Download pdf - Mako lightning talk

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Page 1: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Lightning

Atmospheric discharge of electricity.

Often accompanied by thunder.

Travels at 60,000 m/s

30,000 °C (54,000 °F)

Page 2: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Photographing Lightning

A tricky problem:

Hard to predict.

Over pretty quickly.

Cameras can get wet.

Page 3: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 4: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Approaches using CHDK

Free Software (CHDK) offers two approaches:

The old way: “Wait and hope.”

The new way: Motion detection.

Page 5: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Wait and Hope

Using a CHDK intervalometer script to take long-exposure shots repeatedly.

1-15 second exposures (1-second can work better for lightning) can keep shutter open between 80-95% of the time.

“Dark frame subtraction” addresses noise from long exposures.

Tends to work poorly during the day.

http://chdk.wikia.com/wiki/UBASIC/Scripts:_OMNI_Intervalometer

Page 6: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Motion Detection

A user named “MX3” wrote motion detection functionality for CHDK using variance in luminance.

Triggered by the “lead” strike which immediately precedes every main lightning strike.

Every photograph on camera has a lightning strike.

Works in daylight or even without tripod.

Page 7: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 8: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 9: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 10: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 11: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 12: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 13: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010

Page 14: Mako lightning talk

ben

jamin

mako

hill :: lig

htn

ing

:: deb

con

f 2010