December 15, 2007

HDR Travel Photos
Lima, Peru

High Dynamic Range (HDR) images are a new style of photography for me, and I'm quickly falling in love with the possibilities can do for imparting a greater sense of accuracy and emotion in my photography.

Chances are good that if you were taking photos before the turn of the millennium, it was with film. It took me years to find reason enough to give up my beloved 35mm SLR (single lens reflex) setup, and ultimately, that reason was travel. My travels to Thailand in December of 2004—just about three years ago now—coerced me into the world of pocket-sized digital cameras.

I had tried to take the plunge once before. It was back in March, 2002, and I'd purchased the freshly released, and much anticipated, Minolta DiMAGE X. The results were so lackluster that I promptly sold the camera on eBay, and actually made a small profit.

Shooting digital offers instant satisfaction and no development expenses—this I liked—but for a fellow like myself with an extensive SLR setup, it was still too much of a compromise in image quality. Soft images, ghosting artifacts, and purple-fringe vignetting were not something I was will to accept.

But in 2004, I was forced to make a choice between traveling to Thailand as a backpacker with film and an expensive SLR, and giving digital another shot. Ultimately, I had such a pleasant experience with the diminutive Canon PowerShot SD300, that I never returned to film.


I was busy in 2005 finishing off an MBA and shutting down my domestic life. Although I love photography, what I knew of digital photography was limited to my camera, and the little I bothered to read about the subject. So I suppose it's of little surprise that advances in this field went generally unnoticed then, and since.

One of the things that continue to frustrate me with these little point-and-shoot digital cameras is their ability to handle contrast. I often really miss the results that came from my (bulky) SLR, but know this is something that I have neither the funds nor desire to replace with a digital iteration.

Shooting with a pocket-sized digital camera, I'm often forced to meter light in specific parts of the scene and make detail sacrifices. Perhaps the sky is overexposed/blown out so that the cathedral or whatever is properly exposed, or the details in the shadows are lost for similar reasons. Oftentimes there's just too much breadth of color and light in a frame to capture with a limited digicam CCD sensor, compared to everything the eye sees, and the photo suffers because of it.

But just as digital cameras have been advancing, so too are the tools with which these images can be manipulated. This is where HDRI enters the scene.

HDRI—Who Knew?

The intent of high dynamic range imaging (HDRI) is to accurately represent the wide range of intensity levels found in scenes ranging from direct sunlight to shadows. HDRI was originally developed for use with purely computer-generated images, and later adapted to produce a high dynamic range image from a set of photographs taken with a range of exposures.

About a week ago I came across an HDR photograph by Trey Ratcliff, pulled off his Web site, Looking at it and several others, I said, "I want to know how he created images like these." Other examples of his work in HDR are here, here, here, here and here.

I read through Trey's tutorial on HDR on his Web site, learning about the process for the first time. It essentially consists of taking three to five images of the same scene at different exposure levels—from underexposed, to overexposed. Then images are combined using software to create a multiple-exposure HDR image. Details from the shadows are taken from the overexposed image, details from the highlights are taken from the underexposed image, and when combined with the compromised exposure (and jazzed up a little bit), yield some amazing results.

After learning about it, I had to try the technique myself, and took a few sample shots while I was out walking Simba, the Boza family's dog. My Nikon P5000 lacks the RAW (uncompressed) image mode that gives the compilation program all the great data it needs to do its job the best, but you can still use a series of regular JPEG images to create an HDR image.

I set the camera to take a trio of bracketed exposures at the greatest range possible (-1.0, 0, and +1.0). The series looked like this:

After merging these images together as an HDRI, a process called 'tone mapping' is then applied so that an image with this range of color can be displayed on a computer monitor, or outputted to a printer (all of which have a limited dynamic range that falls far short of the spectrum contained in the HDRI).

The results:

Pretty damn cool, huh? It's far too colorized in the test setting I toned it with (looking more like Miami's South Beach than Lima), but you get the idea.

Turning about 90-degrees to the left, I snapped another trio of cross at the dead end of a street a few meters from Tatiana's home. The photo is marginal, but typical of the type I might snap in a hurry on the street and upload to the gallery:

This is the post-production HDR image:

HDRI Weaknesses

Clearly, the images that can be produced using tone mapped HDR images are amazing. Trey Ratcliff's collection of stunners is testament to that. But there are some limitations for average travelers:

You really need a tripod. Although software can somewhat correct for the movement between exposures when combining the HDRI, it's not perfect. It takes a few seconds for me to let the P5000 fire off a trio of exposures, and each consecutive one really should be aligned just as the prior.

It is possible to create an HDRI from a single exposure, but it requires photos be taken in the RAW format, something that isn't possible on my camera, and isn't convenient for many travelers, who don't want to take photos stored as 12MB image files—the space requirements for those without a laptop are too great.

Yes, you really need a laptop. If you're planning to do image manipulation of any kind without a laptop in your pack, it's going to have to wait until you go home. Either you bring the equipment with you, or you wait until you have the time and tools necessary to do the job. Installing software on a machine in an Internet café isn't going to happen. And with you taking three to five images for every one that you'd normally be storing on a memory card, you're going to need a way of offloading and storing images other than CD or thumb-drive (possibly a portable hard drive if a laptop isn't practical).

This technique isn't for the average drunk-snapshot-in-the-bar type of photographer or image (as HDR images are only useful when there's a lot of contrast in the frame). It takes knowing a thing or two about image manipulation and light metering, but the software couldn't get any simpler for this stuff. Adobe Photoshop CS2 and CS3 both have an HDRI merge feature, but after playing around with it I find the process to be cumbersome and the results to be generally unimpressive. Trey Ratcliff produces his images using PhotoMatix, by HDRsoft, with Photoshop for retouching.

Happy snapping.



December 15th, 2007

Awesome! I never even considered this! I'm spending New Year's Eve in Dublin and about 10 days in that gorgeous country plus a handful of days in Amsterdam before going back to careerism.

I need to go pick up a couple memory cards (they're so cheap now anyway) but whether I take my old beat up Canon or my pricey-too-chicken-to-travel with Canon SLR, both have RAW ability. I'm traveling with an Asus eee PC, I wonder if TheGimp has any HDRI manipulation capability. I need to play with this now!


December 20th, 2007

You might want to look into the Joby Gorillapod. I've seen it at backpacking stores like REI. It's a lightweight, flexible tripod, perfect for your kind of travel.


Craig |

December 20th, 2007

You know what, I'd already found that bad boy on Think Geek and planned on picking one up next time I pass through the U.S. — great suggestion!


December 28th, 2007

Hi Craig,

I discovered Stuck in Customs about the same time you did, with a similar impression. I read the same tutorial, and wanted to try it immediately. I am impressed that you followed up and are already experimenting with the technique, while I have yet to take another photo. You are inspiring me.


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