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What is Depth of Field?

 26th May 2020

Depth of field. What is it? How do I use it? What impact does it have on my photography... what is it again?

Having control of your camera gives you the confidence to become a better photographer. Knowing how the core features work so that you are leading the shot is the difference between a fluke and a well thought out photograph.

There are so many new features that can make the fundamentals a little hazy, which is why I am using this platform to clear all the distractions and get you focusing on what matters the most on your photography journey. 

Today, we’re looking at depth of field. This blog will define it, explain it, help you use it and give you some top tips. 

What is depth of field?

Depth of field is one of the most critical features on your camera. It’s really important that you understand the theory and put in plenty of practice too.

Depth of field is the distance between the closest and farthest object that is in focus. It decides how sharp your image will be. Imagine a block of sharpness that you can move front to back in your picture. This shifts as you change your aperture. 

If you’re shooting landscape you want a big block from your camera off into the horizon so that you retain all that detail with a larger depth of field. 

Zurich 003

I took this one in Zurich and you can see how sharp the image is in the distance as well as along the waterline.

If you’re taking a portrait then you will want to focus on the person and soften the background so you will use the smallest depth of field.

Zurich 023

Take this photo for example, the lovely subject is totally focused and just behind her it softens so that she remains the focal point of the photograph.

Here are some helpful guidelines to keep you on track;

The lower the ‘f’ number you set the shallower the depth of field. Use low 'f' numbers for shallow depth of field when you want to have a sharp point in the picture but have a blurred background / foreground.

f3.5 = shallow depth of field
f11 = middle depth of field
f22 = masses of depth of field

Now that we know what depth of field is, let’s look at how to use it!

How to use depth of field

We already know that depth of field determines focus but what is the best way to put this into practice? Practicing your depth of field is the only way to grasp how it works in the real world. I wholeheartedly encourage you to set up a test ground and see what the various depths of field do to the same image. An easy way to do this is to choose a subject along a straight line, put tape on a wall for example and shoot along the wall putting the background and foreground in various stages of focus as you change your aperture. 

Here are some key pointers to help you set up;

  • Set your camera on aperture priority
  • Put your shortest lense on or set zoom to lowest focal length
  • Use manual focus for the control
  • Use a tripod to avoid camera shake

Once you’re set up you can choose a subject along the wall or line you’ve chosen and experiment with different depths of field. 

I’ve recorded this exercise because it is so useful in explaining the technical and creative aspects of depth of field. You can watch it here.

Over the years I’ve developed ‘golden rules’ of depth of field to make it easier to put into practice;

  • Low ‘f’ numbers have shallow depth of field
  • High ‘f’ numbers have greater depth of field
  • With a short lens you can get lots of depth of field
  • With a long lens you get only a little depth of field

Depth of field is one of the five cornerstone features of your camera so make sure you invest time into really understanding how to use it because it will make a difference to your photography.

Top tips

Here are some of my top tips for you to think about when you’re out there practicing;

  • Small aperture can set off camera shake so think tripod!
  • Aperture size is the main control but focal length does make a difference
  • Think about your shot and plan your settings
  • Be creative, don’t feel the need to have a soft background for a portrait or a focused one for landscape
  • Practice practice practice
  • There are different techniques out there for depth of field, don’t jump in before you have the confidence of control

My Masterclass in Photography was designed to help you gain confidence with how your camera works and put you in the driving seat. In the first week we look at your camera and in week two we dive into aperture and how to use it both technically and creatively. 

If you need some more guidance to get your photography to the next level I highly recommend this course, and so do loads of previous students. Learn more about the course here.

It’s okay to make mistakes when you’re learning so don’t be afraid of not getting it right first time or every time, the beauty of learning is how much your photography will evolve so jump in and enjoy it!