Thalia Lapse HD/R is an unwieldy name, but it's an app that does something that has been a bit of a holy grail for iPhone photographers. The app takes time-lapse sequences, but that's not the unique part. This US$2.99 app takes multiple exposures and tone maps them to give you a high-quality finished HDR movie with much better dynamic range than you would get taking single shots.
The app also includes de-ghosting, so if there is any variation within the multiple shots, like blowing vegetation, it will be automatically eliminated. The app outputs in Apple Quicktime format at 1080p resolution, and you can add music from your iTunes library.
In addition, the app lets you adjust the saturation, for striking colors or something more subdued. You can take your movie at resolutions other than 1080p, including VGA and 720p. You can also select how many seconds each frame will occupy in playback. The app uses the sensors in the iPhone to let you know if the phone is level, which is a great idea.
A tripod or some type of steady platform is needed for this app to be effective. You're not going to be able to handhold your camera and get any worthwhile results. For my tests, I used a Joby GorillaPod stand, which was perfect for this kind of work. It's also important to have plenty of battery or be hooked up to a power source, because hours of photography will keep the screen on and that is a battery eater.
Thalia Lapse HD/R is a really terrific app with some unique features. The HDR capabilities are the standout feature, and the app works as advertised. To have all this capability in a smartphone is a wonder, and if you've wanted to explore HDR time-lapse photography, you no longer have any reasons not to try it. Check out this online video to get an example of how the app works.
Thalia Lapse HD/R requires iOS 6 and is optimized for the iPhone 5. It is a universal app, but I think it's best suited for the iPhone 5's high-resolution camera.