Haven't you ever thought that It would be fun to take a picture at the same place with the same camera position and angle just as done before, but is it possible?

With Onion Skin Camera, it's possible.  You can take a new picture, seeing one of your old pictures translucently superimposed in the finder.

For example, the Onion Skin Camera is good for taking pictures of;
- construction process of a building.
- the same face before and after make-up for comparison.
- your kids' growth records year by year.
- seasonal changes in views seen through the same window.
etcetera, etcetera.
You can utilize the Onion Skin Camera anyway you like.

There are other known time lapse camera Apps for iPhone such as "iMotion HD," "Stop Motion Recorder" and "TimeLapse."  Problem is, with those Apps, you are forced to fix your camera position, or can not quit the Apps till you finish the whole project.

With the Onion Skin Camera, you can start your project whenever an idea occurs to you and you can halt the project, then restart any time.
You can utilize any readily taken iPhone's standard format pictures you want as onion skins, or translucently superimposed images, which allow you to set a desired composition.
Good thing also is that pictures taken with the Onion Skin Camera can be saved as in the standard iPhone photo format in the Photo Album.

How about creating a slide-show in iMovie by utilizing the Onion Skin Camera pictures you have taken?

Have fun!