This last weekend, I had the opportunity to volunteer as a photographer for the Jonathan Jacques torch run. It was a great time. I took close to 500 pictures. I did notice that it felt like I was using the maximum focal length on my lens quite a bit. The only lens that I currently own is an 18-135mm lens that came with my D80 kit.
I took a look at Nikon’s site to see what lenses they have available. I really like the idea of an all-in-one& kind of lens and I found that Nikon makes and 18-200mm lens. This got me thinking, because Tamron makes a 28-300mm lens. If I go the Nikon route, I want to make sure I get enough lens.
Now, this really got me thinking. Being that I just shot 500 pictures, I thought it would be great if I could find out the what focal lengths I used and how they were distributed. I knew that there was some metadata stored in jpeg images, but I didn’t know how to get access to it. I turned to google, and I ended up finding a perl module called Image::ExifTool. This allows me to get access to the Exif metadata in the photos. Since I resized a bunch of the photos down to fit on my website, I grabbed a copy of these thumbnails and threw them in a directory that I could work in on my Linux machine. I installed Image::ExifTool, then sat down and started writing a script.
This output something like this…
thumb_DSC_0002.jpg FocalLength => 28.0 thumb_DSC_0003.jpg FocalLength => 135.0 thumb_DSC_0004.jpg FocalLength => 52.0 thumb_DSC_0005.jpg FocalLength => 18.0 thumb_DSC_0006.jpg FocalLength => 85.0 thumb_DSC_0007.jpg FocalLength => 85.0 thumb_DSC_0008.jpg FocalLength => 35.0 thumb_DSC_0009.jpg FocalLength => 32.0 thumb_DSC_0010.jpg FocalLength => 32.0
I then took this data, brought it into Excel, and calculated some statistics:
mean = 67.98193mm median = 62mm standard deviation =39.0633mm
So, the internal debate with myself rages on….I’ll probably end up with the 18-200mm lens. It helps that my father-in-law has this lens and I can go play with it on his camera side-by-side to my camera.