PowerCam for iOS is sort of a grab bag of photo tools wrapped up into one free app. It takes stills and video, and offers a tremendous variety of features for the photo enthusiast.
The app includes a tilt-shift feature for miniature effects, color splash for having specific colors appear in a black-and-white image, plus cropping, rotation, collages and frames. There is much to explore, the app is easy to use and the results are good. You can even specify high or low resolution output.
One odd quirk is that the app applies filters in real time as you shoot, which seems like a strange time to do so. Once a filter has been applied, it can't be removed. I think most people would prefer to do that after the image is taken. Fortunately you can, but only after making a US$1.99 in-app purchase.
That purchase also gets you the ability to pause while shooting video, and a panorama mode. Almost all post processing effects are part of that purchase. The app description in iTunes is a bit misleading because it shows things like Panorama mode as a new feature without mentioning it's a paid feature.
In the past, I've said I dislike free apps that are mostly come-ons for paid upgrades. With PowerCam, it's not quite so bad, because the app does a lot in the free version that will appeal to many. But I think most people will want the paid features, so it's best to think of this as a $1.99 app.
Seen that way, PowerCam is a capable app that's easy to use. There is plenty of built-in help, and experimentation is encouraged. Tilt-shift worked well in my tests, and there were plenty of options for making collages. Better yet, both features are in the free version, along with color splash, but that only works on live images.
PowerCam requires iOS 4.2 and works on the iPod touch and the iPad, but the app is not universal. There is a separate PowerCam HD version for the iPad. Reader Phil Olin points out that the app icon is pretty much a dead ringer for the Sony Nex 5 camera, which you could file under "tribute" or "rip-off" depending on your attitude toward the app.