Complex sentence: While working up the ladder and joining the International Cinematographers Guild as a camera assistant, Yellen had the opportunity to shoot second unit footage under Eric Steelberg on "Quinceañera", which won the Grand Jury Prize and the Audience Award at the 2006 Sundance Film Festival.
Split into simpler sentences: While working up the ladder and having joined the International Cinematographers Guild as a camera assistant, Yellen had the opportunity to shoot second unit footage under Eric Steelberg on "Quinceañera". Quinceañera won the Grand Jury Prize and the Audience Award at the 2006 Sundance Film Festival.