I use a app called "silent cam switch" . It allows you to use the stock camera app and it automatically switches your phone to silent when you activate the camera. The only issue I have is most of the time after you close the camera app it's supposed to turn your volume back to where you had it, but it never does so I have to manually turn my volume back up.
Posted from my Beast Galaxy Note 5
DEVICE HISTORY (since they got smart)
PHONES: Galaxy Nexus, LG viper, Galaxy s3, HTC Evo 4g, Galaxy Note 2, Galaxy s5, LG G-Flex, Galaxy Mega 6.3, Galaxy s6 edge, Galaxy Note 5. TABLETS: Galaxy Note 10.1 gt-n8013, Galaxy tab 3 7.0. WATCH: Galaxy gear