Have you ever asked yourself, what's the best focal length for your first or your next prime lens? In case you are just starting with photography with zoom lenses only and never set a focal length consciously Adobe Lightroom may be able to tell you.
In Lightroom select the top folders containing all your pictures. Then open the Grid view in the Library module and select Metadata in the Library Filter bar on top of the grid. This will show you a couple of columns with selected metadata that you can filter for. Next you might have to change the displayed metadata by clicking on a column's header. In the end you should have one column displaying the lens model and a second column displaying the focal length like in the screenshot below.
From the list of lenses select a lens with a broad zoom range that covers typical focal lengths - typically your most used everyday lens. In the example here I have chosen the Canon EF-S 15-85 mm IS USM, which is a great general purpose lens for APS-C crop cameras. In the column displaying the focal lengths you see how many pictures were taken at which focal length for the selected lens now. Here you go. In my example we see a few focal lengths that are assigned to a significant higher amount of pictures than other focal lengths.
Naturally the lower and the upper end of the focal length range can be ignored. You hit the lower end each time you want to have more on your picture and would have needed an even wider lens, however it was not available at your hand at that time or you just might have been too lazy to change the lens. Same for the upper focal length, where you would have zoomed in more, if more focal length would have been available. Ideally you would do this test with a lens that offers a focal range like 8 mm - 500 mm - if this would exist (and even then you might experience the same effect).
To visualize the distribution of used focal lengths with the selected EF-S 15-85 mm I've created a chart, which omits the lower and upper ends of the focal length range:
As you can see there are three obvious spikes at 24 mm, 35 mm and at 50 mm. Coincidentally (or not?) these are standard focal ranges for prime lenses. However we are still talking about APS-C, so let's convert these focal lengths to their full frame equivalents:
So at full frame we see spikes at the most popular focal ranges:
- 35 mm, which is the standard focal length for street photographers,
- 50 mm, which is considered as the perfect normal focal length and the focal length of the most popular prime lens - the nifty fifty,
- and finally 75 mm, which is close to 85 mm as a flattering focal length for portraits.
Still coincidence? Maybe not.
As a last step, click on the focal length you want to examine more and Lightroom will show you for which kind of pictures you've used this focal length.
Depending on your shooting style the distribution of used focal lengths might look different for your case. I'd like to hear from you in the comments about your results. Are the spikes at the popular focal lengths really just a coincidence in my case?
Anyway I hope this tip helps you to find the most useful focal length for your next prime lens.