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This high-ISO indoor shot demonstrates some common sharpening dilemmas

Intensity

A simple Intensity adjustment is often all you need to give the fine detail in your shots valuable extra crispness, but there is a price to be paid, especially with images shot at higher ISOs. An Intensity of 50% makes this ISO800 picture sharper, but it really brings out the noise, too.

Radius

The default Radius value of 5% is usually just about right, but for shots with more blur or focus issues, a higher Radius can help disguise the softness. But watch out – see how this higher Radius value has created edge effects (haloes) around objects and made the tones much harsher.

Threshold

The secret is to stick to relatively low Radius values and use the Intensity slider to boost sharpness. If noise becomes an issue, use the Threshold slider to control it… but, again, stick to low values. High settings will leave you with harsh edges and smoothed-over detail in between.