Lens Sharpness: creating evenly sharp images
What is Lens Sharpness?
Sharpness, which is also known as acutance, refers to how crisp an image appears. In a photo with sufficient sharpness, you’ll be able to see even the smallest details as well as any micro-contrasts. This characteristic is closely related to the manufacturing quality of your lens and the materials used in its design. It also depends on the settings used to shoot the photo, including the aperture of the diaphragm, focal distance, and focal length. Sharpness is not applied evenly to the entire photo. The central area is often sharper than the edges.
Even without any motion blur, a properly focused photo can appear blurred if the lens is not sufficiently sharp.
- Camera: Nikon D4
- Lens: AF-S 24-70mm 2.8
- Parameters: 27mm f/7.1, 1/250, ISO100
- Correction optique DxO
A significant measurement for over 100 points in the image
DxO goes beyond the standard modulation transfer function (MTF) measurements to produce a perceptual measurement of image sharpness. For each aperture and focal length combination, perceptual blur is estimated using a single BxU (blur experience unit), resulting in a significant measurement for 121 separate points in the image. The aperture setting is used to correct the sharpness and compensate for lens diffraction.
DxO superimpose a model on a BxU map to provide the BxU measure function for every position in the image.
A correction directly applied to the RAW or JPEG file
Unlike ordinary sharpness improvement tools, DxO’s methods directly affect both RAW and JPEG files. This allows DxO to use the best version of the image before applying other settings or modifications. Any lack of sharpness is evenly corrected across the entire image by precisely adjusting how much this parameter is improved. The result is an evenly crisp photo.
DxO’s sharpness improvement algorithm also recognizes homogeneous and blurred areas. Rather than degrade the quality of these parts of the image, they remain soft.