The depth of field within a shot or photo is the zone between the nearest and farthest parts of the image that are reasonably in Image Focus.
Three determining factors:
- Lens Opening
- The smaller the aperture the greater the depth of field. It is *important to remember* that the higher the f stop, the smaller the aperture. Therefore high (like 22) f stop = deeper depth of field and low (like 2) f stop = shallow depth of field.
- Focus Distance
- The farther the Camera to Subject distance, the greater the depth of field.
- focal length
- The longer the focal length of the lens, the smaller the depth of field.
No difinitive formula to calculate depth of field is presented. Refer to the Depth of field charts for specific information.
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*It is important to note* that the depth of field projects back from the plane of focus twice as far as it does in front of the plane of focus. This is called the 1-2 ratio rule.
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For an extremely detailed explaination of this topic, refer to the http://en.wikipedia.org/wiki/Depth_of_field.
