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Tutorial-HDR

How to create a High Dynamic Range [HDR] photograph

by Andrew LeBlanc

Introduction to HDR

A High Dynamic Range photograph is one that is not highly under exposed or over exposed. It is a post processing process that allows us to combine several images to enable more of the image to be properly exposed. If you've ever tried taking a picture of the sky to get a rich blue colour and highly defined clouds you know that it will make most other things in the picture quite dark. The picture loses it's appeal (unless all you're looking for is sky).

Sky is properly exposed Ground is properly exposed

High Dynamic Range allows us to combine these images to get the best of both worlds. In fact, it allows us to combine more than just 2. Sometimes to get the required range of brightness you might have to take up to 7 photographs.

Compare these two images to see the difference that HDR makes


No HDR HDR (5 pictures)
 

Taking the Picures

Best results will be had when using a tripod with your camera in fully manual mode. If you don't have a tripod... find a good sturdy rock or ledge. Since HDR involves multiple shots, you must figure out how many shots to take. One way is to take 5-7 shots and simply adjust the exposure by 1 f/stop in each shot. The second is to determine the brightest part of the shot and the correct exposure to properly expose it, identify the darkest part of the shot and the correct exposure to properly expose it. Then it is only a matter of adding the total difference in exposure compensation and dividing it by the number of shots you want.

A good starting point is to take a picture starting at -3 or -2 then taking one at every f/stop until +2 or +3. I recommend using RAW if your camera supports it.
 



Step-by-step:

  1. Frame your shot
  2. Set your f/stop to obtain the desired depth of field
  3. Focus on the subject in either manual or automatic. Ensure you are in manual focus when complete. This ensures your focus point won't be adjusted by the camera automatically between images.
  4. Select your ISO. The lower the better, use ISO-100 if possible.
  5. Underexpose your image by 3 stops or until the brightest point in your shot is properly exposed.
  6. Take a series of pictures (3 or more) to capture the shadows, midtones, and highlights by adjusting your exposure level by the amount you determined (usually 1 stop is good).
    **Note: If you are taking 3 shots, ±2 or ±3 is a good range.


Examples of a sequence of photographs: