Exposure Challenges


Today’s Question: How do you expose for scenes with bright sky and darker land if you don’t use a variable ND [neutral density] filter?

Tim’s Quick Answer: For high contrast scenes I prefer to use bracketed exposures that I will later blend into a high dynamic range (HDR) image, rather than using a graduated split neutral density (ND) filter.

More Detail: It is somewhat common to have a situation where there is a wider range of tonal values in a scene than a camera is able to capture in a single normal exposure. That means that without dealing with the high contrast in some way, you’ll end up with a photo that has lost detail in the highlights, in the shadows, or both.

There are two basic ways you can overcome this issue. The first is to use a graduated split neutral density filter. This is a filter that is darker on one side and more clear on the other side, with a smooth gradation in between. This type of filter enables you to hold back some of the light for the bright sky, for example, while not holding back any of the light in the darker foreground.

The problem with a graduated split neutral density filter is that the gradation often won’t provide an appropriate transition for the foreground versus the sky. For example, if you have a tree or other object extending above the horizon, the top of the tree would appear darker than the bottom of the tree due to the effect of the graduated filter. That can look rather artificial and distracting in the photo.

Instead, I prefer to create a high dynamic range (HDR) image in situations like this. I simply make use of automatic exposure bracketing (AEB) with two stops of separation between the individual exposures in the sequence. I can then assemble those bracketed exposures into a single image representing the full tonal range of the scene, using software such as Lightroom Classic, Camera Raw in Photoshop, or Aurora HDR (https://timgrey.me/aurora). This approach provides much greater control and flexibility compared to the use of a graduated split neutral density filter.