Using MD script to capture animals at night - Creative Uses of CHDK - CHDK Forum
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Using MD script to capture animals at night

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Offline Jose Viana

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Using MD script to capture animals at night
« on: 13 / August / 2008, 17:04:04 »
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Im trying to use the MD script to get pictures of some mammals during night. Till now I was not able to get the script working due to lack of light. Any ideas how to solve this? Does infra-red light will work with a A570 IS ?
Thanks for any help.
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Offline reyalp

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Re: Using MD script to capture animals at night
« Reply #1 on: 13 / August / 2008, 17:55:38 »
AFAIK all these cameras have an IR filter of some sort. You might still be able to do it with a bright enough IR light. People have also removed the filters, but it's not trivial and risks destroying the camera if you don't do it right.

If there is a little bit of light (stars, moonlight) you might be able to crank up the gain and exposure while doing MD (so that the display picks up movement) and then change it before taking the shot with the flash. If this works, you'll have to tune your MD options so noise doesn't set it off.
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Offline cybercom

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Re: Using MD script to capture animals at night
« Reply #2 on: 13 / August / 2008, 20:45:52 »
This might be totally off the wall, but:

If an IR light was shining directly into the lens, any animal passing between the light and the camera might cause the motion detect routine to trigger by its shadow and then the flash could illuminate the subject.

Comprende?
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Offline vk2him

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Re: Using MD script to capture animals at night
« Reply #3 on: 14 / August / 2008, 01:18:17 »
Quote from: cybercom on 13 / August / 2008, 20:45:52

If an IR light was shining directly into the lens, any animal passing between the light and the camera might cause the motion detect routine to trigger by its shadow and then the flash could illuminate the subject.

This assumes that the IR filter allows some light to pass ?? If it works it may only work over a very narrow window  :blink:
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Offline whoever

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Re: Using MD script to capture animals at night
« Reply #4 on: 14 / August / 2008, 03:43:19 »
Quote from: vk2him on 14 / August / 2008, 01:18:17
This assumes that the IR filter allows some light to pass ??

Just point your TV remote control at the camera and see for yourself. BTW a good method to check batteries in the remote.

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Offline mx3

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Re: Using MD script to capture animals at night
« Reply #5 on: 14 / August / 2008, 04:48:01 »
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Offline fudgey

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Re: Using MD script to capture animals at night
« Reply #6 on: 14 / August / 2008, 05:26:27 »
Yes the IR filter of course lets some light pass, there's no such thing as a perfect filter (especially not in the P&S price range). Just a few IR leds may not be enough for illumination, but can't know without trying. Cybecom's idea is worth trying unless bright spots from the lamps is out of the question.

Anyway, make sure your aperture is wide open while detecting and use zoom=1x to get the most light.

But why I really posted was this recent discovery by ewavr:
Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
I wonder if that works outside video recording for live view as well? That's what video (and MD) use after all, isn't it?
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Offline NewbieToobie

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Re: Using MD script to capture animals at night
« Reply #7 on: 14 / August / 2008, 06:10:02 »
Your best bet would be to use one of the Sony cameras with "Night Shot" mode in them. The F707, F717, F818, H9, or H50, there may be other models that also have it. They can take images in total darkness by IR light alone, or use the IR light for focusing and then fire the flash for full-color "Night Framing" mode. But they don't have motion-detection in them. You can even buy inexpensive (~$40) IR-LED flood-light add-ons for them to extend their IR photography range at night up to 50-80 feet, depending on how many that you use.

If it were me and I wanted to use a Canon Powershot with CHDK instead, I would buy some of those very inexpensive motion-detection yard-light fixtures in most any hardware store. The kind you put on your outside walls that turn on the light as soon as something moves within their range. Often sold as "security lights". Then modify the circuit to use batteries and trigger the camera by the USB remote feature of CHDK. Their sensitivity should cover the distance that can be reached by flash with the camera.

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Offline ewavr

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Re: Using MD script to capture animals at night
« Reply #8 on: 14 / August / 2008, 06:24:15 »
Quote from: fudgey on 14 / August / 2008, 05:26:27
But why I really posted was this recent discovery by ewavr:
Will Override Shutter/ISO or Aperture ever be enabled in Movie Mode?
I wonder if that works outside video recording for live view as well? That's what video (and MD) use after all, isn't it?

This works in live view mode, but with exposure with 1s and more camera can not detect quickly moving animals.
Maybe solution with PIR sensor is better, but works only with warm-blooded animals.
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Offline fudgey

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Re: Using MD script to capture animals at night
« Reply #9 on: 14 / August / 2008, 06:52:58 »
Quote from: NewbieToobie on 14 / August / 2008, 06:10:02
If it were me and I wanted to use a Canon Powershot with CHDK instead, I would buy some of those very inexpensive motion-detection yard-light fixtures in most any hardware store. The kind you put on your outside walls that turn on the light as soon as something moves within their range. Often sold as "security lights". Then modify the circuit to use batteries and trigger the camera by the USB remote feature of CHDK. Their sensitivity should cover the distance that can be reached by flash with the camera.

...or without any modifications to camera or detector hardware, just connect the security detector to an IR lamp instead of a regular lamp. Or use a regular lamp if the animals don't mind. The motion detector will notice the overall increase in luminance when the lamp switches on and triggers instantly.

A 12 V battery + inverter combination gives you portability.
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