Hi Jai,
My findings....
Both of our iPhone 5 units do this on 2G (GPRS) only, if 3G or WiFi is used our cameras are 100% perfect!
We recently went on a two week holiday to Corfu (from UK), thinking that the holiday photos will be a nightmare to take, but guess what, Corfu had little or no 2G but a brilliant strong 3G signal (Cosmote) and we managed to take 100's of photos and tons of video with not one single glitch on any phone! PERFECT!
There is nothing wrong with our cameras themselves, it is a 2G signal problem effecting the use of the cameras.
Your location and signal type & quality is the important factor here.
Reading earlier posts, I was also hoping that upgrading to iOS7 would fix it once back at home.
Well after testing on iOS7, the issue has been improved here but not completely gone.
So far it seems better not worse so upgrading was a positive move me.
I have only seen the intereference when the camera App is minimised on the multitasking screen (double tap of home button) but not using the actual camera app itself yet, it is early days though!
At the moment my work around for this is to use Airplane Mode when I am in poor signal areas.
This is now even easier to do in iOS7 from Control Centre.
Kevin.