No worries. As I should have guessed, there's an app for that. In fact, a quick check of the App Store reveals there are several apps, all designed to endow the 3GS with HDR photography goodness.
Pro HDR is my favorite so far. For a mere $1.99, it delivers simple high-dynamic-range tools for novices and experts alike.
In case you're not familiar with it, HDR photography combines an under-exposed photo with an over-exposed one, culling the best elements of each to produce a final, third photo.
Like iOS 4.1's new tool, Pro HDR snaps two shots in rapid succession. However, Pro HDR gives you the option of using Automatic or Manual mode: the former handles the exposure settings for you while the latter lets you set it by first tapping a bright area of the preview image and then tapping a dark area. (My take: Automatic works just fine; you'll rarely need to mess with Manual.)
Not every photo will benefit from this kind of software wizardry. But in my tests, some photos looked a little better while others improved dramatically.
As they say, pictures speak louder than words. Check out these two photos of a newly remodeled kitchen--the first taken with the iPhone's standard Camera app, the second with Pro HDR.
The Pro HDR shot exhibits much better balance; the Camera app couldn't handle all the light pouring in from the two windows. And that's where HDR--and, indeed, Pro HDR--shines: it fixes exposure problems that would otherwise ruin a photo.
The catch, of course, is that you need to hold your iPhone rock-steady while the app snaps its two shots, meaning it's better suited to scenery than to people, who are always blinking, moving, and so on. But even if you move a little, or your subject does, the app does a good job aligning and merging the photo pair.
Once it's done processing the corrected image, you can make adjustments using brightness, contrast, saturation, warmth, and tint sliders. However, the app lacks a "reset" or "defaults" button that removes any unwanted changes.
Pro HDR lets you save and e-mail your finished photos at full resolution. While it would be nice if it had Facebook integration, it's far from a deal-breaker.
In fact, I'd say that for $1.99, Pro HDR is a must-have app for both
iPhone 3GS and iPhone 4 users, as it gives the latter a lot more control than Apple's software. (Speaking of which, according to Gizmodo, that HDR update might just become available on jailbroken iPhone 3GS and 3G models.)
If you've tried any other HDR apps, hit the comments and let me know how they fared.