A good way to visualize the steps a slider can make is to visualize it with ticks like so:
What would be a good way to visualize a slider can only be set into certain steps without the use of ticks?
I got 2 sliders, both with a range of 0 - 300. The upper one can only be set in steps of 30 seconds (11 steps). The lower one doesn't have this restriction and can be set on anything between 0 and 300 (301 steps).