Photoshop Tutors

One Response to “What is HDR photography? and how does one do it?”

1. Mai
   August 2nd, 2008 at 6:09 am

   Most digital cameras are only able to capture a limited dynamic range (the exposure setting determines which part of the total dynamic range will be captured). This is why HDR images are commonly created from photos of the same scene taken under different exposure levels.
   Here some recommendations for taking the Low Dynamic Range input images for the HDRI:
   1. Mount your camera on a tripod
   2. Set your camera in manual exposure mode. Select an appropriate aperture for your scene (e.g. f/8 or less if you need more depth of field) and the lowest ISO setting.
   3. Measure the light in the brightest part of your scene (spot metering or in Av mode to point only the highlights) and note the exposure time. Do the same for the darkest shadows of your scene.
   4. Determine the number and value of exposures necessary. For this, take as a basis the exposure time measured for the highlights. Multiply this number by 4 to find the next exposure with a stop spacing of 2 EV. Multiply by 4 successively for the next exposures till you pass the exposure measured for the shadows. (Note: For most scenes, 3-4 photos should be sufficient to cover the dynamic range).
   5. You can make use of auto-exposure bracketing if your camera supports it and if it allows a stop spacing of 2. Otherwise, just vary the exposure times manually.

   Once your differently exposed photos are taken, go to “Generate HDR” on the HDRI menu of Photomatix, load the photos and click OK. This will create an HDR image for your scene.
   Photomatix lets you save the HDRI under 3 different formats: Radiance RGBE (.hdr), OpenEXR (.exr) and Floating Point TIFF. See Greg Ward’s HDR Image Encodings page for an excellent overview of HDR formats.

   you will have to purchase software to convert your images to High Dynamic Range photos…..enjoy!