I have a major problem with battery usage on my RX10 iii.

Sony brand batteries last about 250 shots at best with constant drainage even when switched off. Basically take a few pics and battery lasts no longer than 3-4 hours even when no shots taken.

I have 2 batteries and they're both the same so its not the battery thats at fault.

|Also have off brand battery, lasted 20 shots!!!

Any advice please. Have been told a firmware update may help, mines version1.0 but i can't find how to perform this update anywhere.