This app was mentioned in 2 comments, with an average of 2.00 upvotes
I bought the full version of this camera app and quite liked it, but the developer tried to release a 2.0 update as a new app that would require repurchase. User reaction to this strategy was strongly negative, so the developer backed down, and offered the update as an opt-in beta, then quietly disappeared. The app has not been updated at all since late 2014.
ProCapture.
I've been using it since my Nexus 4 days so I usually download it to phones just to see how it does. It does great on the S6. Try it out, the touch the screen to focus and take a pic feature is great and I feel it gives a better focused pic than the stock camera app.
https://play.google.com/store/apps/details?id=com.neaststudios.procapture&hl=en