Does it record the full frequency (20-20,000Hz), or a smaller range? Can this be changed when developing a camera app?
What is the frequency range that the iPhone camera records videos in?
Are you talking about audio? By default, AVFoundation captures movies at 44.1 kHz. The native (harware) sample rate on recent iOS hardware is 48 kHz.
If you are asking about audio, remember the iphone is a consumer-level device/mic, and those types of products generally support 20~20Hz, which should allow your app to ballpark - expect low frequencies to be de-emphasized. Can't be changed as long as you rely on the built-in mic, I assume.