Today’s Question: In [Adobe Camera Raw or] Lightroom, can the sharpening sliders in the Detail panel be used in conjunction with the Clarity and Dehaze sliders, or should I (in general) use one just one of these tools on any particular image?
Tim’s Quick Answer: Sharpening, Clarity, and Dehaze focus on different issues, and therefore you can indeed mix and match all three depending on your specific goals for a given image.
More Detail: There is no question that the Sharpening, Clarity, and Dehaze adjustments in Lightroom and Adobe Camera Raw (as well as similar adjustments in other software tools) provide effects that are all similar. However, the differences among these adjustments are such that there is no problem employing more than one (or even all three) of these adjustments for a single image.
In a very general way, you can think of all three of these adjustment types as providing a localized contrast enhancement. All are, in varying degrees, enhancing contrast in areas of the image that already exhibit some degree of contrast in the way of texture and detail.
The key difference between these three adjustments is the scale, especially in the context of the Sharpening and Clarity adjustments. Sharpening applies at a very small scale, mostly emphasizing differences between immediately adjacent pixels. Clarity is very similar, but with a somewhat mitigated effect that blends across larger transition areas within the image.
The Dehaze adjustment can to some extent be thought of as being very similar to the Clarity adjustment, conceptually applying across an even larger transition size. However, the Dehaze adjustment is actually quite a bit more sophisticated than that.
The point is that while there are considerable similarities among these several adjustment types, the differences are such that you can indeed use all three (as needed) for a single image. Sharpening will enhance perceived sharpness, Clarity will help enhance texture, and Dehaze will help reduce the appearance of haze. All similar effects to be sure, but with a different specific implementation in each case.