Nerd Notes: Focal Length and The Paradox of Choice

Ok, so before I get started, I have to warn you that this is a somewhat technical post (hence the name, “Nerd Notes”).  Since I’m a technical guy by training, I have a built-in (though not quite morbid) curiosity around data.  The stuff below is not for the faint of heart if you are averse to technical matters, but if you persevere you may find it useful.  What I’m going to try to explain is how you can analyze your shooting habits using real data.  Why in the world would this be useful?  Read on.

After a few years trying my hand at photography, I found myself feeling confused about what the right focal length was for me to make my images.  Should I be shooting at 18mm?  35mm?  50mm?  75mm?  300mm?  As a result of my confusion, I found myself buying lens after lens on eBay, only to try one for a few days and put it on a shelf, telling myself I’d use it again someday.  Eventually, I ended up with a shelf full of prime lenses, an 18-30mm wide angle, a high quality 24-70mm, and a 70-200mm long lens.  Over the next few years, I shot and shot and shot, and one day I realized that I rarely ever took the 24-70mm lens off of my DSLR.  But since that’s a pretty bulky lens and a hefty kit to carry around on the street, by that time I’d also purchased a point-and-shoot camera, a rangefinder camera with more lenses, and accessories for those as well.  I was new, and this was getting expensive; especially considering the fact that I wasn’t making any actual money off of my photography (yet).

As a quick aside, from my teen years until my early 30’s (before bad knees and photography came along), I was a pretty good basketball player.  Without exaggerating as a shooter, on some days I was exceptional.  But one thing that was perhaps both a benefit and a liability in my hoop game was that I was probably a little too analytical.  Even in random pickup games I was interested in my own shooting and defensive tendencies and those of whoever I was playing against.  Is he right or left handed?  Does he jump off his right or left foot?  Is he impulsive enough to fall for a pump fake?  Are his arms long enough to catch me on a reverse layup?  I didn’t have actual data at my disposal, but man, I wanted to know.  I’m old now, so I don’t care nearly as much anymore; I just go in the gym and shoot around until the young fellas show up.

But as I transitioned from basketball to photography and faced a creative dilemma over what focal lengths suited me best, I similarly sought to analyze my shooting tendencies.  Knowing that each digital image produced something called EXIF (aka “Exchangeable image file”) data, I figured there had to be an easy way to see all of the focal lengths that I’d shot at over those first few years.  Beyond that, I thought it would be helpful to understand what focal length I tended to shoot at most, both for my best, “keeper” shots and for everything else.

As a longtime Adobe Lightroom user, that was the first place I looked.  There are ways to search on, edit and even delete EXIF and metadata, but I couldn’t find a simple way to just create a single list that showed EXIF for all of my images.  After a bit of Google searching, I found a tool (on MacOSX, but also available on Microsoft Windows) that ran independently of Lightroom, creating a list file (called a “.csv”, or Comma Separated Value file) that I could then import into a spreadsheet (in this case, Microsoft Excel).  Let me show you how (WARNING: Here’s where things get a little nerd-knobby; feel free to jump to the conclusion if you feel nausea):

