Single lens reflex cameras have interchangeable lenses that allow photographers to change the aperture of those lenses. The aperture is the hole inside the lens whose size is determined by you, the photographer. And that is as long as you’re using your camera in Manual or Aperture Priority Mode.
You may wonder why the size of the aperture matters to you as a photographer, but be assured that it does. The size of your lens aperture will determine the depth of field in your photographs.
And… it is the depth of field that will determine:
- where your viewer’s eye is drawn to in your photograph, and
- whether or not your photograph is telling a story.
These are the two ways you can use your aperture setting to control the depth of field in your photos, creatively. Let me explain in a bit more detail, but first things first.
Aperture is determined by the f-number on your camera and there is an inverse relationship between the f-number and the size of your aperture, so a small f-number (let’s say f/1.4) means that you are using a large, wide open aperture. A large f-number (let’s say f/22) means that your aperture is small and has narrow diameter. So I will use the term “large aperture” to mean wide open indicative of a small f-number and “small aperture” to mean narrow not-so-wide open indicative of a large f-number.
Here’s a statement to remember: the larger the aperture, the shallower the depth of field.
So what is “depth of field”? The best way for me to explain is to try and get you to picture in your mind a row of parked cars in a parking lot. Walk to the end of the row of cars, kneel down and then look straight down the row. Imagine taking a photograph of this row capturing the rear end of the first to the very last car. Now… the depth of field is the distance, that everything is in focus both in front of and behind the focal point. Every photograph has some level of “depth” thanks to the third dimension in our world. Notice I said depth and not depth of field.
The amount of “depth” in your photograph depends on your camera angle. If you take a picture of a sunset whilst standing, there won’t be much depth in the image. If you take the same photograph lying down, the photograph will have much more depth will the presence of the pebbles and stones in the immediate foreground and the sun being distant over the horizon. Remember this distinction between depth and depth of field.
So how can you use depth of field to draw the viewers attention to a specific point in your photograph?
By using a large aperture. This is very effective in portrait photography because large apertures are great when you want to blur out the background and bring only the subject’s eyes and face into sharp focus. And they do so because of their shallow depth of field. But is this a creative effect? Try it for yourself and see the effect a 50mm f/1.4 lens has on your portraits when shoot at f/1.4 or f/2 with bright lights or a colourful background.
There are many ways large apertures can be used creatively. In fact, Canon even make f/1.4 prime lenses in their wide angle range because they know that professional photographers love large apertures. In wedding photography, professionals use 24mm and 35mm f/1.4 lenses with flash to blur out the beautiful background lighting and fill the dancing newly-wed couple in the foreground. Large apertures work very well in candle-lit scenes. They are much loved by professional photographers.
How can depth of field tell a story in a picture?
This concept applies to landscape scenes where everything from front-to-back ought to be in sharp focus – there is no blurring going on. When everything is in sharp focus in the entire image regardless of depth, the scene tells you a story about itself.
A wide angle lens used in the beautiful African Masai Mara tells me a story about the watchful attentive zebra standing a few metres in front of my Land Cruiser, the care-free grazing wildebeests further away, the distant Acacia (also in sharp focus) which is perhaps sheltering a pride of sated lions in the blazing afternoon sun, to yet the even distant hills farthest away. Small apertures provide a huge depth of field bringing everything into focus allowing you the opportunity to tell a story about your scene.
If you haven’t yet invested in a Nikkor or a Canon 50mm f/1.4 then buy one as soon as possible. This lens should be a part of every photographer’s kit. Also, a wide angle lens can help you achieve great story-telling landscapes.
About the Author:
By Cee Dhinjan | http://www.dhinjan.com. Dhinjan.com provides an online photography course teaching beginners the basics of photography and how to use their digital SLR camera manually to take creative photographs from the comfort of their own home. There are several other digital photography techniques and image editing tutorials.
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