What’s the correlation between the exposure time of your photographs and the time of the day?

My digital photo archive spans 15 years and holds about 12,600 pictures (not so many, after all). I’m curious to see if there is a correlation between the exposure time of my photographs and the time of the day they were taken. A rather simplistic observation, perhaps.

In short: there’s nothing spectacular about this correlation, but it’s nice. The morning hours are the ones with the lowest average exposure time at around 1/320 s between 9 and 10 AM . There’s a sharp increase between 12 and 1 PM, then it increases again after 4 PM towards dusk. I don’t take many pictures at night!

See for yourself.

expotime2

The most frequent values for exposure time are in the table below. 1/30 s is the typical exposure time when using the flash, and it’s recognisable in the plot above.

1/n soccurrences
8001986
10001178
30943
400547
250488
640458
200450
500388
320342
160337

The Python and R scripts are at Codeberg https://codeberg.org/steko/expotime but were originally at Gitlab.com (giving GitLab a spin since GitHub is a monopoly and I don’t like that). I’m still doing some experiments with the source data, then I’ll upload those as well.

Di Stefano Costa

Archaeologist, I work in Liguria where I live with my family. In my studies, I spent most of my energies with the Late Antique and Early Medieval/Byzantine period on the northern side of the Mediterranean, focusing on pottery usage patterns. I'm also involved in open source and open knowledge initiatives.

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