If you’re an owner of a Sony Xperia Play, you might have thought that using the R button makes sense when using the camera. However this is not an option on the stock camera.
Luckily, XDA forum member Zoop57 has thought about this and modified the app to enable the R button as the shutter button for taking photos and recording videos. not only that but the XDA member has also enable the L button to act as focus in photo mode.
There does appear to be a current bug where the shutter button on the screen remains highlighted until you tap the screen but the XDA member has started that this may be resolved in future.
The mod has been bundled up into an application, which is available for free on the Market. For further information including a link to the app, head on over to the modification thread._________