Motion Detect and power saving in low light (Missing cat!)

[ColinWarhurst]

Hi all,

I've searched the forum, and I suspect there is no magic answer or I am missing something obvious, but I was wondering about best ways to save power using the Motion Detect feature.

Our 3-legged house cat has gone missing (Denton, Manchester, UK) and so we're leaving food out each night and trying to snap which local animals are eating the treats. I tried motion detect on night #01, but had to put H1 ISO in as my long lens (from upstairs in house) only went to f4.0 at the required focal length.

The feature worked well, but due to LV mode the battery only lasted a few hours, not the whole night. I suspect due to the high ISO, I was draining more juice. I also noticed that the sensitvity would "creep up" and trigger pictures over time. e.g. sensitivity 15 would be ok as the scene would read as 13, but after 10 minutes on high ISO the scene would creep up to 14 and eventually 15, thus triggering pictures unnecessarily.

So here is my question; can the camera use the LV data, but 'switch the screen off?'

I dimmed the screen and turned off all displays to get the most out of my battery.
Short of this and buying a mains adapter, are there any other tips for power conservation, and/or stopping the sensitivity of the ISO triggering pics.
Don't get me wrong, I'm not expecting any magical answers! Perhaps I am pushing this feature to it's limit (and need faster lenses or a little more light outside without scaring the cats away...)

It's an awesome feature as it is (I got better results than using time-lapse on night #02) but if anyone has any tips of knows or any extra MD features in the newer builds that would be awesome. Just want to catch evidence that our cat is still ok if we can...

Thanks again Team ML, Col

[dmilligan]

I've searched the forum, and I suspect there is no magic answer or I am missing something obvious, but I was wondering about best ways to save power using the Motion Detect feature.

Did you try reading the manual: http://wiki.magiclantern.fm/userguide#powersave_in_liveview

Also AFAIK the ISO doesn't really have much to do with power drain. It's the fact that LV is on, which is going to heat up the sensor, which in turn affects the sensitivity of the sensor (sensors work much better when they're cool).  You are going to experience almost exactly the same thing even at ISO 100.  So maybe you could turn the camera on for a little bit to let it heat up and reach equilibrium, then start the motion detect.

Also, as long as you're shooting raw picture quality, using an ISO above 1600 on most cameras (some higher end actually do 3200 or 6400 native) is pointless. The high ISOs are just digital and is no different from turning up the exposure in post.

Sounds to me like you might want to consider getting an AC adapter.

[RedHerring]

I would buy a cheap game camera to place by the food dish. I am sure you will get all sorts of interesting video.