A friend of mine just pointed me to some of the amazing work that’s going on right now in relation to High Dynamic Range Imaging (HDRI). Needless to say, I was intrigued and decided to take a couple photos and give it a shot.Before I describe how I shot and prepared this photograph, let me see if I can give a quick and dirty description of what’s going on here.
Typical cameras (both analog and digital) only have a certain dynamic range they can describe–meaning there is a fixed range between the brightest white and the darkest black. In the real world the ratio of light to dark looking with our eyes is often 10,000 to 1–we perceive the brightest portion to be 10,000 times brighter than the darkest. However with cameras, and especially digital cameras, you’re lucky to capture a dynamic range of 4000 to 1. In practice you might only get a dynamic range of 2500 to 1. With HDR, you theoretically have an infinite dynamic range (really limited only by the device you’re using to display the image).
As a result of this limited ability of cameras to capture the full dynamic range of a scene, most photographs we see never show everything that our eyes can see. Think of taking a birthday photograph at night on a restaurant patio. With the flash from the camera, you’ll probably get all the people properly exposed, but you probably won’t be able to see much else in the background (and the picture won’t generally look exactly like you remember it). Imagine if you could see all your friends, the people at the next table and the cars and businesses across the street. HDR can deliver that experience in a single photograph. Now let’s see how this was done.
So with this photograph of the lovely French Cottage Motel in Hollywood, California I have made a sample HDR image. Now keep in mind, I used a Sony PD100 video camera for this shot. It shoots images at 640×480 (extremely low rez and very poor quality). At the top, you see a typical digital camera photograph. Very little detail is visible in the shot. Anywhere you see a shadowed area, you generally lose some detail. At the bottom, you see the HDR image which was created with 8 separately exposed photographs–ranging from extremely dark (underexposed) to bright (overexposed). Then I used a really cool application called Photomatix to combine the images together and then adjust the tone of the photographs to create a single image and encapsulated the full range of exposures.
Here are a few areas to look at when you examine the image more closely (click the image for the full size version). Take a look at the level of detail underneath the street lamp at the curve of the sidewalk. There are spots and texture in the final image that you can’t even make out in the single image. The leaves on the trees are visible and detailed no matter how bright or dark they appear in the original. And the street has taken on a very shiny texture that even my eyes didn’t pick up because of the glare from the low sun in the sky. You can even make out the few remaining bulbs in the motel sign that were lit up.
I’m by no means an expert on this subject, but I found it really simple to create this image with a crappy digital camera and a cool piece of software. I can’t wait to try this with a better camera and a better subject (though I do love the seediness of the French Cottage). The poor French Cottage: it’s probably going to be “scraped” soon to make way for another ugly strip mall, so I’ll put this photo in the time capsule for future generations to enjoy.