OT: Cameras, cameras, cameras.. (was Re: Lightbulb police? ...)

My experience with digital cameras that operate on AA batteries is that the problem is not so much self-discharge as it is poor design. (This is also true of many other products) They design the cameras to run on AA batteries - marketing says it has to shutdown gracefully when the batteries run out - and they design a low battery threshold based on 1.5v AA alkaline batteries. Then when they realize it hogs so much power it only takes 3 shots on dry cells, they spec. high capacity NiMh cells - which are nominal 1.2v per cell. I have tested: Minolta Dimage 7Hi - recommended to use NiMh cells (set came with it), takes 4 cells (nominal 4.8v), measured low battery threshold is about 5.2v. Two Cannon A520s - recommended to use NiMh cells, takes 2 cells (nominal 2.4v), measured low battery threshold is about 2.6v. Hp M(something or other - it's gone now) - recommended to use NiMh cells, takes 2 cells (nominal 2.4v), measured low battery threshold is about 2.7v. Sony F42 flash - takes 4 cells (nominal 4.8v), measured low battery threshold is about 5.1v. Both the Dimage and the A520 were reviewed to have "excellent battery life" - the reviews say you can charge a set of cells, and then shoot "all day". Which is mostly true. However when you turn it on a morning or two later, after the cells have settled down to their nominal 1.2v level, they shut down saying the batteries need to be replaced. In fact this happens even if you didn't shoot anything - just install freshly charged cells and wait a couple of days. But... I can take the "dead" cells out of the cameras, and put them in my 2m handheld - a fairly high current draw device when transmitting, and they will run it for weeks. I tested once taking the "dead" cells nearly 10 hours - ie: nearly the full capacity of the cells. NiMh calls when freshly charged exhibit 1.3-1.4v/cell, however they settle fairly quickly to 1.2v - even if not being used... then the voltage remains is nearly flat until the cells are depleted, at which point they drop rapidly. Long term shelf life is poor due to self-discharge, however in my experience your camera will reject them long before this should be a factor. Self-discharge takes months, not days. Hybrid cells like eneloop help with self-discharge, and do slow the initial drop which makes them more useable in a camera ... but the fundamental problem remains - the device simply was not designed for 1.2v cells and shuts itself off when it things the "standard batteries" are getting low. When my A520 says to replace the eneloops, they are still just at the top of their discharge curve. Slight relevence to old computers: Most of the photos on my site were taken with the Dimage (it's very good in indoor low-light conditions - I got it free because the original owner "couldn't keep it in batteries")... I struggled for a while charging batteries every session, but since most of my photos are taken at a single location, it was easy to provide a power supply and it hasn't caused me any trouble since. -- dave09 (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Classic Computers: http://www.classiccmp.org/dunfield/