Fraser River and HDR software

The Fraser River during fall; modified using HDR software

HDR stands for High Dynamic Range.  Dynamic range is the amount of light, measured in stops, which a medium can represent in an image.  A typical JPEG has a dynamic range of about 8, meaning that it can represent shades of light to dark over about 8 stops.  A stop is a doubling or halving of light.  This is near the low end of dynamic range; it can capture a lot of different tones but really bright or really dark parts of a scene will have no details in them.  They will either be totally black or totally white.

If you notice the sun is behind the tree.  There are white clouds and a bright reflection coming off the water.  Then there are dark parts to the image.  The tree is backlit and there are shadows under benches and from the trees on the left.  The range of shades is far greater than 8 stops.  A camera typically records images in the forms of JPEGs and cannot possibly capture the huge range of light present.  Switching over to RAW mode, if a camera has it, will usually allow you to gain a few stops of dynamic range, moving upwards towards 12.  This will allow the photographer to capture the greater range of lights and darks showing details in places a JPEG cannot.

If you want to go beyond the RAW capabilities of your camera, you have to use HDR.  Some cameras actually have an "HDR" feature built into them, but I have never found them all that useful.  Typically they allow you to shoot only two images and the quality of the final processed image is typically poor.  The shot above consists of eight photos, each taken a stop apart.  The images were combined using a computer program (Photomatix) designed specifically for working with HDR pictures.  I have tried using Photoshop's (CC and CS) HDR processing algorithms but have found it insufficient for the job.

What I like about the proprietary application is that the final file can be manipulated in may different ways.  The exact nature of the shot can therefore be changed dramatically, going from real to surreal or from morbid to splendid.  In order to do a good job on it though there are conditions.  A tripod is a must so that each image is identical in terms of framing.  You can't have movement in the scene; people, vehicles, wind, and waves all cause ghosting which can be a problem.  You will be taking quite a few shots to compile ultimately into a single image, so there is the issue of storage space.  The person has to be able to adjust their camera using exposure compensation or manual mode, and they have to have a computer with the right software available.  Then you have to know how to use it.

HDR is very interesting and can be fun, but it usurps quite a few resources.  Having said that, you can do some pretty cool things with it.  The above photo is not realistic, but it is definitely captivating.  HDR many not be for you, but at least now you know a little more about it.