> However, unlike Google Glass, modern smartphones play a "camera shutter" sound to at least give some indication that they are capturing an image to the people

> However, unlike Google Glass, modern smartphones play a "camera shutter" sound to at least give some indication that they are capturing an image to the people around you. I just tried with my modern smartphone: it's completely silent, both on photo and on video mode. The default might have been to play some sound, but I probably toggled the option off when I first got it, because I find these fake shutter sounds (unlike the real mechanical shutter sounds from DSLRs) to be annoying. No, the real difference is the positioning. To take a photo or record a video with a smartphone, you have to hold it in a particular position (back or front pointing directly at the subject), which isn't usually the normal "relaxed" position to hold a smartphone, and this gives people around some indication that you're capturing an image. With Google Glass and similar, the normal position is the ideal one to record video.