Mastering Photo Sharpness: A Detailed Tutorial
Fundamentals of Focus
Once photos are corrected, and before saving the file, you should focus all the pictures to recover sharpness lost during the correction process or simply to fix any possible blur. This is the basic technique to sharpen an entire photo:
- Step 1: Open the photo and set an appropriate zoom level for focusing. Depending on the photo’s size, use between 50% and 100%.
- Step 2: Once the photo is enlarged, select Filter / Sharpen / Unsharp Mask.
- Step 3: In the Unsharp Mask, there will be 3 settings.
The Amount slider determines the amount of sharpening applied to the photo. The range should be between 50% and 150%. If you set it below 50%, the effect is almost negligible, and if it is set above 150%, you could have problems (depending on the Radius and Threshold settings).
The Radius setting determines how many pixels around the edge will affect the focus. Almost always, 1 pixel is used, but it may be increased to 2, and in extreme cases, up to 4 (Photoshop allows up to 250).
The Threshold setting determines the difference that must exist between the pixels in the surrounding area before it is considered an edge pixel and, therefore, the focus filter is applied. A pretty safe range is between 3 and 20 (3 being most severe and 20 more subtle). If you need to increase the intensity of focus, it may be decreased to 0, but pay attention to the noise that appears in the photo.
- Step 4: The values that need to be adjusted depend on the results you want to get. For now, set Amount to 120%, Radius to 1, and Threshold to 3.
One way to start is with the Radius and Threshold values given in the examples below and then adjust the Amount bar until you are satisfied.
Soft Focus for Certain Subjects
The Unsharp Mask settings would be Amount 150%, Radius 1, Threshold 10. These values are appropriate for images where the subject is of a mild nature, such as flowers, puppies, people, rainbows, and so on. It is a subtle application of focus appropriate for these types of subjects.
Portrait Focus
If you want to focus on nearby portraits, try this setting: Amount 75%, Radius 2, Threshold 3. This applies another subtle form of focus, but with enough enhancement to make the eyes shine a little more and enhance highlights in the subject’s hair.
Moderate Focus
This amount of moderate focus works well in product photos, photos of interiors and exteriors of homes, and landscapes: Amount 225%, Radius 0.5, Threshold 0. This is a good configuration if you need a beautiful and elegant focus.
Maximum Focus
Amount 65%, Radius 4, Threshold 3. This setting should only be used in two cases: The first is when the photo is clearly out of focus, and the second is when the photo contains many well-defined edges, such as buildings, coins, cars, machinery, and so on. In unfocused photos, a quantity of 400% is also often used; it adds some noise, but you can save a picture that otherwise would not be usable.
General-Purpose Focus
This configuration may be a favorite: Amount 85%, Radius 1, Threshold 4. It is often used almost always. It is so subtle that it can be applied twice if the picture is not focused enough the first time it runs, but once is usually enough.
Focus for the Web
The configuration would be Amount 200%, Radius 0.3, Threshold 0, for web graphics that are unfocused. When you convert a photo of 300 dpi to 72 dpi, they are usually a bit out of focus. If the effect is not too strong, set it to 400%.