Strobes

[Noitarud]

Idea was to view motion stationary (it may even allow improved photography! Not sure about external flash app).
This can be with the torch, yes, and you may consider the LCD, but I have noticed other applications adjust the backlight rather fast (no fade) so can use that too (faster? Give it a try, and even if you don't distribute it, tell us how fast they all flashed their lights!). allow duty adjustment too!
As for relevance to PP, there is otherwise none.

[Noitarud]

I notice backlight action is too slow, consider screen.
As for interface, widthways swipe is adjust timing, short axis double swipe offset, single is duty. perhaps adjust colour white on, blue off (may help reduce dazzle effect).

[Noitarud]

…consider screen image instead. I did research on LCD module refresh rates, 85Hz may be the absolute Max, but the manufacturers wouldn't bother so expect 60hz. Pixel bluring would hinder blink contrast at fast speed.

[Noitarud]

I had used a strobe app in the past, the screen was difficult to look at for adjusting it. Make it so the light is dimmed and/or black brighter when (until a timeout) there is a finger on the screen but not on a control (control can be adjusted by relative motion!).

Maybe can be set to respond to sound 😎