This is part of one of my rigs. Utilising a standard model aircraft Tx and Rx unit. The Canon A640 like many Point & Shoot cameras also has a video out socket. This allows me to provide a video downlink to the small monitor. It's not ideal as sometimes in bright sunlight the image is very near washed out completely. I might in the future go for one of the video glasses that are starting to emerge on the market, once they reach a reasonable price! To stay legal the video downlink is on 2.4Ghz. The main part of the rig is a standard production Brooxes rig.
At the end of 2006 the UK Authorities relaxed the power output limitation for the 2.4Ghz Spectrum equipment model aircraft have started using . This puts such equipment into the serious RC bracket and not just the 'park flyer'. With that in mind I'm replacing the above rig to a Futaba 6EX giving me the flexibility to utilise it for model helicopters if I decide to go down that route.
Its not clear from the photo of the rig but I usually leave the lens adapter/extension tube on the camera while flying. It helps protect the retractable lens of the camera from unexpected forced landing damage.
Depending on the camera you choose, there are many ways of releasing the shutter. Some keep it very simple an do what is know as AutoKAP. Again this can be simple or as complicated as you wish. From randon shutter release using an intervalometer to timed positions, rotation and camera pitch.
You can just see the CHDK information on the video link screen, bottom left.
There have been reports elsewhere from RC Model Flyers concerning loss of command using the 2.4Ghz type system while using 2.4Ghz video systems.
I am now using the Futaba 6EX along with a 2.4Ghz video system (unbranded). I have encountered no problems so far. To ensure there is no frequency clash do not co-locate the Video Tx aerial and the Servo Rx aerial too close together and try to oppose their orientation. Another tip is to ensure you use the upper frequency range for the Video Tx. The RC 2.4Ghz Rx sytem tends to favour the lower end of the frequency spectrum so I've been informed. All you are trying to achive is divergence in as many parameters as possible.
New developments are coming out all the time. I now have a DuneCam System which is basically a bespoke package that will allow many and varied scripts to control the rig & camera, both directly and or in combination with CHDK. Scott Armitage whose brain child the system is also has developed gyro controlled servos. When used on the various axis they can smooth out rig movement.
Another system is that of Linnar's called CamRemote. This is the aerial element of the rig only and uses a conventional R/C to action it. At the camera end it can utilise either the USB port or IR facility if the camera has it. It can also be used as a stand alone intervolmeter too.
James Gentles also supplies various gadgets that will allow cameras or camcorders to be controlled remotely via R/C or indeed automatically. His site is a good first port of call to see what is on offer if you are just starting out.