Production is the stage when filming happens and footage is recorded. The goal of production is to capture all the required shots, although some short "pick-up" shots may be filmed during post-production.
"We'll fix it in post."
No you won't. Whether the problem is lighting, sound, acting, the perspective of shots, film speed, there is no such thing as "fixing it in post." Get it right the first time.
Filming will be a lot easier if you have spend time and thought on the planning process.