I recently got my hands on a beautiful ETRSi kit, and already on my 2nd trip out with it I managed to be out there in the wild using a camera equipped with a electronic shutter and a flat battery. Annoyed, I quickly got a new battery, but was still wondering how much power the ETRSi draws. So I got my trusty Tektronix DMM and the Radioshack probe kit and checked how hungry the ETRSi is. Turns out, not much. To make it easier, I put my readings into a little chart.
The camera used was a Zenza Bronica ETRSi with the Zenza Bronica ETR AE-II Finder and the Zenza Bronica Zenzanon-S 40mm F4 mounted. I checked if different light levels (cap on and exposed to a bright light) change the readings, and for most modes there was hardly any chance at all. Only in A-Mode the readings changed slightly with the light, so the values for A are averaged.
The average PX28 battery, like the ETRSi uses, has a capacity of 150 mAh. Checking the chart, that means if you leave your ETRSi with the meter set on A, it will suck the batter dry in about 300 hours – or 12 days. Worse, you you put it in your bag with something pressing the Display Button of the meter, it will draw over 30 mA – means you battery will be out in just 5 hours.
But the good news is, T mode draws no power at all – hello star trails. This will be fun.
So the two top tipps for every ETRSi user is:
1. Make sure your meter prism is turned off when you are done shooting
2. Get a waist level finder!