A robotic carton unloader is configured for automatic unloading of cartons from a carton pile. In various embodiments, the robotic carton unloader may include a mobile body, a movable robotic arm attached to the mobile body and comprising an end effector, a conveyor system having a front portion, and a lift attached to the mobile body and the front portion of the conveyor system to move the front portion. In some embodiments, the conveyor system may comprise a front-end shelf conveyor configured to be moved (e.g., raised, lowered, laterally moved, tilted, etc.) relative to the body of the unloader. The front-end shelf conveyor may be moved separately for positioning below the robotic arm in order to receive cartons from a small distance. The front-end shelf conveyor may be moved via various mechanisms (e.g., scissor lifts, pedestal lifts, etc.).