I have a xperia ray mobile phone. I wanted to get one of those spy camera applications so as to film undetected. I tried a couple. Best so far were ninja cam and hidden mobile camera IMO. All have a problem, when I turn out the camera there is a bip(regardless if the sound is off or on). Is there any app that doesn't have this problem? Or any other way I can delete that sound, I don't really need it anyway. Thank you.