The idea is to have a fixed box, but have frames move at the same time such that space between them expands. Then camera(s) on a stick could move into the expanded area and take a photo

Pros:

• Box is sealed, so no need to let the warmth in
• You can observe 8 frames at the same time if you have 7 cameras from both sides, as one camera observes 2 sides. You can’t see 2 sides at both ends though
• Potentially cheapest mechanism

Cons:

• Need long box as all frames expand at the same time.. so potentially 3x the normal size to have enough focal length
• Camera must be moved, unlikely that it can have enough focal area