Defective pixels which are permanently ‘off', and show as dark dots in the image. This should not be confused with light-shielded black pixels, which line the peripheries of a sensor and are used to monitor dark current.
On sale: 29th Aug
Highlights this month include your essential guide to using prime lenses, plus 36 tips for better landscape images in our brand new 12-page Technique series, and we help you take control of your ISO settings. Plus much more!
Which of the new cameras announced so far this year are you most excited about?
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