Can a script blank the display? A590IS

peabody

Re: Can a script blank the display? A590IS

« Reply #20 on: 14 / March / 2009, 17:55:46 »

Advertisements

I want to report the results of the timelapse test I did this morning.

The camera is an A590IS, firmware 1.01b, CHDK version 719. The batteries are new Eneloops which have been full-cycled three times, the most recent cycle being three days ago. All unneeded functions (IS, etc) were turned off, and the test was run with the display turned off, and with aflock used to fix the focus. The camera was in M mode. The picture interval was set to be a nominal 4 seconds, but actually averaged 4.6 seconds. The memory card is a 4GB SDHC.

Well, it kept going like the Energizer (Eneloop?) Bunny, and I finally ran out of time and had to shut down the test. At that point, it had run for 3 hours 26 minutes, and had taken 2,679 pictures. These were 1600x1200 Superfine. When I switched the display back on, the battery voltage settled down to 2.512V. I think this means there was still plenty of juice left in them, and the test would have continued for a few hours more, or until the card filled up. My camera shuts down at around 2.2V.

It seems pretty clear that it's the display that uses up batteries, not taking pictures. Well, the display and maybe other things like histograms, IS, and so forth.

There are two things that bother me a bit about the test. The first is that the camera makes a good bit of mechanical noise if you listen closely, and my previous experience is that MF mode eliminates most of this. So I'm going to give that a try, with a plug inserted in the AV port, to see if I can minimize the wear and tear. If battery life is even half this good under MF, that would be plenty good enough.

The second problem is that even though everything was completely fixed - focus (via aflock), shutter, aperture, ISO and white balance, the pictures vary somewhat in brightness, which is a bit disconcerting when speeded up in timelapse. I HOPE this is because the pictures were taken in fluorescent light, which has flicker. If not, then my camera may not be up to this task.

The video is at this site, but you'll have to download it to view it. Just right click on the icon. Divx codec. It's just a jar of melting ice with an electric clock next to the jar:

http://drop.io/dvts5vq

In terms of battery life, this test was far more favorable than I expected. I think it means with the right preparation you should be able to do quite lengthy sequences on one set of batteries. Now I need to find out how much much difference MF makes.

Logged

fudgey

1705
a570is

Re: Can a script blank the display? A590IS

« Reply #21 on: 15 / March / 2009, 10:14:44 »

Quote from: peabody on 14 / March / 2009, 17:55:46

It seems pretty clear that it's the display that uses up batteries, not taking pictures. Well, the display and maybe other things like histograms, IS, and so forth.

The LCD itself probably takes up next to nothing. Backlight power is significant but not a huge deal (15% of idle rec mode total power input on a570is). I believe the sensor and whatever else shuts down with the display button shutdown is the most important part here.

Quote from: peabody on 14 / March / 2009, 17:55:46

The second problem is that even though everything was completely fixed - focus (via aflock), shutter, aperture, ISO and white balance, the pictures vary somewhat in brightness, which is a bit disconcerting when speeded up in timelapse. I HOPE this is because the pictures were taken in fluorescent light, which has flicker. If not, then my camera may not be up to this task.

What was your shutter speed? If you're shooting under 50 Hz or 60 Hz lights with a too fast shutter, you can indeed get flicker as you've experienced. Your camera should be fine for the job. The only little thing is that fixed white balance is not actually completely fixed, there's some fine tuning involved with Canon's presets. Manual/custom WB is the only really fixed one. But that shouldn't affect brightness, really, and I haven't noticed any flicker from that while shooting timelapses.

Logged

peabody

Re: Can a script blank the display? A590IS

« Reply #22 on: 15 / March / 2009, 16:58:16 »

Yes, custom WB is what I was using. But today I did another test with incandescent light, and there was no flicker. So it must have been the fluorescents. I'll try to remember that for future reference.

So today I did another test in M mode, but this time instead of leaving autofocus on and turning off the display, I went with Manual Focus and left the display on, but inserted a plug into the AV jack. This reduced the mechanical noise somewhat, but some was still left. I'm curious what this is. Does the A590 actually have a mechanical shutter? If so, that would explain it. Otherwise, I don't know what the camera would need to do physically, since absolutely everything is locked down - WB, ISO, T, A, and focus.

Today the camera shut down due to battery power after 3:23 and 2207 pictures. Even though the nominal setting was still 4 seconds, the average interval was actually 5.52 seconds, vs 4.6 sec. yesterday.

So even with the plug inserted in AV, this method clearly uses a lot more power than just turning the display off. But you know, it's still a bunch of pictures on one set of batteries. I had figured I would need to change batteries every hour, but it's an awful lot better than that.

I guess the only other option to test would be turning off the backlight, with no AV plug. But as I understand it, the light is still going to come on for a while after each picture. If that's the case, it wouldn't work for my current project bacause those flashes would be distracting. But I suppose in theory it might use less power that way since the AV drivers could be off.

I keep seeing posts about how much CHDK uses up batteries in this model camera. I can't say because I've never used the camera without CHDK. But it seems to me that turning off stuff you don't really need or use would make a big difference - such as continuous histograms and such. And as far as I can tell, Eneloops work really well too.

Logged

fudgey

1705
a570is

Re: Can a script blank the display? A590IS

« Reply #23 on: 16 / March / 2009, 17:12:29 »

Quote from: peabody on 15 / March / 2009, 16:58:16

I guess the only other option to test would be turning off the backlight, with no AV plug. But as I understand it, the light is still going to come on for a while after each picture. If that's the case, it wouldn't work for my current project bacause those flashes would be distracting. But I suppose in theory it might use less power that way since the AV drivers could be off.

One can always cover the LCD if its backlight flashing on and off is a distraction...but with your short timelapse delay the AV plug method will probably perform quite equally in comparison to turning off the backlight because the backlight indeed does pop right back on whenever you shoot and it takes a little while after the shot for the camera to settle before you can turn it back off again successfully.

The AV driver only requires about 60 mW of power compared to 200 mW for the backlight on my a570is, so to match the gain from the AV plug method (140 mW away from a total idle non-half-shoot REC mode power consumption of about 1.33 W with display and backlight enabled) you'd have to have the backlight disabled for 70 % of the time.

Logged