Sunrise over Pittsburgh
I got up extra early early this morning (but not quite early enough) to watch the sunrise from Mt. Washington. Here is a time lapse video I made of the event:

Technical details after the break.

First off, I set up the built-in interval timer in my Nikon D700 DSLR to capture a frame every 2 seconds. The camera itself was set in aperture-priority mode, f/9, with manual focus at infinity, and matrix metering forced 1/3 stop down. I think if I attempt this again, I will put the camera in full manual mode so the brightness doesn’t creep around. This was all well and good, but the camera rolled over the 10,000 frame mark, so the last 200 files I had started with DSC_0xxx.JPG. To make sure that mencoder would pick them all up in the right order, I renamed these files using rename:

rename 's/DSC_0/DSC_A/' *.JPG

The files were taken at a resolution of 2128×1416, which is the smallest setting available on the camera. I wanted the video to be in 1080p format, so I used mogrify to scale the files down and then crop the top and bottom off:

mogrify -resize 1920x1278 *.JPG
mogrify -crop 1920x1080+0+87 *.JPG

Finally, I messed with mencoder for a while before finding an encoding setting that looked reasonable. I don’t know a whole lot about video encoding, but this two-pass Xvid encoding looked reasonable:

mencoder -ovc xvid -xvidencopts pass=1 -o /dev/null -mf w=1920:h=1080:fps=30:type=jpg 'mf://*.JPG'
mencoder -ovc xvid -xvidencopts pass=2:bitrate=8000 -o sunrise.avi -mf w=1920:h=1080:fps=30:type=jpg 'mf://*.JPG'
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3 Responses to Sunrise

  1. Lee Johnson says:

    Very cool. Although, like you said, a fixed aperture and shutter would better convey the brightness gain of the rising sun. Now I want to try this myself. Hmm, a squash plant growing perhaps … Robin claims they get a new leaf every day. :)

    And, how did I miss the rename command? All this time I’ve been using a one-liner bash for loop with ugly variable substitution. Although, from the man page, it is not at all obvious that rename accepts a regexp.

    • mahto says:

      Yeah! I’ve always wanted to do a plant one; in my head i would grow something that sprouts up really quick, and make it ‘dance’ by growing it under an artificial grow light that I move around, with the intent of getting it to grow through some complex shape.

      Not sure about the rename command; it slipped by me for some time too.

  2. Matt says:

    That’s cool. I’m surprised that with the exception of the cars, everything looks pretty continuous – I’d expect the smoke to be choppier given a 2s interval.

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