The Samsung Galaxy S4 embraced users with lots of wonderful features, among which the camera is an often used one. But, for users who like to take photos or snap videos with Galaxy S4 camera, there's a problem that no way of unlocking the phone could guide users straightly into the camera app. Without a shortcut of camera on Galaxy S4 lock screen, users have to do more clicks to get into the camera app. Like many of the S4's advanced features, this is optional, and disabled by default. It is quite easy to enable it. The following three different kinds of camera shortcuts could help you put on the Galaxy S4's lock screen.
Method 1: from the Settings app, go to My device > Lock screen and enable "Shortcuts." From there you can customize which shortcut icons are shown down below on the lock screen, and loading one of these apps up is a simple as dragging it upwards. Naturally, one of the defaults is the camera app.
The second and third ways both involve lock screen widgets, and you'll need to enable them through “Settings > My device > Lock screen > Multiple widgets”. Once that's done, you can go to Lock screen widgets > Favorite apps or Camera, which controls the widget that appears on the far right. The "camera" option is straightforward enough -- select it, and you get a big blocky camera shortcut, like on the Nexus 4. "Favorite apps" is a bit more versatile, and this allows you to customize a grid of apps -- one of these, of course, can be the camera app.
Still not quite understand the steps? Watch the below video to get how to add shortcut of camera app on your Galaxy S 4.