There are four apps out there that I have found so far that offer video pre-recording: Precorder (three versions), Camera Awesome, Mogo Video, and PastVid. They each offer different features, so see my reviews under each one separately if youre interested in precording.
Precording is a technique where the app immediately begins capturing video when it is launched. It fills up a buffer, either user set or set by the app (typically 3-5 seconds) with video footage. When youre recording something and youre not sure when the "highlight event" is going to happen, this pre-recording really helps. Simply point your camera and wait. The moment the event begins, tap the record button.
Now, normally you would lose the first second or two, but with pre-recording, the recording actually starts BEFORE you tap the button. This way you dont lose anything.
Unlike some of the other precorder apps, precording is really what this app is all about. The three versions only differ in the amount of time the video is buffered, and for most uses, three seconds is plenty, so start with the free version to get familiar with the concept.
Precorder continues to buffer your video no matter which way your camera is turned, landscape or portrait. If you decide to change the orientation at the last moment, you can, but the recording, once you tap the button, will be locked in to that perspective. Precorded information from the other perspective will appear sideways in your final saved version. This is unlike the other precorders that simply dump the buffer and start buffering all over again when you turn the iPhone. As long as you have a way of editing your clips, it really doesnt matter.
I upgraded to the 10 second buffer version, but even at that, I usually keep the precording set at five seconds. Three would be fine, but its a little tight.
None of the precorder apps offer zoom yet, so I make that request of this developer as well: Please, add video zoom!
Thanks for a fun little app. Looking forward to updates.