In this tutorial, we will show you how you can restore fine details and micro-contrasts to the images you take with lenses that lack sharpness.
As used in photography, sharpness describes the capacity of a lens to reproduce fine details and micro-contrasts. Sharpness is closely related to the quality of the lens manufacture and to the materials used in its design. It also depends on aperture: at maximum aperture, a lens will generally be less sharp than at smaller apertures. Finally, sharpness tends to be irregular across the field, with the central area frequently sharper than the edges.
The visual impression of an image being in focus is created by contour accuracy. In digital photography, contour accuracy is dependent on the quality of the lens used, the sensor resolution, and the focus. Lack of sharpness in an image is usually due to poor focusing during shooting —whether through photographer error or because of a poorly-calibrated autofocus.
DxO Optics Modules
Among other things, DxO Optics Modules correct lens softness for each camera / lens combination. Based on precise laboratory measurements across the entire image field, the modules improve the sharpness of each individual pixel. When you open an image, if DxO Optics Pro supports your lens, the software automatically recovers lost details, homogenizes the sharpness from the center of the image to the edges, and adds micro-contrasts to lend more life to your photos.
To follow this tutorial, you will need:
DxO Optics Pro, Standard or Elite Edition (depending on your camera).
An image in RAW format.
DxO Optics Pro can automatically improve the accuracy of your images by using the appropriate settings to produce the best results. In the first part of this tutorial, we will see how to globally modify the sharpness of your image in case it seems too strong or weak to suit your taste.
1.1 - Open an image and install a DxO Optics Module
In the Organize tab, select the image from the folder in which you saved it (or drag and drop the image onto the DxO Optics Pro window). DxO Optics Pro automatically checks if there is an Optics Module available to use with the selected image. If the module is not already installed on your computer and if you have deactivated automatic module downloading, click on the icon marked with a red arrow at the top right of the image thumbnail in the Image Browser.
In the window that opens on your screen, select the module that corresponds to the camera/lens combination you used for the shot and then click Next. The module is downloaded and installed on your computer (an internet connection is required).
Click on the Customize tab and open the DxO Lens Softness palette.
The palette is composed of three sliders:
The Global slider lets you sharpen the overall image; its default setting is –0.50.
The Details slider lets you accentuate image details; its default setting is 50.
The Bokeh slider protects the gray or blurred areas outside the focal plane from acquiring artifacts during the sharpening process.
To properly visualize sharpness corrections, you will need to work on an image enlarged to 100%. This way you will be able to clearly monitor the effects of the sliders.
1.2 - Adjust the overall sharpness
A careful look at our image reveals that the fine details have not been correctly rendered. Activating the DxO Lens Softness tool automatically sharpens the image right at the outset. To reinforce this, and to bring out the fine details of the roof and chimney, we moved the Global slider to the right (to diminish the effect, we would move the slider to the left). Here we have set the slider to 0.80.
1.3 - Adjust the fine details
It is possible to improve image sharpness using the Details slider, which extracts and enhances details by increasing micro-contrasts. In our example, we have set the Details slider value to 80, which brings out the slate roof tiles as well as the sculptures.
This effect should be applied with caution, depending on the subject. It is particularly useful for sharpening highly-detailed landscape and architectural photos. On the other hand, it should not be used for portrait photography because of the risk of bringing out small skin defects or blemishes.
1.4 - Preserve the bokeh
Sharpening an image can create artifacts in the blurred background of an image. The Bokeh slider helps you protect these areas.
In this example, we have deliberately chosen exaggerated settings: after setting the Global and Details sliders to their maximum values, we have set the Bokeh to 0 for the left-hand image, and to 100 for the right-hand image. Numerous artifacts are visible around the rivet head, the concavity and contours of the red lock, the edges of the padlock, and the small white patch in the center of the left-hand image. But the artifacts have essentially disappeared from the image on the right.
DxO Optics Pro runs in a non-destructive mode, meaning that sharpening is applied to output images after they are exported.
Now we will take a look at how we can make an image more uniformly sharp when a DxO Optics Module is not yet available for a particular camera/lens combination. To do so, we will use the Unsharp Mask tool.
Open the Unsharp Mask palette, which is composed of four sliders:
The Intensity slider, which lets you sharpen the entire image.
The Radius slider, which lets you fine-tune the amount of sharpness to be applied.
The Threshold slider, which allows you to bring out contours without affecting the flat surfaces and details within the contours.
The Edge Offset slider, which acts on the periphery of the image to balance the sharpness of the edges with that of the center.
2.1 - Adjust the overall sharpness
In this step, we will work on the overall sharpness of the image. The more we move the Intensity slider to the right, the sharper the image becomes. In our example, we have set the intensity at 200, which lends greater relief to the details such as those found in the chandelier or in the wooden sculptures in the background. We have left the Radius and Threshold sliders at their default settings (0.50 and 4, respectively).
2.2 - Sharpen the edges of the image
Lenses generally produce images that are less sharp along the edges than at the center. The Edge Offset slider very efficiently compensates for lens softness along the perimeters to create a more uniform sharpness across the whole image. The effect is quite subtle even at high values, which means that the image will not be degraded by the appearance of artifacts or halos.
We have taken the same photo as in the previous step, but this time we have positioned ourselves in the lower right corner. The view on the left shows the result after the previous step’s enhancement, and the view on the right shows the result after setting the Edge Offset slider to 200.