One of the keys to great photography is knowing when to hit the shutter button, but sometimes that's easier said than done. Triggertrap Mobile is an iOS app which aims to help you capture that elusive shot by turning your iPhone or iPad (2 or new) into a smart camera trigger capable of making your camera take a photo at exactly the right moment.

A follow-up to the Triggertrap V1 we saw last year, the app requires a dongle and cable to connect your iOS5 device to a DSLR (more than 270 cameras are supported thanks to a range of connection cables) and enables you to take photos using 12 different triggering modes, many of which are activated by sensors in your iPhone or iPad. If you don't want to control an external camera, the app can also be used to trigger the internal camera.

Highlights include two never-before-seen ways of triggering a camera (at least in a consumer device), Distance-Lapse and Eased Timelapse. Distance-Lapse uses the GPS capability of your iPhone or iPad to take photos at regular distance intervals, this means resulting movies look like the entire journey was conducted at exactly the same speed. Eased Timelapse sees your camera triggered at intervals according to mathematical formulas to give the appearance of time speeding up or slowing down.

The app also includes regular trigger modes such as Cable Release (think standard wired remote control) with Bulb (holding the button for long exposures), Timed Bulb (press to start and finish), and Long Exposure options (where exposures can be set anywhere from one second to 60 minutes). Other modes - many of which rely on sensors in your iOS device - include standard Time-Lapse, Sound Sensor, Shock & Vibration Sensor, Metal & Magnetism Sensor, Facial Recognition, Motion Detection, Star Trail, HDR Timelapse and HDR.

While makers of Triggertrap Mobile suggest sticking to manual focus, the app can also activate auto-focus before telling the shutter to fire. This is done using a multi-channel system which allows users to set the timings of each channel and also means the app can be used to fire an external flash along with the shutter.

The Triggertrap Mobile app is available in the iTunes App Store for US$9.99 and the dongle and camera connection cables are available from the Triggertrap website. Expect the dongle to set you back $9.99 on its own, or $19.95 with a cable. An Android version of the app is said to be in the works.

Source: Triggertrap

Here's a quick vid from TriggerTrap highlighting the unit's features.