  1.  Find the tool: the tool I found is simply called “ExifTool”, by Phil Harvey.  You can download it for free here.Screen Shot 2017-08-03 at 10.57.52 AM.png
  2. Install the tool:  On MacOSX, the tool will install by default (a package file called ExifTool-10.60.dmg) into /usr/local/bin, but you won’t need to remember that unless you want to delete the file again later.Screen Shot 2017-08-03 at 10.58.52 AM.png
  3. Make a note of the image folder that you want to analyze:  I haven’t owned a zoom lens since 2015 (more on that later), so for the purposes of showing a good example, the folder I’m going to analyze is on an external hard drive called “REJECKT”, in a folder called “_Sony a99” and the “2015” subfolder.  Making a note of the path (see item #5) where your image folder is on your computer is relevant because when you run the tool, it will need directions to the folder in order to create the data you need.Screen Shot 2017-08-03 at 12.33.12 PM.png
  4. Get to a Command Prompt: If you ever want to do anything really serious on your computer (or dangerous, for that matter), you generally need to be able to find the command prompt (or Terminal, as it’s called on a Mac).  On a Mac, it’s usually located in the Applications -> Utilities folder.Screen Shot 2017-08-03 at 1.29.34 PM.png
  5. Type out the command:  This is the most technical part of the instruction.  Type out the exiftool command, along with the additional instructions for the tool to create a CSV file based on every image in that Sony a99->2015 folder.  In my screenshot, you’ll see the path (as mentioned in Item #3) looks something like “exiftool – common -csv -r /Volumes/REJECKT/_Sony\ a99 /2015 > BDMetaNerd.csv”.  In place of the the stuff I wrote in bold print, you’ll need to replace it with your specific path.  Once you have the full command typed out, press Enter.  You may need to wait several minutes for the function to complete if you have lots of images in the folder you chose.  But don’t panic.  You can do this.Screen Shot 2017-08-03 at 12.35.15 PM.png
  6. Give the command a name for the list file you are asking it to create: The command needs to create a report of it’s work.  This report needs to go into a file.  Your mission, should you choose to accept it, is to give that file a name.  In my example, I named my file “BDMetaNerd.csv”.
  7. Locate the report file you just asked the tool to create: If you are using a Mac, that “BDMetaNerd.csv” file will be created in your main user directory.Screen Shot 2017-08-03 at 12.35.44 PM.png
  8. Open the “BDMetaNerd.csv” file (or whatever name you called yours): Now we’re getting to the good meat.  Using a spreadsheet app, open the file that your command just generated.  I used Microsoft Excel.  You’ll see a ton of data about your images that you may not even know existed, from the “FileName”, “FileSize”, “Model” of camera, “DateTime” you shot the image, “ImageSize”, “Quality” of the image (raw file, jpeg, etc.), “FocalLength”, “ShutterSpeed”, “Aperture”, “ISO”, “WhiteBalance”, and “Flash”.  We’re interested in the column that says “FocalLength”. Screen Shot 2017-08-03 at 12.36.04 PM.png
  9. Clean up the column data: Ok, so we are thisclose to the part where you see what your average focal length is.  But in order for the spreadsheet to do that mathematical calculation for you, it needs to be working with numbers that it understands.  You will notice that in the “FocalLength” column, each entry has the letters “mm” next to the numbers (representing millimeters, of course).  You may understand that, but Microsoft Excel doesn’t.  So we need to take out all the little “mm’s” before we do the math.  To do this, first click your mouse on the column that contains the focal length numbers (in this screenshot, that means I clicked on the letter “H” to highlight the entire column).  Next, locate the “Replace” function in the spreadsheet app (in this case, the “Replace” function is found by clicking on “Edit”, then “Find”, then “Replace”).  Click it.  Click it good.Screen Shot 2017-08-03 at 12.37.26 PM.png
  10. Eat all the M&M’s: In the “Replace” screen, under the “Find what” box, type in the letters, “mm”.  Don’t type anything else on this screen; just click “Replace All”.  Immediately, the “FocalLength” column will only have numbers in it.  Now we’re cooking.Screen Shot 2017-08-03 at 12.37.39 PM.png
  11. Calculate the Average “FocalLength”:  As Drake would say, “just hold on, we’re going home.”  Anyway, now we’re ready to do the math.  Or, rather, to let the spreadsheet app, Excel, do the math.  To do this, scroll to the last entry in the “FocalLength” column, and click the empty cell right after the last number that you see.  In my example, I clicked the empty cell in column H right after the number 35.  Then, look for the Greek symbol Screen Shot 2017-08-03 at 1.56.02 PM.png, and click the little down arrow to see an option called “Average”.  Click it.  Click it good.Screen Shot 2017-08-03 at 12.41.13 PM.png
  12. Turn the gibberish calculation into a real number: In that empty cell that you selected before you ran the “Average” command, you will see what looks like a formula.  Actually, it is a formula that is reading all of the lines of the spreadsheet in the “FocalLength” column.  It’s ready to give you your number – all you have to do at this point is click Enter.Screen Shot 2017-08-03 at 12.41.28 PM.png
  13. Drums, please: Here it is, the groove, slightly transformed… Just a bit of a break from the norm…  Just a little somethin’ to break the monotony, of all that hardcore dance that has gotten to be –

Sorry, Charlie Murphy.  I was having too much fun.  Anyway, after you hit Enter, you’ll see the calculated average focal length for every image file that you selected for analysis.  In my example, I’ve just analyzed over 500 images shot in 2015 and learned that, on average, the focal length I used was “37.6447106”, which in practical terms is rougly 35mm.  Screen Shot 2017-08-03 at 12.41.45 PM.png

Too Long, Didn’t Read

What did I learn from this exercise, and how did it help me? Long story short (TOO LATE!), I learned that I was wasting my money buying lens after lens when what I most often gravitated to usually fell in the 35mm range.  Making an assumption of plus or minus a few mm, for me that meant that I could probably be pretty happy with just a couple of lenses.  So, in 2015 I sold off all of the extra DSLR lenses, with the exception of a 50mm, a 35mm, and a 24mm.  For what I like to shoot, these three prime lenses pretty much cover all of my needs.  As a result, when I head out to shoot these days my decision on what to pack is pretty simple, and I’ve re-invested the money I spent on those useless lenses elsewhere (DRONES!!!).  I also now have a pretty powerful deterrent from buying whatever the newest, hottest lens on the market may be: hard proof that over time, no matter what choices I have available to me, I was most comfortable and effective within a specific range.  Anything beyond that range was essentially a point of diminishing returns.

This reminds me of Barry Schwartz’ Paradox of Choice; that, giving ourselves too many choices may be both expensive and counterintuitive to the creative process.  If you’ve read this far, congratulations.  It means you are at least thinking about whether you have your own paradox of choice, whether your challenge is creative blockage or an urge to purchase more kit that you may not use.  You don’t have to build a Rube Goldberg machine to get to a decision, as perhaps I’ve done here.  But, giving some thought – whether qualitative or quantitative – to your choices may very well empower your creativity in the long run.