Canon® EOS Digital Photography Photo Workshop

5.9. VIGNETTING

When light falls off of the edge of a photo, the periphery of the image is darker than the center, which is called vignetting. Essentially, light diminishes as distance increases from the optical axis, especially toward the corners of the image. This can be done on purpose as an artistic effect, such as in 5-11, or it can be the result of optical issues with your lens.

Many lenses have some natural or optical vignetting depending on their focal length and, if they are zoom lenses, to what extent they are zoomed. While often very minimal and virtually unnoticeable, the effect is more pronounced with fully extended zoom lenses. It is even more likely if you're using a converter with the lens. In these cases, you might see darkening in the extreme corners of the image.

Mechanical vignetting can result from improper lens attachments that incorrectly place optical elements so that they cannot fully transmit light to the image sensor. This can happen, for example, if you place too many filters on the lens or if you have a lens hood that's not suitable for the lens. Often this type of vignetting effect is much more abrupt, while a natural vignetting is more gradual.

Figure 5-11. This image has a vignette effect that is typical of poor-quality lenses when used at full zoom. This example is simulated. ©Serge Timacheff

NOTE

Many image-editing programs have options to help ...