June 20, 2009
High Dynamic Range photography, it seems, is still considered a bit of a novelty. That’s a shame. The technique has uses far beyond creating surreal, painterly images for the Flickr HDR Pool. And if you’re a travel photographer, it has double appeal: It allows you to take photos on the road, in impossible lighting conditions, with absolutely no extra gear required. (Nope, not even a tripod!) The only catch? Tedious post-processing.
These days, Photoshop has support for merging multiple exposures. And there are a number of third party applications available for the same purpose. But that still requires a round trip out of your favorite photo management application, which, with my limited attention span, I find highly disruptive. Creating HDR images shouldn’t be any harder than doing regular RAW processing in Aperture. And now, thanks to the Photomatix HDR Tone Mapping Aperture plugin, it isn’t.
Here’s how it works: I found a gorgeous tomb in Buenos Aires’ venerable necropolis—the Cementerio de la Recoleta. Because the necropolis is arranged in a north-south direction, noon is a great time to take photos, with hard but symmetrical lighting. For this shot, I wanted the sun in the frame, hidden behind the cross on the roof. I also wanted the tombs in the background well lit to add depth, while properly exposing the main subject. As you can see below, the automatic exposure on my trusty old 20D was not quite up to the job.
To create an HDR image, I shot two more frames, overexposed and underexposed by two stops. A tripod helps at this point, to make sure the images are perfectly aligned. But I’m not a fan of lugging one around, so all three frames were taken handheld. A handy tip here is to use continuous drive, to grab all frames in quick succession and minimize the alignment errors between them.
Back in New Zealand, I selected all three images in Aperture and fired them up in the HDR plugin. If you haven’t used a tripod, the plugin will align the images. It also offers to reduce chromatic aberration, which can be handy in high contrast images like this one. I found that the plugin generally does a great job of the alignment, but not so much of the chromatic aberration. More on that below.
Next up, the actual tone mapping. If you are the impatient sort, the Photomatix default settings do a pretty good job of many scenes. But you can probably get a much better result by making some small adjustments. If there’s a lot of blue sky involved, for example, I like to dial down the “Saturation Highlights” a bit. This keeps the blues from getting too overpowering. For the tomb, I also reduced the “Microcontrast” and increased the “Micro-smoothing” to achieve more natural texture detail in the stonework. As always, experimentation is the best way to learn about the various settings: Crank the sliders up and down to their extreme values to see what effect each parameter may have on your image.
At this point, I was pretty happy with the result, so I clicked Save and let the plugin generate the blended image. However, taking the loupe to the end result, it was immediately obvious that I had to do something about color fringing. Even with chromatic aberration correction enabled, many of the high contrast edges had cyan and magenta halos. In this case, I was lucky: Because the tomb itself was almost gray, I could use the Color brick in Aperture to select first the cyan, then the magenta areas, and fully desaturate both. To finish off, I also added a small amount of saturation to the stonework, lightened up the shadows, and added a very subtle vignette.
That’s it! From raw footage to fully processed HDR image in less than two minutes—plus travel time to Argentina.
The Photomatix plugin does have a few glitches. In particular, resizing the user interface can wreak havoc with the controls, and even make some of them inaccessible. And I’d like much better control over the preview image, which is currently of limited use for making detailed adjustments. But this is more than made up for by seamless Aperture integration, easy-to-use tone mapping controls, and great results.
HDR photography may get a bad rap for being overly gimmicky. But it allows you to get usable shots in difficult lighting conditions, at very low cost and with a minimum of hassle. And perhaps with an Aperture plugin now available, more photographers will add this useful imaging technique to their bag of tricks.
The Photomatix Aperture plugin is available from HDRsoft for $79. There is also a Lightroom version available, as well as a standalone application. And if you’re not ready to pony up the cash just yet, you can download a fully functional trial version and take it for a spin.