So MeFi, what do I need to know to bottle lightning?

January 29, 2010 10:05 PM

Help me photograph lightning.

My new phone has a camera; this is my first digital camera and I'd like to make some pictures to impress friends and family. I know the 5MP doesn't make it the best camera in the world but I'm satisfied with results thus far and it's very hackable.

This is important because I'm pretty sure I'll never get a good picture by reflex. What I'd like to do is build a sensor-trigger like this guy did. I own an Arduino Mega, and even picked up this IR sensor. But in order to do that, I want to some facts, figures, and insights.

What I'd like to do is gather a lot of information about the photographic properties of lightning. Duration, emission spectrum, and things I haven't considered. I have an IR sensor but parts are cheap if something else is better / faster. There's an FM tuner app that relies on the headphone jack; I'm somewhat curious if something similar can be done due to EMP.

I'm also not sure about digital camera considerations, hardware or software. gdigicam has an adjustable exposure but is unitless, and there's a ISO sensitivity level that is ambiguous to me but I assume is related to film ratings. I've figured out how to operate the autofocus feature after botching a dozen document captures, but its not likely to be of much use in this endeavor. If necessary I can probably figure out how to make a custom gstreamer pipeline and use dbus for automation.

So MeFi, what do I need to know to bottle lightning?

posted by pwnguin to media & arts (5 answers total)

Generally, lightning is actually quite easy to photograph. Open the shutter... hope lightning strikes while you have the shutter open, and in the frame. Set aperture / shutter speed/ sensitivity (ISO) for surrounding light. Play with it a bit, but you will get a nice shot after some practice.

I have no idea if you can set shutter speed / aperture with your phone camera.

ISO rating for digital is simply a sensitivity. The higher the number, the more sensitive (less light) is required, but the tradeoff is much higher gain (higher amplification - more noise). I'm going to guess that the phone may be 5MP, but the sensor will be wee small, and the noise will be high even on low ISO settings - so keep that low. You don't need high sensitivity for the lightning anyway, it's bright!
posted by defcom1 at 10:14 PM on January 29, 2010

Yeah, exactly as above.

If you go somewhere really dark (a cornfield) it's a lot easier because you can set the shutter speed for longer without getting an overexposed picture. If you can leave the shutter open for, say, 4+ seconds you're a lot more likely to get a picture of lightning. The ISO, well, that way lies noise (sort of like graininess, not really what you want in a lightning photo).

The best way to figure out when lightning is going to happen is to wait for thunderstorms and be ready to go photograph. Take a lot of batteries/memory (not sure how that applies with your phone).

I doubt you can adjust the aperture so shutter speed and persistence will probably be the way to go.
posted by kathrineg at 10:31 PM on January 29, 2010

I don't think building an IR trigger will work for a camera-phone. The lag time between pushing the shutter button and actually shooting the picture is typically really long on camera phones. YMMV
posted by gregr at 10:41 PM on January 29, 2010

The chdk open firmware for Canon cameras has some resources on photographing lightning. Look for ideas there.
posted by Pronoiac at 3:59 AM on January 30, 2010

Seconding CHDK.

Here is a lightning script that works:

////////////////////////////////////////////////////////////////

rem Author ~Keoeeit~
rem Written for S-series cameras
rem Should work okay on others

@title Lightning Photos
@param a Duration Minutes
@default a 1
@param b Duration Seconds
@default b 0

t=60000*a+1000*b

if t<1000 then let t=1000

print "Use Tv or M mode."
print "Use Continuous (burst) &"
print "High-Speed if available."
print "Use MF mode at infinity."
sleep 2000

set_tv 0
press "shoot_half"
sleep 1500
press "shoot_full"
sleep t
release "shoot_full"
release "shoot_half"

end

////////////////////////////////////////////////////////////////

I recommend the Canon IXUS 100IS: retails for around €180 here in Europe.

I had a bit of a bother getting CHDK onto my camera (I run Karmic Koala on my laptop).
This page helped: http://chdk.wikia.com/wiki/Bootable_SD_card
posted by vostok at 8:46 PM on February 5, 2010