After reading a recent post by Jason, where he analyses the focal lengths he uses, I was inspired to do something similar.
I performed a similar analysis on all the photos I took in 2010, looking at which lenses I used most, and the focal lengths used. This was done in light of the fact that I have been thinking about maybe selling one of my lenses and getting one covering a slightly different focal length.



ExposurePlot is a useful application for performing analysis on your photos. Just point it at a directory of your photos, and it reads the EXIF data in all the photos in that directory and subdirectories, and generates graphs of the data.

The command-line exiftool provides similar functionality, but requires a little more effort to process the results.
For example, to extract the focal lengths of all photos and dump the results into a text file (recursively going through all subdirectories looking for photos), the following syntax can be used:

exiftool -r -focallength * > focallengths.txt 

If you are a Lightroom user, Lightroom can report various statistics by lens, aperture, focal length, and more. Just click the filter combo at the top right, and select "Metadata" to view the filter criteria.



During 2010, I took photos on numerous work-related interstate trips, visiting Sydney (twice), Adelaide (three times), Brisbane, Gold Coast, Roxby Downs, as well as a road trip through various locations in NSW, including Newcastle, Wollongong, Nowra and Botany Bay.
I also shot one wedding, did one family shoot, and took plenty of photos on several holidays with my own family.

moth and everlasting flower

Lesmurdie Falls National Park, Lesmurdie, Western Australia
Canon EOS 50D, 24-70mm f/2.8L @70mm, 1/1000 sec, f/4.5, ISO400

Note that these statistics shown below do not include the photos I have deleted, such as photos obviously out-of-focus - but only includes the photos I considered worthwhile keeping.



The table below shows the percentage of photos that were taken with each of my lenses during 2010.

lens	% of photos
Canon EF 24-70mm f/2.8L	59.4%
Canon EF 70-200mm f/4L	10.8%
Canon EF 35mm f/2	10.0%
Canon EF-S 10-22mm	7.5%
Canon EF 100mm f/2.8 macro	5.4%
Canon EF-S 17-85mm IS	4.4%
Canon EF 50mm f/1.8	2.5%

Looking at the focal lengths can also be interesting. The graph below provides an indication of the focal lengths of all photos taken during 2010. The coloured rectangles overlaid on the graph represent the focal range of each lens.

number of photos by focal length

Some comments on these results:

• the 17-85mm IS lens isn't shown on the graph above, as I only took a handful of photos with it (my son normally uses it)
• of the photos taken with a focal length of 70mm, 75% were taken with the 24-70mm lens, and the other 25% were with the 70-200mm lens
• I tend to use the wide and long extremes of my zoom lenses a lot
• I have been loving the 35mm f/2 lens, and have used it quite a bit (and as a result, the 50mm f/1.8 gets almost zero use)

With more than 50% of my photos being taken with the 24-70mm f/2.8L lens, you would think it must be my favourite lens. However, that's not quite the case.

As Belgian photographer Bert Stephani said last year on his blog:
Admittedly, Bert uses the 24-70mm lens on a full-frame body, while I use it on a 1.6x crop body, so it's a little wider for him than it is for me. However, I agree with his comments - and find myself using the 24-70mm f/2.8L lens because it is reliable, and it provides the focal range that I need for a lot of the photography that I do.
For example, when I shoot a wedding, most of the photos are taken with the 24-70mm lens, with the 70-200mm coming a distant second. The 10-22mm lens and some primes get occasional use during a wedding (although I should try to use prime lenses more during a wedding shoot).



I am not completely happy with my 24-70mm f/2.8L lens, because it is a big and heavy lens, it isn't as sharp as I expected it to be, and I find 24mm on a 1.6 crop body to be a little too long as a general-purpose zoom lens.
Because of this, I was thinking about maybe selling it and replacing it with either the Canon EF 17-40mm f/4L or the Canon EF-S 17-55mm f/2.8 IS lens. However, given the large number of photos I've been taking with the 24-70mm lens at 70mm, I think both the 17-40mm and 17-55mm lenses will be a little too short for my shooting style.

The Canon EF 24-105mm f/4L IS lens may be a better option, as it provides a longer focal range. While it does have image stability, it does mean losing a stop (from f/2.8 to f/4), and about 16% of the photos I took in 2010 with the 24-70mm lens were taken at an aperture larger than f/4 (f/2.8, f/3.2 and f/3.5).
Maybe I should keep the 24-70mm lens, and use my prime lenses more frequently.



Doing some analysis on the photos you have taken can be an interesting and worthwhile experience. It will give you a better idea how many photos you have taken with each lens, as well as the focal lengths you use.
This information can be particularly useful when you are considering upgrading one of your lenses, or buying an additional lens.

In this post, I looked at the photos I took during 2010, but it can also be useful to perform a similar analysis of the photos taken during a single shoot or on a single occasion.