The increasingly sophisticated cameras built into Nokia phones – consider the Nokia N8, with a pro-quality 12-megapixel sensor – call out for increasingly sophisticated photographic software, and HDR Photo Camera is exactly that. It’s an app that exploits the N8’s high-end camera to produce often-striking images.

The Qt-based HDR Photo Camera app is a serious piece of photographic technology, and it’s priced accordingly. It sells for $9.99 on Ovi Store. But we can see the software appealing to anyone who is serious about making photos with their N8.

The name HDR stands for high dynamic range, which refers to a technique that can overcome an innate limitation found in virtually all cameras. No matter if they use film or a digital image sensor, most cameras are limited in their ability to record extremely dark and extremely bright areas in the same photograph. Thus, when shooting a sunlit scene, you can capture either details within the darkest shadows or details in the brightest areas, but not both.

A large collection of HDR photos, some of them quite stunning, can be seen at the Web site of something called Smashing Magazine. And there are more, and a complete tutorial in HDR, at a site called Stuck in Customs. These images show how the HDR technique can make cloudy skies look almost surreal in their texture while also showing the details of darker objects on the ground, for instance. HDR shots frequently show up in advertising, precisely because they are so eye-catching. And with digital cameras – or, now, a Nokia N8 smartphone – applying the HDR method is much easier; with film, a fair amount of darkroom manipulation was required.

A slightly more technical explanation of HDR: Suppose the scale of brightness in that sunlit scene ranges across a scale of 15 tonal steps, from 0 in the total black of a deep shadow to 15 in the total white of a woman’s white dress in the full sunlight. A camera’s light-capturing ability, however, might extend across only 10 steps, which means that it can capture only one extreme or the other, but not both at the same time.

The HDR technique manages to cover the full breadth of this wider range of tonal values by merging several images, each made at a different exposure. In the case of this app, three exposures – light, medium, and dark – are made of the subject and these are then “fused” together, a process that can take as much as 1 minute. This means, of course, that this app is not the one to use for shooting your pals at a party or making snaps of your child playing soccer or football. HDR essentially works only with static subjects such as landscapes, buildings, and street scenes.

If you look around the Web, you’ll find lots of examples of HDR photography. Many of the images are quite spectacular, with impossibly bright colors and remarkable tonal ranges. From what we could tell, HDR Photo Camera doesn’t reach the extreme heights of what’s possible in HDR photography, but it does a superb job considering it’s running on a smartphone, not a powerful desktop computer working on images shot with a professional camera rig.

Here, for example, is a shot we made with the app (that’s our foot in the foreground):

And here are the three separate exposures that the software fused to make this HDR photo. The first one captures some detail in the TV screen at the far left while the next two let that screen go completely black and reveal more detail in what’s visible through the window at far right.

More examples of photos made with this HDR software on an N8 can be seen at the Web site of the developer, Intellsys, a Brasov, Romania-based company. As you’ll see, the app can produce images that look slightly otherwordly, with skies that are unnaturally dark and color palettes that are too soft and grayish. Contrast can easily be lost, making the images look a bit dull. Such results just show that HDR is not magic, and it is certainly not be the best way to shoot every photo.

Moreover, obtaining the optimum results may require some adjusting of exposures and other parameters. And HDR Photo Camera offers a fair number knobs to twiddle, so to speak, if that’s your thing. Its Settings menu lets you adjust exposure times, image quality, and three advanced settings: contrast, saturation, and “exposedness.” We admit, we did not try out all of these to see what effect they have on final images, but the app’s Help screen, available by tapping on the icon showing two gears, is fairly informative, as are Intellsys’ support pages on the Web.

Some things to think about: Because this app shoots three photos and, in effect, merges them into one, it’s critical that the camera is not moved during the initial shooting. Alas, the N8 does not have a tripod mount, but we found that holding the camera as still as possible –  or even better, bracing our elbows against our legs, while sitting, or against a wall or table – produced good photos nonetheless.  In a night-shooting situation, though, hand-held HDR photography might be a challenge. (Perhaps, it occurs to us, one could strap the camera’s flat body to a standard tripod with a good-sized rubber band.)

Here, for fun, is another HDR image we shot with our N8:

Granted, it’s not the most exciting photo ever made, but notice that the sky shows some late-in-the-day color and that there is lots of detail in the parking areas to the right. Now, check out the normal, undoctored photo that the N8 makes of this same scene, which lacks those details:

In this case, we might actually choose the “straight” photo as the one that captures the light of the moment most accurately. But chances are, with some tweaking of the HDR app’s controls, we’d be able to produce an even better HDR image than the one we show here, which we made in a jiffy using the app’s normal settings.

Be aware that this app does soak up CPU cycles in your phone, and memory, too. To keep it from choking the N8, Intellsys limits the size of photos it can handle – but only a little. The firm also recommends shutting down other apps in the phone while engaging in HDR processing. And it offers the option of handing off the three preliminary images for fusing on a desktop PC, with more processing oomph. This requires a pieces of software that the company has said it will make available in early 2011 – any minute now, in other words. This approach strikes us a good idea for handling the CPU-intensive image-fusing process, although it does mean you can’t see the results until you get home from shooting out there in the big bad world.

There you have it, HDR Photo Camera, a piece of software that will keep your N8 seriously busy but also producing some striking images that are not possible otherwise. If you’ve got any interest in photography, this is definitely an app you’ll want to try out. (In the name of completeness, we must note that another app recently reviewed in this blog – Harald Meyer’s Camera Pro for N8 – also includes HDR functionality in its broad menu of features.)

HDR Photo Camera is available in Ovi Store for $9.99 (USD).