Depth of field
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What is depth of field?
Depth of field or DOF is the zone of acceptable sharpness within a photo. This area appears to be in focus. Images with small zones of focus have a shallow depth of field. A large zone of focus is often called a deep depth of field.
Hyperfocal distance is the place to focus on to make sure that everything in the frame is in acceptable focus. It’s often utilized when photographing landscapes that “stretch into infinity”.
What affects DOF?
Depth of field is mainly affected by three factors:
- Aperture
- Distance between subject and camera
If you want to achieve a shallow depth of field, you can use a lens with a large aperture, get really close to your subject, and/or use lenses with a long focal length.
The size of your camera’s sensor also impacts DOF, with full-frame cameras tending to produce a shallow depth of field, while cropped sensors do the opposite.
In practice, it can be difficult to change one, two, or maybe even all three factors. Aperture is often the aspect that’s the easiest to change. You have to experiment and adapt to the situation you find yourself in.
How to calculate depth of field
In order to know the depth of field, you need to account for the three factors above. While it’s possible to mathematically calculate the exact value of DOF, there’s plenty of free calculators out there, like this one.
Most DSLRs also have a DOF preview button. Pressing this will display the image in the viewfinder which will show you how your picture is expected to look like.
Summary
Focus is one of the most crucial parts that affects your images. You can try to keep everything in focus with a deep DOF and create a clear, detailed image of your subject. You can also make them really stand out by separating them from the background with a shallow depth of field, possibly even creating a pleasing bokeh.
