A gentle nudge, the smallest spark, often leads to a grand embark. At the summit of a journey's start, I'm the edge, the crest, the finest part.

I shoot but I don't kill, What I capture is moving still, I often stand between lights and action!

I place with care, Harden with time, Begin the scene, Disappear at dusk. What word am I?

I stand without feet and block without hands. I hear every secret but never reply. I separate friends, yet hold buildings together. What am I?

They have not flesh, nor feathers, nor scales, nor bone. Yet they have fingers and thumbs of their own. What are they?