Just wanted to clear some things up about getting consistent and accurate metering with cameras and light meters that have no built-in voltage regulators and relied solely on the stable (now banned) MR9 mercury battery output.
There are 2 problems sporting such cameras and light meters with today's MR9 equivalents:
1) different voltage: 1.55 instead of required 1.35V - this will give inaccurate readings. To correct it, one must install voltage dropping PCB or use MR-9 adapter.
2) for stable voltage alkaline won't cut it - its output isn't stable over its lifetime and range of temperatures and lighting intensity - silver oxide batteries must therefore be used, they are stable.
For people that want it neat and tidy I recommend going the MR-9 adapter (with integrated voltage drop feature) route that mimics the shape of the banned MR9 battery, fitting nicely in battery compartment. Pair it with silver oxide cell and you're golden!
I use this for about 10 years with OM-1 and OM-1n, and have no problems: exposures accurate for slides, battery lasts many years. And the end of battery is signaled clearly: sudden inaccurate readings. Replace the cheap silver cell and roll on for many more years. And silver batteries usually don't leak - another bonus!
Another route is to:
- install said voltage dropping circuit. Downsides: 1) opening the camera required and soldering involved; 2) you must fit different form-factor silver oxide battery in the battery compartment which can get ugly and unreliable fast;
- use hearing aid batteries - I'd avoid this although their output is stable and close to the MR9. Because of a simple downside: they last for a limited number of weeks draining themselves regardless if you use your camera or not. Creating perfectly avoidable waste in the process. And the battery compartment shape problem persists.
//Post made because even camera technicians tend not to be aware of this - especially of output stability of alkaline Vs silver oxide batteries.
There are 2 problems sporting such cameras and light meters with today's MR9 equivalents:
1) different voltage: 1.55 instead of required 1.35V - this will give inaccurate readings. To correct it, one must install voltage dropping PCB or use MR-9 adapter.
2) for stable voltage alkaline won't cut it - its output isn't stable over its lifetime and range of temperatures and lighting intensity - silver oxide batteries must therefore be used, they are stable.
For people that want it neat and tidy I recommend going the MR-9 adapter (with integrated voltage drop feature) route that mimics the shape of the banned MR9 battery, fitting nicely in battery compartment. Pair it with silver oxide cell and you're golden!
I use this for about 10 years with OM-1 and OM-1n, and have no problems: exposures accurate for slides, battery lasts many years. And the end of battery is signaled clearly: sudden inaccurate readings. Replace the cheap silver cell and roll on for many more years. And silver batteries usually don't leak - another bonus!
Another route is to:
- install said voltage dropping circuit. Downsides: 1) opening the camera required and soldering involved; 2) you must fit different form-factor silver oxide battery in the battery compartment which can get ugly and unreliable fast;
- use hearing aid batteries - I'd avoid this although their output is stable and close to the MR9. Because of a simple downside: they last for a limited number of weeks draining themselves regardless if you use your camera or not. Creating perfectly avoidable waste in the process. And the battery compartment shape problem persists.
//Post made because even camera technicians tend not to be aware of this - especially of output stability of alkaline Vs silver oxide batteries.
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