High Dynamic Range

Creating and saving a camera curve profile

When using High Dynamic Range to optimize photos from a certain camera, you first need to select an existing or generate a camera response curve for your camera. (A camera response curve indicates how the camera's light sensor responds to different light intensity levels.) A camera response curve must be saved as a camera curve profile if you want to optimize a single-shot photo or a photo of a subject photographed in motion.

Tip: If you only have one photo of a particular scene and you don't have a camera curve profile for your camera, you can use one of the camera curve profile presets to create the HDR image.

To be able to create an accurate camera curve profile, the image shots that are used as basis to create the camera curve must show all the highlights, details, and shadows of the photographed scene. Here are some guidelines on how to set your digital camera when photographing the image shots:

• Mount your camera on a tripod and set your camera to aperture priority to shoot photos at a fixed aperture with varying shutter speeds.
• Take at least three shots (five shots or more is recommended) of the same scene with different exposures.
• To capture large exposure differences when taking fewer shots (such as three to five shots), set the exposure in increments of at least +/- 1.0 Exposure Value. Whereas if you are taking a greater number of shots, you can set the exposure at lower increments but make sure that the number of shots are enough to cover a wide range of exposure levels.

1. Open the photos that were taken using various exposure levels.
2. Select Photo: High Dynamic Range.
3. In the Composition tab, select Auto generate camera curve from the Camera curve profile choices.

   NOTE: If your photos retained the EXIF data recorded by the digital camera, the F-stop interval can automatically be determined based on the exposure time stored in the data. Whereas if your images are non-EXIF images, you need to manually specify the F-stop interval between your images.

   
   
4. Click Save as button to save the camera curve profile.

   NOTE: If you used your camera's Automatic Exposure Bracketing feature and took two (or more) sets of shots, some photos will have the same shutter speed and exposure time settings. A message appears when photos have identical settings. In the Image List Panel, click [-] to remove these photos.

   
   
5. Click the Compose button to create an HDR image using the generated camera curve.

   Tip: PhotoImpact includes preset camera curve profiles for some digital camera models. If there is a camera curve profile available for your camera, you can directly use it for your photos.

Composing an HDR image using multiple images

Create an HDR image by combining photos that have different exposure levels. Before composing the HDR image, you can also choose to fix differences between the different photos to eliminate blurred areas when the HDR image is composed. After composing the HDR image, you are automatically taken to the Optimization tab.

1. Open the photos that were taken using various exposure levels.

Tip: At least one image with EXIF data is required for creating an HDR image.

2. Select Photo: High Dynamic Range.
3. In the Composition tab, select the Camera curve profile of the camera you used to take the photos.

Tip: If your photos are handheld shots, select Auto crop after registration in Registration and click Apply to merge them and remove excess white space from the merged image.



4. Select Remove artifacts to fix differences in your photos before they are combined to compose the HDR image. Select whether to use Auto or By Brush to designate areas in the photo that you want retained or removed.

   NOTE: Remove artifacts is not available when you only have one image opened.

   
   
5. Click Done.
6. Click the Compose button to create the HDR image.

The program then automatically brings you to the Optimization tab.