While designing a Mecha for my universe I stoped really quickly when I was thinking about the optics.
Its a "Gear", VOTMS, "Wanzer" sized Mecha 4-6m the pilot sits in a cramped position in the chest and uses a kind of VR optic. It is encased in armor and is isolated and sealed to the environment.
Clarification This Mecha is mainly designed to be dropped via air. Its main goal is the assistance of friendly infantry or to stop enemy advances when the line is breached. In the later option those ACFs (Armored Cavalry Frames) - have priority Close Air Support or Close Artillery Support to accomplish their mission.
Options for Sensors
The main optic is situated in a "head like" mount above the pilots head. In smaller Mechas the head of the pilot might even be inside. When the pilot moves his head the Mecha-Head follows. Similar to the TADS of a Apache.
Addition based on Answers The optic provide zoomed high resolution pictures - IR and a low resolution light amplification.
Three Chameleon styled "eyes" are situated in the torso (left, right, back) those are computer controlled and provide a 360° situational picture. that could be blended into the pilots VR environment.
the third device is a telescopic boom in the back, combined with a LIDAR system the boom is used when the ACF goes hull down for better cover.
Help me to analyze possible advantage and drawbacks of each system. Reminder currently each of those three systems work different - there is no real redundancy. A more specific question might be: Is the choice of optic depended from the mission of a ACF? Can a ACF configured for Urban Combat use the same optic devices in the same locations as a ACF configured for Anti Tank / Sniping?