26 Weeks Photo Challenge #6: Depth of Field / by Simeon Smith

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Now we’ve discussed the only thing that you can affect outside the camera (light!!) we’ll move through the things you can affect inside the camera. 

I’m trying to keep the series beginner-friendly, but there’s a lot of jargon this week. I’ve tried to explain things as I go, but google stuff if you get lost, or tweet at me if you can’t find the answer. If this is all old news to you, try out the challenges anyway - it’s important as more-experienced photographers to keep breaking our technique down to remind ourselves of why we do things the way we do. 

“Everything that needs to be said has already been said. But since no one was listening, everything must be said again.” ― André Gide

If you’re using a camera with conventional design (i.e. 99% of cameras on the market), you’ll be able to control aperture (how much light you let in) , shutter speed (for how you let light in), ISO (sensitivity to light). These, along with focus and focal length (kind of like zoom… well not really… google it), are the tools you have at your fingertips to control your images. 

Some cameras may not have direct control over all of these parameters, but over the next few weeks we’ll learn how to control these on a camera that allows manual control, or how to force a camera that doesn’t have manual control. 

Let’s start with aperture: 

Your “aperture" is the size hole behind the lens that light travels through. We measure this in "f stops”, and depending on your camera and lens you’ll be able to select between a low number, for example f1.2 to a high number, like f22. The lower the number, the wider the hole, the more light you’re getting.

(geeky bit: the “f stop” number relates to a division of a focal length. So on a lens with a focal length of 50mm, f1 would be an aperture, or hole, exactly 50mm wide. f2 would be 25mm wide, and so on right down to the narrowest apertures like f22, which would be 2.27mm wide)

So why is this important? Well, two things. 

Firstly, the wider the aperture the brighter your photos will be. If your camera is working out exposure (how bright a photo is) for you, then whoopdidoo… who cares? 

The second reason we use different apertures is “depth of field”. Depth of field is how much of a photo is in focus. We’ve all seen portraits with beautifully sharp faces, and beautifully blurry backgrounds. We’ve all seen photos where EVERYTHING is in focus, almost to an unnatural degree, after all the eye works like a camera we don’t usually see everything in focus. 

So your task this week is to be intentional with your depth of field. 

If you have a camera that allows it, set the camera to Aperture Priority (Av mode on most cameras). This will allow you to change the aperture, and the camera to work out everything else for you for a beautiful exposure. Shoot things with a wide aperture, with only a select few objects in focus. Shoot the same scene with a narrow aperture and notice how the background changes. 

On simpler cameras, or camera phones there are a couple of ways of “forcing” aperture. Usually “portrait” settings will use wide apertures, and “landscape” settings will use narrow apertures. 

You can also “force” a shallow depth of field by shooting in low light, shooting with a large distance between the foreground and background and shooting with things REALLY close to the lens. 

Questions: 

  1. Look back at your masters. How do they use depth of field in their work?
  2. What are the advantages of a shallow depth of field? What are the advantages of a deeper depth of field?
  3. How should depth of field affect your composition?

Fuck me, that was long.  I’ve bored myself this week. But playing with aperture is one of the most satisfying things you can do in photography. Give it a go!