I have the Atik OAG/EFW2/383L+ kit. Can anyone tell me EXACTLY what the backfocus of this complete kit is?
If memory serves the published backfocus is:
OAG=24mm
EFW2=22mm
383L=17mm
That adds up to 63mm. However, when I calculate the actual backfocus by using accurate image scale etc, I get a figure of 58mm. 5mm doesn't sound like much but it can greatly affect the correct use of flatteners/reducers, so I'm trying to figure out the exact backfocus of this kit.