Optimizing Dynamic Range

For those of you who don’t know what Dynamic Range is, I’ll try to sum it up in a sentence. Dynamic range is the amount of detail we can capture between dark and light. On average Digital SLR cameras capture about 9 stops. A good example of seeing it in action is to take a photo of a sunset. Your photo will either have a black foreground or a white sky. With today’s technology it isn’t possible for Cameras to capture the world as we see it with our eyes. The human eye can see about 16 stops of Dynamic Range which is in a whole other league compared to today's Cameras.

There are many ways of balancing the exposure so that it will fit inside the dynamic range of your camera. The first method is probably the oldest and involves using graduated neutral density filters (GND). These filters need to be bought with a filter holder in the size of the lens you intend to use them on. This is most likely the most expensive way to optimize your exposure but it saves you the trouble of doing it with software.

The second way to get a balanced exposure is to use a tripod when taking your image. You will now need to take a photo with the correct exposure for the sky and another for the foreground. We can then combine these photos in Photoshop or any other software that allows you to layer different images over each other.

You can also cheat a little bit and use just one good exposure for both like in this example. Note that this only works well with RAW files and isn’t recommended for jpg’s. Here I converted the original Raw file as shot to Jpg and then boosted the exposure by 1 stop to get the foreground to match the sky more evenly.

Now we need to open both these Images in your editing software and apply a gradient mask over them.

As you have probably noticed all of the above techniques only really work when you have a clear horizon. The second you have a tree breaking that line it will almost always be transformed into a silhouette. There is one way to get around this and that is by using what we call High Dynamic Range (HDR). There are many popular software titles that allow you to make HDR images. I personally use Photomatix since it is one of the first and still gives the best results. You can however create some disastrous images with it if you aren’t careful. I am not a real fan of those super unrealistic HDR images and usually go for a more realistic look. That is why I use the exposure fusion instead of HDR tone mapping in Photomatix.

Conclusion

HDR Software or manual blending with the right shooting technique can be more versatile and provide you with better images than normal filters. If you don’t already own any filters I highly suggest you try the software route first before spending any money on filters. In the end you need to decide whether you have the extra space in your bag and if those filters are worth the time saved getting it right in the camera.