I have Camera FV-5 ($3.95) It gives you good control over sensor settings similar to a Pro DSLR. ISO, shutter speed, bracketing, focus lock, timer/burst, etc.
Also Camera ZOOM FX Premium ($3.49) which is very similar to FV-5, but has lots of cool post effects you can add in.
I have a Galaxy S5 and they both do really nice, so I imagine the S8 will do even better.
A new one I am just starting to test is Lapse It Time Lapse Pro ($2.99) For videos, time lapse of course, you can adjust input settings, filter modes, interval time, macro, etc. Just starting with it, so I can't give full feedback yet. ;-)
AMAZING! i had no idea these existed, I appreciate you telling me about them! I'll try it out and let you know how it goes!!
You're welcome, happy to help. 😊 You get very creative with your pics/vids already, but hopefully they will give you some extra options.