First, you shoot three images of an object/setting at -2EV, 0EV, +2EV. Use a tripod.
After you’ve shot the three images and download them from your camera to computer, there are three simple steps to follow to get an HDR photo in Photoshop CS5.
1. Navigate to File>Automate>Merge to HDR pro.
2. Browse your hard drive for your picture files, Click OK.
3. After a few minutes the merge to HDR window appears with sliders to make adjustments in the image.
After you’ve adjusted the sliders, you hit Enter and Photoshop goes to work processing your image.by