Using ExifTool to find your most used focal length

I would like to get a better quality zoom lens, so I’ve started looking around the web for recommendations on replacements. The options seem endless. I’m even considering a couple of primes instead of one zoom.

Background: I only have two lens; the EF-S 17-85mm kit lens that came with my Canon 40D and a Canon EF 80mm 1.8.

Naturally, one of my first questions is… what focal length should I get? The 17-85 is a good range, but do I really use the different lengths? Could I just get a nicer, wide prime and physically move in or out to compose?

That got me thinking… I wonder what focal length I use most of the time?

The answer:
I use my 50mm 25% of the time
I use my 17-85mm 75% of the time

Specifically,
17mm: 17% of the time (Yes, I double checked the math.)
50mm: 25% of the time
85mm: 14% of the time
Most of the remainder is wider than 50mm (47%)

Picture 1.png

How do I know?
Phil Harvey has created a really cool command line tool called ExifTool that can scan all your photos and export a list! From there, you can open in Excel and evaluate your data. It works on Windows or Mac.

Conclusion
I think I will look for a better lens in the 17-55 range. And also something longer than 85mm.

Phil’s Website: http://www.sno.phy.queensu.ca/~phil/exiftool/

Documentation: http://www.sno.phy.queensu.ca/~phil/exiftool/exiftool_pod.html

How it works: I use Lightroom on a Mac to manage my photos, so I navigated to my Pictures directory in terminal:

cd /Users/(myusername)/Pictures

then ran this script

exiftool -r -T -filename -focallength -ext CR2 2008 > 2008.txt

That scans all files ending in “CR2” in the 2008 directory (AND all subfolders) and exports them to a file containing the image name and the focal length. The file is named 2008.txt. I opened the txt file in Excel and created a pivot table to find the sum of each focal length (or you could use another method).

Feel free to comment if you want to try it, but need help.

6 Comments

  1. Thank you very much!! Greatly empowering. Just what I needed as I’m looking forward to understand my ‘focal length habits’, shed the extra lenses and concentrate on a few good (possibly also new) ones that suit my style best. Super thumbs up!!

    Reply
  2. This will give you a text summary for the same data, which is probably easier to work with.

    awk '{print $2, $3}' 2008.txt | sort | uniq -c | awk '{print $2, $1}' | sort -n

    Writing the same summary to a csv:

    awk '{print $2, $3}' 2008.txt | sort | uniq -c | awk 'BEGIN { OFS = ", " } ; {print $2, $1}' | sort -n > 2008.csv

    It’s worth pointing out that as the focal lengths increase, they become more similar to each other – a 149mm and 150mm focal length are closer to each other than a 14mm and 15mm focal length.

    Reply
  3. Thank you another great write-up, I take pleasure in reading through everything you need to point out even if I would not constantly recognize. It is not exactly the same here is Most of Asia. Asians possibly visualize it a little in different ways. Which i love to look for a Cookware girl’s standpoint.

    Reply
  4. Other explanation is that I really like landscape photography at wide angles. I’m planning to get Canon 10-22 soon when I find the money for it.

    Reply
  5. Strange, my results are exactly as yours 🙂 I have also the same 17-85 lens. 99% of photos are shot either at 17 or 85 mm. I explain this to myself in that way: I keep the lens at its most-retracted state which is 17 mm. When I shoot I’m too lazy to adjust the zoom, so I shoot most at 17 mm. But when I want to zoom something, I zoom it to the end.

    Check it out here:
    https://spreadsheets.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AjZHxod5g1j2dDJJYUJlQVhic3hCc19DTWZvd0xJS2c&output=html

    Reply
  6. Awesome, just what I was looking for!

    Thanks!

    Reply

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