On Sat, 06 Dec 2008 01:14:07 GMT, John Doe wrote:
>> I'd also tend to suspect that this is a factor. My wife's fairly
>> recent point&shoot cameras have a three-way adjustment for the
>> battery voltage -
>
> Are you talking about a "switch" or do you know what's going on
> inside of the camera?
Cameras almost always implement battery "switches" via menu
options.
>> for NiCd/NiMH, alkaline, and lithium-primary cells. Setting it
>> properly makes a big difference in the camera's willingness to use
>> the batteries.
>
> Same question as above. Looks like you are talking about what's
> going on inside of the camera, but I doubt it.
Same answer as above.
>> If left on the "alkaline" setting, and loaded with freshly-charged
>> high-quality NiMH cells, the camera will (mistakenly) report
>> low-battery after only a few flash photos when the cell voltage
>> drops below around 1.3 volts. The cells still have oodles of
>> charge, but the camera mistakenly believes that they're alkalines
>> on their last gasp of power.
>
> And what happens? Does the camera stopped working?
>
> You are looking at an incorrectly adjusted voltage level indicator
> (when you use rechargeables but don't correctly set the camera).
> That is meant for you the user, it should not affect operation of
> the camera.
If well designed it *will* affect the operation of the camera.
Some old cameras probably had "dumb" battery warning indicators,
relying only on observant users to power off the camera and swap
batteries. But that was then, and now it's different for most
cameras. Battery voltages fluctuate with usage, dipping more when
zooming the lens, focusing, writing to memory cards and especially
when recharging the flash's capacitors. Cameras can perform many
different types of operations when the batteries are fairly close to
the minimum operating voltage (a range, not really a point, due to
component tolerances). This is the point where a well designed
camera will shut down, because at this point if one more picture is
taken, there may not be enough energy left in the batteries to
complete saving the picture to the memory card, and this could trash
the card, even though many other operations could still be safely
performed, such as changing menu options, changing shutter speeds
and f/stops, even reviewing previously taken images.
Other devices also intelligently shut down at different voltages.
Many PDAs not only let you specify the battery type used, they also
have utilities that let the user redefine the voltage points where
battery warnings are given, as well as what voltage level initiates
the shutdown of the PDA. I'll leave this as an exercise for the
authors of the CHDK hack to implement - assuming of course that they
haven't already done so.