoresistor and a silicon photo diode sensor. Selenium light sensors do not require electric current to measure light intensity.
Digital versus Analog
The digital lightmeters tend to display the light level on a numeric display rather than using a moving needle.
Older analog spotmeters with CdS photoresisters often were designed to use batteries containing mercury. These are no longer manufactured. There are direct replacements for some of the older batteries. For others there may be a new battery that mostly works but there are "reports on the internet" of voltage differences between the original design and what is currently available affecting meter readings on some meters.
The digital spotmeters tend to be designed to use alkaline batteries due to their more recent manufacture and the specific batteries tend to be readily available at the correct voltage.
While some digital spotmeters like the Minolta Spotmeter M and F have additional integrated circuits with memory and averaging, other digital spotmeters like the Pentax Digital use the same mechanical dial technologies as older analog spot meters.
For me, user interface was the deciding factor. I wanted the "ergonomics" a dedicated device can provide versus the spot metering function built into my DSLR...e.g. reading out in Light Levels versus a combination of ISO, Aperture and Speed.
I wanted a dial so I could see multiple options at a glance and think in terms of the zone system. I did not really want to enter values using little buttons as is the case with the Minolta's and did not want to worry about the additional mechanical and electronic components starting to go bad.