usb remote quick response

ozcar

13

Re: usb remote quick response

« Reply #20 on: 06 / June / 2015, 23:16:41 »

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I have had the camera back outside for some time now, but there has not been much action. Then, two nights ago a creature came past and triggered the camera (I can see what goes on from the video). The camera took a shot, but it is completely black - the flash did not go off! Of course, when I test it, the flash goes off every time (camera is set to always use the flash).

Since then the camera has been triggered a few more times. I even got one reasonable shot. I'm not sure yet, but I think I have a variation of the problem I had before, where the response got slower the longer the camera had been waiting. Now the response time does not increase, but I suspect the flash power is gradually reducing, and after a day or two the flash may not go off at all. I would have to do some very lengthy testing to prove that is what is really happening, but that is what it looks like from the few shots I have at this stage.

At a (very) wild guess maybe the flash charge slowly leaks away? Would the camera not "notice" that though? I see I could use get_flash_ready to try to check if the flash is "ready and charged", but if the camera somehow does not notice that the charge has leaked away, would that be likely to tell me anything useful?

I am wondering if the effect I am seeing (or I think I am seeing) could be a side effect of holding the shutter button "half-pressed" all the time while waiting to be triggered. I was thinking of releasing the half-press periodically, say every 30 or 60 minutes. while waiting for the trigger.

Any thoughts on this?

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waterwingz

12140

Re: usb remote quick response

« Reply #21 on: 06 / June / 2015, 23:52:01 »

Quote from: ozcar on 06 / June / 2015, 23:16:41

At a (very) wild guess maybe the flash charge slowly leaks away? Would the camera not "notice" that though?

I suppose it's possible. Don't forget that the Canon engineers never intended that these little camera do all the tricks that CHDK allow. So the idea of the camera sitting powered for hours with a full charged flash never occurred to them.

In fact, this would explain your increasing delays. As the flash discharges, it takes longer for the camera to charge it back up when it is finally asked to take a shot.

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I see I could use get_flash_ready to try to check if the flash is "ready and charged", but if the camera somehow does not notice that the charge has leaked away, would that be likely to tell me anything useful?

You would have to test it and see. But I suspect the same thing that you do - once it has fully charged once, it will report ready even if the charge has drained away.

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I am wondering if the effect I am seeing (or I think I am seeing) could be a side effect of holding the shutter button "half-pressed" all the time while waiting to be triggered.

I doubt it.

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I was thinking of releasing the half-press periodically, say every 30 or 60 minutes. while waiting for the trigger.

You could try that but as I said above, I don't think that's the problem.

But one thing you could try would be having your script take a wasted shot every 30 or 60 minutes. Might be annoying if you have to watch the flash go off all night but it would solve the recharge problem.

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Ported : A1200 SD940 G10 Powershot N G16

ozcar

13

Re: usb remote quick response

« Reply #22 on: 20 / June / 2015, 01:20:55 »

Another update report:

I have had the camera outside for a few weeks now since I made the last changes to the script.

I was not too keen on actually taking a shot periodically to try to avoid the problem of the flash gradually getting weaker the longer the camera had been waiting. So, I went with periodically releasing the half-press, and then immediately redoing the half-press. I set the interval to 60 minutes.

It looks like this does the trick. On several occasions the time between shots was two or three days, and the flash was not noticeably weaker. In that situation, before doing the release-repress thing, the flash might not go off at all.

Thanks to all who helped.

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