Today’s Question: There is an article in Outdoor Photographer posting Monday about “Mastering the Grad ND” filter. With the capabilities in Photoshop/Lightroom (specifically the Gradient Filter tool), is there a substantial difference in using the filters over creating the same effect in post?
Tim’s Quick Answer: In general I would say that I consider the graduated neutral density filter to be obsolete. The various options for applying graduated adjustments provide an alternative for many situations. And when the dynamic range of the scene exceeds the abilities of your camera, capturing multiple exposures to blend into a high dynamic range (HDR) image is generally a better solution compared to the use of a graduated neutral density filter.
More Detail: One of the frustrations of working with a graduated neutral density filter is that it is graduated in a linear way. Many real-world scenarios prove to be a challenge with a graduated neutral density filter, due to a foreground subject extending above the horizon. Such an object will be darkened toward the top along with the sky, creating an obvious clue that a filter was used for the photo.
In situations where a graduated neutral density filter provides a minor advantage, a gradient adjustment in post-processing can often provide a similar (or even better) adjustment. For situations where a graduated neutral density filter is not a great solution, a graduated adjustment in post processing will also prove challenging.
However, you can produce a superior result in many challenging situations by simply capturing multiple exposures and combining those into a single high dynamic range (HDR) image.
In short, I never employ a graduated neutral density filter in my own photography. If the dynamic range is not beyond the capabilities of my camera, I can simply capture a single exposure and then apply a targeted adjustment when processing my photo.
For situations where the dynamic range of the scene exceeds the capabilities of my camera, I will capture a sequence of exposures that I will blend together into a single high dynamic range (HDR) image in post-processing, producing a better result than I could have achieved with a graduated neutral density filter.