If you’re a landscape photographer or even someone who occasionally dabbles in landscapes, you likely already understand the difficulties present in high contrast scenes. As you’re aware, cameras are not capable of recording a scene the same way you see it with your eyes. For example, if you are looking at a sunset, you are capable of seeing the full range of detail in front of you.
Unfortunately, the contrast ratio between a bright sky and a dark foreground will often go well beyond the capabilities and dynamic range of your camera. In jpeg mode, your camera is designed to record images in the manner of color negative film. This means that the image you see on your LCD reveals between three and five stops of exposure latitude. If you shoot in Raw (and you should) you will, of course, have access to the full dynamic range that your particular camera sensor is able to capture. This makes it possible for you to manually adjust an image in post-production so that the full dynamic range available to you is present in any given image.
However, this process is not infallible, nor does it come without acquiring a dedicated skill set.
This is where two particular techniques for landscape photographers come into their own. They are High Dynamic Range (HDR) and the use of Graduated Neutral Density filters (GND filters). The point of both of these techniques is to reduce the contrast ratio in parts of your scene so that the detail in your image more closely resembles what you saw with your eyes.
What is HDR?
High Dynamic Range is a technique that blends multiple exposures together in post-production. The idea is that you create a series of images where each accurately exposes an individual part of your scene. For example, your first frame will be taken to correctly expose the foreground and the second frame will be taken to correctly expose the sky. You then blend these images together using specialist software (often Photomatix or Lightroom).
The most common way to get a set of exposures to blend is to use the bracketing tool in your camera at a 1 or 2 stop interval. For example, if you take an exposure based on your camera’s meter, you could then take three bracketed exposures one, two and three stops overexposed, followed by another set of bracketed exposures one, two and three stops underexposed. This would give you seven exposures to blend.
What is a Graduated Neutral Density (GND) filter?
Graduated neutral density filters achieve similar results at the time of capture. These filters are designed to block a certain amount of light over parts of your image. They come in different strengths, but the most common are the 1-stop, 2-stop and 3-stop varieties. Fitted to the front of your lens with an adaptor, they allow you to control the contrast ratio and dynamic range in your image as you create the image.