Focal Length and the Photo Taking Process

If you were to over-simplify the photo taking process, it is minimally three steps:

1. Find a subject.
2. Set Up the shot
3. *Click*

But that is a bit of a gross understatement and it does no justice to our craft to speak of the process so lightly.  Each one of those steps could, after all, be divided further.  Much further.  But that’s where everyone’s process will differ a little bit.  For that reason, we don’t like to get too specific here at Shutter Photo.  We strive to teach good habits, but we aren’t trying to tell you that our way is the only way.  So we like to focus on different components of the process so that you can garner what you wish and maybe mix-and-match each step as you see fit.  The end result is ultimately of your choosing.

This week, we’re going to talk about the most often neglected setting from Step #2:  Focal Lengths.  In an article about the prime vs. zoom debate a couple weeks ago, I touched on how the focal length selection is often selected in the wrong order.  It’s not uncommon for us to find a subject, plant your feet and then zoom to a focal length that frames up the shot the way you want it.  This is, of course, why prime fans claim that zooms make you lazy.  But I think it’s really just a bad habit that can be corrected.

Focal length affects one key element of your composition:  Angle of View.  Angle of View is not something we commonly think about, but it has more impact on the appearance of your shot than you could imagine.  When the finished product is going to be a fixed dimension – say an 8” x 10” photograph – changing the angle of view within the shot is going to distort and change your perspective.  Objects in front of or behind the subject are going to stretch or compress depending on your angle of view.  A narrower angle of view will result in the space getting compressed from front-to-back.  Alternatively, a wide angle of view could distort the shot so that a corridor looks incredibly deep.  I won’t get into all the details here, but if you want to know all the specifics, I would encourage you read our article, Zoom Factors:  Why Your Feet Cannot Be Replaced By A Zoom Lens.  All I want you to realize at this very moment is that the angle of view can change one’s perspective within a photo.  And the only way to control angle of view is to change your focal length.

A Brief Exercise

At 24mm, there appears to be a good distance between the turtles.

Let’s do an exercise to teach you about your lens:  Grab your favorite zoom lens and an object roughly about the size of your fist:  An action figure, a toy car – something with some angles.  Place it at the center of a table – preferably a table that has a lot of room around it at least on one end.  This will be your subject.  Envision that you will be taking the photograph from one end of the table very close to the table’s surface:  Remember that axis.  Now I want you to grab two other objects each about the same size.  Place one at the end closest to the camera and slightly left of your subject (so you can clearly see most of your subject) and place the other at the far end of the table slightly to the right of your subject.

At 35mm, the turtles appear to be closer.

Now it’s time to start looking through that camera and taking some photos.  I want you to position yourself (you have to move, let’s not be lazy) so that you have a good handle on the relative size of your subject through the viewfinder.  Use your focusing points or your viewfinder grid to eyeball the size.  Remember that.  Every time you change your focal length, you are going to have to move your body and your camera closer or farther from the subject so that the subject always remains the same relative size.  I want you to take several photos at varying focal lengths.  Take one at the shortest focal length, one at the longest and then at least a handful of spots in between.  Use focal lengths that are marked on your zoom ring (maybe do a shot at each one).  Don’t worry about aperture or shutter speed.  Those settings won’t affect what we’re looking for.

Finally, at 100mm, the turtles appear to be close enough to touch. But it’s an optical illusion thanks to a very narrow angle of view (

Now let’s compare the shots.  What do you notice about  your subject?  What do you notice about the two other objects that you placed in front of and behind your subject?  What about their relative positions to each other?  You’ll notice that at your longer focal lengths, the scene will appear very shallow.  The objects may appear nearly on top of each other, and that one in the back will look much larger than you think it should.  The inverse is true of the shorter focal lengths.  With short focal lengths, the scene will appear stretched.  This is all because of the differing angle of view, and this is why focal length – which controls angle of view – is so very important in your photography.

The 100mm focal length is particularly distorting.  Our subject still looks about the same – at least his distortions aren’t noticable.  But he looks close enough to touch the other subjects.  If it weren’t for the shallow depth of field, you might believe me entirely.  This is how celebrity rumors get started.  Tabloid photographers are great at making celebs look much closer than they really are.  But I digress.

Focal Length Selection:  Best Practices

If I haven’t yet beat the concept into you, I’ll reiterate:  Focal Length is an independent “setting” that must be fully considered before snapping the photograph.  If you’re using zoom to “get close” to an object, you’re not thinking enough about your photographs.  That’s a bad habit and you need to break it.  Now.

So let’s look at that process with a little extrapolation around the focal length part:

1. Find a subject
2. Set Up The Shot:
   1. Select an appropriate focal length – one that is flattering.  Or I suppose you can select one that is unflattering.  The artistic intent is your own.  But at least you’re thinking about it.
   2. Position yourself appropriately – Verify your perspective, be aware of object merges and make sure you’re happy with the composition.  If not, select a new focal length and reposition.  You’re going to have to move.
   3. Select your other settings: ISO, aperture, shutter (but that’ll have to be a different article)
3. *Click*

Prime shooters: You are to be held to the same standard.   If the 50mm is on your camera and its angle of view is not what you want for the shot, you’re just going to have to change the lens.  Changing position and “zooming with your feet” to fit the shot, simply because that’s what you have mounted, is equally as lazy.  You can’t change the angle of view on your prime lenses.  This is fact.  And this is why you have twice as many lenses as the zoom shooters.  So use them.

Favorite Focal Lengths:  This Is The Part Where You Have to Practice…

Selecting the appropriate focal length is not something I can give you a formula for.  The overall artistic intent is, after all, only yours to decide.  So I encourage you to spend several session of your own time thinking specifically about focal length.  You’re going to take hundreds of shots before you can truly get a feel for how each focal length looks in the finished product.  And you’ll need to do this with each of your lenses because each lens is different.  You will find your favorite focal lengths for specific subjects.  Commit these to memory or write them down so you don’t forget.

The goal is ultimately to have a few focal lengths roughly in your mind for every scenario.  The last thing you want to do during a session – especially a paid session – is to be found hunting for the right focal length for each shot.  You want to click as much as you can, so you can’t be wasting time trying to decide.  That is why I like to stick with the focal lengths that are explicitly marked on the barrel of my camera.  Knowing those, at least, allows me to go back and select the focal length without having to even look through the lens.  That is your toolbox.  Know it and know it well.  That will place you at least one step closer to perfection.