It’s no longer a case of saying “One, Two, Three, Smile” then taking the photo. Smile Shutter App make iPhone camera can automatically trip the shutter at just your subjects smile. It could be useful when shooting unpredictable subjects, such as a bunch of children at a party.
For it to work best, the subjects eyes shouldnt be covered with bangs of hair or many types of sunglasses. And eyes should be as level in relation to the camera as possible.
Detection distance: 0.3M - 2.0M
Response time: 0.2s - 0.5s depend on iPhone Camera Focus time
Immediately saved to the Camera Roll