Landscape Photography Mistake No. 8: Obvious graduated ND filter use
Using the image combining technique to record detail in the sky and the land avoids a problem that dogs the use of ND filters; working out where to position the transition section of the filter so that it goes unnoticed.
Unfortunately any objects that extend into the sky, such as trees, buildings or even ills and mountains, will have a noticeable exposure change along their length.
This problem is hard to disguise even with neutral density filters that have a soft gradation, so digital techniques offer a helpful alternative provided that the photographer is careful with the selection or masking when combining the images.