A Little Experiment with Focal Length

by | Jun 22, 2020 | Perspective | 1 comment

I’ve been having way too much fun preparing the Premium Training for next week’s photo assignment launch!

After doing some video recording with Jonathan at a lake, we went driving around on some local back roads to find a good spot to run an experiment I wanted to do with focal length.

I wanted to illustrate how the relationship between the subject and the background changes based on your focal length. While keeping the subject the same size, the objects in the background get bigger and bigger the more you zoom in.

For example.

At 16mm. The Outback is our subject and the covered bridge serves as a nice secondary element in the background.

We observe that the Outback is quite distorted, and that the bridge is fairly small in comparison to the size of the Outback.

Stepping back and taking in the scene at 35mm, the Outback is still taking up the same basic amount of space, but it now looks a little more natural and the bridge has suddenly become much larger.

Jumping all the way to 100mm, I’m still trying to keep the Outback the same basic size, but now the bridge is so huge it’s impossible to fit the whole thing in the frame!

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The car didn’t move, the bridge didn’t move  (I’m pretty sure) . . . all I did was step back and zoom in more with each shot.

And this is a really great way to illustrate how the relationship between the subject and background changes based on focal length. You can use it to your advantage however you want, whether it’s to bring more attention to the subject, make objects in the background look smaller or larger, or help make the foreground feel more connected to the background.

Understanding the role of focal length in a photo is really quite important in photography, and absolutely integral to composition.

It’s kinda neat how this is a lot like life too. Depending on what lens we’re looking through, what might seem like a little problem to one person may seem like a big problem to someone else! Knowing that everyone may take a different perspective on the same thing helps us to respond to drama in relationships with a little more patience, understanding, or whatever quality is required for the situation. And it’s nice to know that, through God’s lens, everything is the exact size it should be. Smile

After spending about half an hour at this bridge and trying all sorts of angles, I decided I couldn’t use this set of examples for my video because there was no way to continue the comparison up to 200mm, the way the road curved and the bank rose up steeply beside it. I ended up trying 2 or 3 other spots before landing on a place where I could get an example that really illustrated the concept the way I wanted it to. I suppose it takes a flat stretch of road, and we don’t have too much of that around here. Smile

1 Comment

  1. Clara Johnson

    Thank you for this post, James. Focal length is an aspect of photography that I’ve kind of forgotten about the last few weeks, so I’m excited now to do some experimentation.

    I appreciate the applications you make. God is so good to give us so many hands-on illustrations of different aspects of life, worldview, vision, relationships, and spiritual growth. Thank you for pointing us to Christ!


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