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Date: | Friday, May 21st, 2021 |
Lens: | 14–24mm f/2.8G ED AFS Zoom-Nikkor |
Photographer: | John Harvey |
Tag: | city, sunset, Stanley Park, freighter, time lapse |
Larger image: | 2000 x 1332 |
Raw image: | 3240 x 2160 |
John Harvey Photo > Blogs for 2024 to 2005 > May 2021 > Freighters Under Lionsgate At Sunset
Last Modified Saturday, January 28th, 2023 at 23:16:38. Edit
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This sequence is 1064 frames, taken every 8 seconds. I started at 7:51pm at f6.3, 1/3200 (-2 exposure compensation) and ended at 10:13pm at f4.5, 6 second exposures). It was shot in aperture priority mode.
I was standing on the lions gate bridge which introduces some challenges. First - the bridge has lights and you can see them start to dominate the park lighting in the last 1/3rd of the video. The much bigger problem is that the bridge moves a LOT. The frames have both a vertical translation and rotation element. I used ffmpeg to reduce the motion, but because this image is dominated by the clouds and boats I had to mask out (using a blur) much of the image so that the video stability detect code could find the motion. The code was:
# Gather the source images into a movie:
ffmpeg -framerate 30 -pattern_type glob -i 'DSC_*.jpg' -c:v libx264 LionsgateFreightersHg.mp4
# blur out most of the movie except the cliffs on the left and the mountains on the right
/usr/local/bin/ffmpeg -i LionsgateFreightersHg.mp4 -filter_complex "[0:v]boxblur=50[bg];[0:v]crop=w=1078:h=987:x=0:y=1038[fg];[bg][fg]overlay=0:1038[c];[0:v]crop=w=1125:h=516:x=2114:y=776[fg];[c][fg]overlay=2114:776" -map 0:v blurredVideo.mp4
# Use the blurred video to generate the transform estimates. Because of the minimum constrast requirements, the stability detect can't detect the clouds. ocean or boats.
/usr/local/bin/ffmpeg -i blurredVideo.mp4 -vf vidstabdetect=stepsize=16:shakiness=4:accuracy=15:mincontrast=0.4:show=1 cropVectors.mp4 -f null -
# Use the transform vectors to make the final video.
/usr/local/bin/ffmpeg -i LionsgateFreightersHg.mp4 -vf "vidstabtransform=input=transforms.trf" -crf 20 LionsgateFreightersStabilized.mp4
There are a few large ships in this timelapse. The first is the Bulk Carrier Kinoura followed by the Island Trader Tank Barge and finally the Bulk Carrier Sunny Hope. There are at least a dozen smaller ships including a police boat.