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4 minute read
Apertures and Depth-Of-Field
Adjusting the size of the aperture in your camera’s lens is not just a way of changing brightness, it also controls how much of a scene looks sharp and is in focus – something photographers call depth-of-field.
When we looked at shutter speeds and apertures, we saw how these fundamentals of photography are related. They make a photo brighter or darker by controlling how much light is allowed into the camera, but this is only part of the story.
Shutter speed and aperture also affect how other things look and, in this article, we take a look at how aperture controls one of the most important things in photography: depth-of-field.
Depth-of-field is the distance in front of and behind the point of focus that looks sharp. When we use small-sized apertures (remember, these are represented by large numbers, such as F16 or F22), we get lots of depth-of-field, so the sharpness zone extends a long way beyond, and in front of, where the camera is focused.
Conversely, if we shoot with a large-sized aperture (represented by a small number, like F4 or F2.8), we get shallow depth-of-field, meaning that only a small zone either side of the point of focus looks sharp. Sometimes lots of depth-of-field is needed; other times, we need very little.
© Jonathan Irish
A good way to take control of aperture is by using Aperture Priority mode.
- For cameras with a mode dial. Set the mode dial to A for Aperture Priority. You’ll now be able to adjust aperture using the camera’s rear control dial and a shutter speed is set automatically.
- For cameras with a shutter speed dial. Activate Aperture Priority mode by setting A on the shutter speed dial and any numerical vale on the aperture ring. Shutter speed is set automatically.
Shooting with Lots of Depth-Of-Field
A good example of when we need a lot of depth-of-field is landscape photography. To get everything looking sharp – from horizon to foreground – we need to focus about halfway into the scene and use depth-of-field to cover everything else.
Half press the camera’s shutter release button and you’ll be able to preview how much depth-of-field you’re getting before you shoot a picture. Try it at different apertures and you can see the difference.
A word of warning though: remember that aperture and shutter speed need to be balanced to create the correct brightness. In this case, since we are using a small aperture, we need to use a long shutter speed to let in enough light. But if the shutter speed goes too low, the picture can end up blurred because of camera shake – accidental movement when the shutter is open.
© Alan Winslow
Camera shake usually occurs with shutter speeds under 1/100 sec, so if you see yours dip below this magic limit, try increasing the ISO to bring it back up again. Or support the camera on a tripod so it doesn’t wobble.
Shooting with Shallow Depth-Of-Field
There are plenty of times when we don’t want everything in a photo to be in focus – portraits are a good example. We can make people stand out in a scene by making sure they look pin-sharp, but the background behind them is blurred. We do this by shooting with a large aperture to create shallow depth-of-field.
At this point, it’s worth considering what a large aperture looks like. Apertures are built into the lens, not the camera, so the range of apertures available to you will be different depending on the lens you’re using. The largest (or ‘maximum’) aperture available on a lens is indicated in its name, for instance, the FUJINON XF23mmF2 R WR wide-angle lens has a maximum aperture of F2. A standard zoom like the XC15-45mmF3.5-5.6 OIS PZ has a maximum aperture of F3.5 at the 15mm zoom setting, and F5.6 when set to 45mm.
© Gareth Pon
Try using the widest aperture you have for portraits. If the blurry background effect is too much, then you can always close it down to something a little smaller.
As with so much in photography, the key to understanding and using depth-of-field properly is experimentation. Try shooting in Aperture Priority more often, varying the aperture so you can shoot a few variations of each scene. When you look at your pictures later on, you’ll be able to see the effect that your changes had and learn from them.
Your Next Steps
- CHALLENGE Shoot two pictures, one with lots of depth-of-field and the other with very little. Post your results to social media with the hashtag #learnwithfujifilm. You can also submit your work here for a chance to be featured on our social media channels
- WATCH Check out our video below to learn more about aperture
