Camera With Internal Filter Wheel - Moravian Instruments G2 Series Mark II User Manual

Stated back focal distance already calculates with glass permanently
placed in the optical path (e.g. optical window covering the CCD cold
chamber).
When the adjustable adapter base, intended for camera with Internal
Filter Wheel, is mounted on camera without filter wheel, the resulting
back focal distance is only 21 mm.

Camera with Internal Filter Wheel

Figure 9: G2 camera head front view dimensions
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