Qestion, replace battery in Vario-Switar 100 POE
Posted 09 January 2006 - 12:38 PM
Posted 09 January 2006 - 12:57 PM
Exists any experience to replace the battery Mallory PX-1 for the exposure meter in Vario-switar 100 POE, with the adaptor ( MR-50 Adaptor - Voltage Reducing Converter) and a silver oxide cell. http://www.smallbatt...r50_adapter.htm
You are better off using a handheld meter than trying to depend on the meter in the 100 POE lens. The issue is that mercury oxide batteries had a very unique discharge characteristic. The mercury oxide cell put out exactly 1.3 volts for the life of the battery till the very end, then it went to zero. This was the perfect situation for light meters made at that time because they were very dependent on a very constant voltage. So even though you can get batteries that will fit into your POE lens, their discharge characteristics will not be the same as mercury oxide, so your meter will work but it will not be accurate. Most batteries made today, and I am not certain about the silver oxide ones but I think this holds true for them as well, start out at a particular voltage, usually a little higher than they are rated at, and slowly decrease their voltage output as they wear down. For an old style light meter circuit designed for a very consistent 1.3 volt output, this makes the meter completely inaccurate.
Hope that make sense,
Posted 09 January 2006 - 03:42 PM