Technical Perspectives on Digital Photography

One of the things shadow/highlight adjustments are useful for is to correct for underexposure in a part of a picture. However this feature seems to get overused (and hence abused) a lot; which results in (what I consider) to be nasty halo artefacts.

Here is an exampe for the kind of picture you may want to jazz up using shadow/highlight:

Now if you run shadow/highlight on this image and realizing you want your sky to be a little darker, get a little too liberal with the highlight processing, you end up with something like this:

The halo-ing at the horizon to me tooks displeasing. However these kinds of images seem to pop up everywhere; especially with people playing around with HDR. Now I wouldn't presume to dictate what is and isn't art, hence I will concede that this type of shadow/highlight 'abuse' could be used to render an image with specific artistic intent.

If you did want to brighten up the shadow region in this image, by being a bit more judicious in the application of highlight processing, we can avoid some of the halo-ing artefact:

Incidentally, the correct answer in such a situation would be to take series of exposures and merge to HDR. Once you have an HDR image, you'll want to convert back to LDR using the appropriate exposure and gamma values that gets you the desired detail in both shadow and highlight regions. However be wary as some HDR->LDR tonemapping algorithms can introduce similar artefacting.