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Old 25-05-2019, 07:30 AM
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Paul Haese
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Paul Haese is offline
 
Join Date: Jan 2009
Location: Adelaide
Posts: 9,937
Hi Stefan, I have had three QSI's from about 2009 onward. I have found the table daunting too but I believe this problem is caused from the idea that the filters are within the casing of the camera and not in an external filter wheel.

So for example my GPU corrector is 55mm back focus. The Camera has a back focus with the mount I have of 50.17mm. If I subtract 1mm from 50.17 I end up with 49.17 and that subtracted away from the 55mm back focus is 5.83. This corresponds really well with the actual imaging for curvature.

Or looking at it another way, you add 1mm to the 55mm back focus of the corrector and then subtract the 50.17 from the 55 and you get a sum of 5.83. ie 55+1-50.17=5.83 (apply BODMAS). In this example you need to add the filter to the back focus of the corrector for refraction and then subtract the actual back focus of the camera.

Hope that helps.
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