Link This |
Email this |
Blog This |
Comments (0)
High Dynamic Range imaging
December 8, 2007
A technique that has become quite popular of late is the process of HDR photography, and it has some potential for both artistic interpretation of images, and the creation of clever photos that would otherwise be impossible. HDR stands for High Dynamic Range. It is a solution to the problem of exposure where the range of light in the scene is greater than the capacity of film – or an electronic sensor – to gather it without overexposure.
With High Dynamic Range photography, the photographer makes a series of photos – typically three – that record the scene in ranges of exposure. One photo records the darkest shadows, the second records the midtones, and the third records the highlights. After the exposures are made, the photographer uses Adobe Photoshop to assemble the series of photos into a single image that has a tremendous range of tonality. HDR requires the subject matter to be stationary, obviously, because things that are moving can’t be recorded easily in three quick exposures.
Once the HDR image is made, it can be enhanced by a process called tone-mapping. This process adjusts the color and tonal interactions in an image to enhance the newly-expanded range of the HDR photo. The results can be extraordinary, and many photographers have adopted the technique.
Weird Al Yankovic, the ever-popular parodist musician, is depicted in HDR on the cover of his latest album
Straight Outta Lynwood. It’s an extraordinary photo.
Weird Al Yankovic's new CD, Straight Outta Lynwood, has an extraordinary image on the cover. I have been unable to find a credit for the photo.
Photoshop guru
Ben Willmore has been driving* the HDR process, teaching photographers around the world about the technique, and the follow-up processes that he uses to create some amazing images.
Ben Willmore's brilliant HDR image of an abandoned gas station on Route 66 is an excellent example of the HDR method, combined with hours of Ben's artistry. It not all done with software! Photo copyright 2007 Ben Willmore, used by permission.
The process is moderately complex. You need a camera with manual controls, a tripod (unless you are careful), and both Adobe Photoshop for the combination of images into an HDR mix, and a complementary application that can do the tone-mapping. Having been under the influence of Mr. Willmore for a while, I have been experimenting with HDR and tone-mapping (I’m a late-adopter) using Photoshop and a program called
Photomatix Pro from French software developer HDRSoft.
My efforts to explore HDR and tone-mapping have reaped some rewards so far. This image of the Fremont Theater would be pretty bland by itself (left). But, with a combination of three bracketed exposures, compositing as an HDR image, some perspective control, and a considerable amount of tone-mapping, I have a pretty terrific image of the theater. The sky is enhanced immensely by the Photomatix Pro software, making the image much more attractive. Click on the right-hand image to see a full-screen version.
This morning, in an effort to take advantage of cloudy skies, I took my camera downtown and photographed our landmark Fremont Theater, an Art Deco treasure in downtown San Luis Obispo. I set my camera to take bracketed sets of exposures which I then combined in Adobe Photoshop, and passed the file to Photomatix Pro for its delightful tone-mapping. Though not nearly as sophisticated as the images created by Ben and others, my results are encouraging. With a bit more practice I am sure I will be hired soon to take the next Weird Al Yankovic CD cover photo.
For another example of really extraordinary imagery that appears to be done using similar techniques, please treat yourself by visiting the online portfolio of photographer
Dave Hill.
* Driving literally and figuratively – Ben lives in a big bus-thing, driving it from city to city where he teaches his imaging seminars.
Posted by Brian Lawler on December 8, 2007 | Comments (0)
