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Even with the best lens and camera, you might capture photos where the main subject appears soft, mainly if you use autofocus when shooting in poorly-lit interiors. Photoshop is sophisticated and versatile and includes filters such as Unsharp Mask and Smart Sharpen that can help you sharpen your images.
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The most common filters you can use to sharpen your photos in Photoshop are the Unsharp Mask and the Smart Sharpen. These two filters are closely related, and even the procedure of opening them is generally the same.
For instance, you can pick these filters by navigating to Filter on the top menu, choosing Sharpen, and then selecting Smart Sharpen or Unsharp Mask. However, these filters use different algorithms to manipulate your image, and understanding how they differ can help you choose which one to use for your photos.
Unsharp Mask (UM) is a sharpening filter in Photoshop that works by applying a Gaussian blur to a copy of the initial photo and then automatically comparing it to the original photo. Usually, if the difference between the two images is more significant than the one you specify, the images are subtracted.
That means this filter doesn’t detect the edges of objects in the photo as many think. Instead, it compares the pixel values with the neighboring pixels. If the values differ by a given amount, it increases the contrast along the edges by a set amount, making the image sharper.
The Smart Sharpen (SS) filter works similarly to the UM filter. However, it’s a more advanced sharpening filter that allows you to choose whether to apply the Gaussian, Motion, or Lens blur.
The filter compares neighboring pixels, and if the difference meets the specified values, it increases them. Typically, this makes darker pixels darker and lighter pixels more light. This increases the contrast along the objects’ edges, making the photo sharp and detailed.
Keeping in mind that both filters use the same principle of comparing the pixels and increasing the contrast, they have similarities in their functionality and results. However, they are different filters with different settings, making each suitable under certain conditions.
Although the two filters use different algorithms to add contrast to the objects’ edges to make a photo detailed and sharp, they share the following features and usability similarities.
As the name suggests, the Amount option controls the level of adjustments or the magnitude of the effect. The amount option lets you set the extent to which the filter will increase the contrast.
Since the two filters are versatile, they both come with an Amount slider that lets you set the amount of sharpening you want. The setting is in the form of a percentage, and you can adjust it from 0% upwards.
Although this is a percentage, you can increase the values to above 100%, such as 500%. However, note that a high setting will cause the border to be so defined, and the photo might not look natural. If you aren’t sure of the right settings to use, both filters come with a default setting of 50%, which you can start with.
Since the contrast increase occurs between neighboring pixels on different sides of the grayscale, it’s normal for some kind of a border that defines the contrast to appear. However, since this is not natural, and you are creating it through edits, Photoshop allows you to adjust its thickness.
In both filters, you can adjust the thickness of this border using the Radius setting. However, unlike the Amount, the filters allow you to adjust the border's thickness by defining the number of pixels you want to include in the border.
Keeping in mind that the grayscale runs from 0 to 255, with 0 being black and 255 being white, the middle of the scale, which is around 128, forms the mid-tones. That means Photoshop takes the pixels less than this value as blacks and the pixels more than this value as whites.
Since the two filters make the light pixels lighter and the dark pixels darker, they don’t affect the mid-tones. That means the two filters can’t sharpen an image so soft or blurred that there is no contrast.
Keeping in mind that these are distinct filters that use different algorithms to detect the contrast and increase it, they have the following differences in their flexibility, versatility, and settings you can use to sharpen the image.
The image noise is the graininess effect that makes a photo look pixelated and low-quality. In most cases, this effect results from taking photos with a low-end camera or using higher ISO settings to brighten images when capturing real estate photos in dark interiors or using fast shutter speeds.
Although this effect might be minimal and unnoticeable, when you use the sharpening tool to make the darks darker and the lights lighter, the noise also tends to increase to visible levels. The noise reduction feature helps reduce the effect and makes the photos smoother and of better quality.
Typically, the Unsharp Mask filter doesn’t have this feature, while the Smart Sharpen filter comes with this feature, allowing you to reduce the noise as a percentage.
The UM filter comes with a threshold feature that allows you to choose how different the pixel values need to be before Photoshop increases the contrast. Typically, this allows you to ignore the areas with minimal contrasts and only add contrast to areas with significant contrast.
The control is intuitive, as you set it using a slider. On the other hand, the Smart Sharpen filter comes with the less precise Remove feature, which allows you to set an option of either the Gaussian, Motion or Lens blur.
The main distinguishing factor between UM and SS is the Shadows and Highlights feature. Depending on the photo you are editing, setting a high amount can introduce a bright line in high contrast areas, commonly known as halos.
Typically, this means the darkest edge becomes pure black, and the brightest edge becomes pure white. Unlike the UM, the Smart Sharpen filter comes with the Shadows and Highlights feature that allows you to fade the sharpening and reduce the halo effect, making the contrast look more natural.
Since UM contains fewer settings and allows you to adjust all the settings as sliders, it’s the best filter to use in the following situations:
Keeping in mind that the SS filter is more advanced and comes with features that can help remove image noise and halos, it’s the best filter for sharpening images in the following circumstances:
The SS filter is better for editing real estate photos as the resulting images look natural and realistic without hard-defined edges. The noise reduction features also allow you to get smoother and more high-quality images. However, if you want simplicity, you can use the UM filter.
The above Unsharp Mask vs Smart Sharpen guide reveals the strengths and weaknesses of each filter, with the former being easier to use and the latter resulting in more natural and precise edits. However, both filters are versatile, and you can use them interchangeably.
