I think I need to take a break from this. I have just confused myself with various distances.
The 55 mm back focus cannot be achieved with the WO 44 mm T mount adaptor as it is 38 mm thick. A normal imaging train is:
18 mm (sensor flange) + 38 mm deep (44 mm T mount) = 56 mm with the Flat 61A doing a "minus 1 mm adjustment" from 12.9 to 11.7 for a Sony. A magical number of 67.7 mm is needed for the Flat 61A.
With the OAG, 18 + 38 + 16.5 (OAG width) we have 72.5 mm which is longer than anything the Flat 61A can do. I have to lose 4.8 mm. The old 28 mm deep T Mount would do it for me but they seem to have moved to another planet. Does anyone have one they don't need?
