One of the things that I’ve wished for in Lightroom is a focal-length histogram. I’d love to be able to select a bunch of pictures and ask “which focal lengths did I use most often?” I mean, I know which lenses I use most often, but which focal lengths do I actually use?
Fortunately, it’s not too hard to do this outside of Lightroom. Just turn on XMP auto-exporting and then use the usual set of Unix tools to summarize a few thousand XML files. I used something like this:
$ find . -name '*.xmp' | xargs grep -h 'exif:FocalLength' | cut -d '>' -f2 | cut -d '/' -f1 | sort -n | uniq -c
That finds all of the
.xmp files in the current directory (and subdirectories), extracts their
exif:FocalLength lines, then extracts the actual focal length number, sorts them numerically, and then counts how many occurrences of each focal length it sees.
I ran this over all of the pictures that I took while on vacation, and found a couple interesting patterns. First, I usually shoot with lenses at either their short or long end; the middle of the range gets a lot less use. My most common focal lengths were
|Focal Length (lens)||Number of shots|
|70mm (24-70 or 70-200)||846|
A graph is (as usual) a bit more informative:
I shoot a lot of pictures in the 24-100mm range. 70mm is the most common, but the 35, 45, 55, and 65mm lines are all pretty big. It looks like I use my 24-70mm lens in the middle of its range quite a bit, while my longer lenses mostly get used at their extremes.