High Dynamic Range

HDR or High Dynamic range is accomplished via multiple photos bracketed to capture different dynamic ranges, and then combined as one photo in photoshop.

The following techiniques will give you a starting point, but you will want to experiment with the degree of bracketing, 2-4 stops and then see the resulting image.

 

Step 1.

Set the bracketing on camera to 2 stops. Then set the shooting mode to burst.  Hold the shutter down, 3 photos will be captured.  Shoot in RAW mode for the widest possible dynamic range. You can still create HDR if your camera doesn’t support RAW. Make sure you shoot in Aperture Priority or in Manual. You want to bracket the exposure time, not the Aperture. If you change the aperture, the depth of field won’t be consistent and you’ll get blurring. Also avoid any moving subjects in the photo or you’ll get ghosting.

Step 2
Import photos to your computer

Choose File>Automate >Merge to HDR. This works on Photoshop CS2,CS3,CS4. Choose folder. Organize each set of photos in its own folder. Select your photos to merge. Turn on Auto Align in Photoshop CS3. Click OK. Photoshop CS3/4  uses new Auto-align technology that even allows you to create HDR without the use of a tripod!)

Step 3
Your images will now be merged into a single photo. You can turn off individual photos by un checking their boxes on the left filmstrip. If you get some blurring caused by camera shake in the longest exposure, you may want to turn off that photo.

Step 4
The merged result is a floating-point 32 bit image. You can adjust the overall tones by sliding the White Point slider.

Step 5
Click OK to merge the photos into a 32 bit image. Now is a good time to save your file.

Step 6
In order to use the photos, you’ll need to convert them t 16 or 8 bit images. When we convert them we will create what I call interpretations of the photo. The reason I say this is because we have unlimited ways we can make the photo look. While we have this huge dynamic range available in 32 bit, we will no longer have those options after conversion. Always work from the saved 32 bit version, and then convert and save versions (personal interpretations). Avoid overwriting the 32 bit image, it’s our master and we may want to go back to it many times.

Choose Image>Mode>16 bit (or 8 bit). Now we get to play with some fun options. You’re now at the tone mapping part of the process. This is were all the creativity can ooze.

(If you want to make the adjustments without converting, choose view>32 Bit Preview Options. You can use several of Photoshop’s tools in the Image>Adjustments menu. The most important of these is the Exposure control)

You’ll see an HDR Conversion Dialog box. Exposure and Gamma is the default option. Best way to approach this? Set the gamma first, then adjust the exposure to suit. If you want an image with lots of contrast, lower the gamma. For less contrast raise the gamma. Finally, adjust the exposure to get the desired brightness. If you want more control, read on… otherwise press OK to convert.

Voila, you have your first HDR image. Now experiment around and see how much more The HDR image shows over a single photograph.