Backfocus error tolerance ?

[Nikolas74]

So i am planning to put together my camera , rotator , filter drawer and in my qualqulations i will be -0.45 or -0.55mm of the required 55mm spacing..

Is that error going to give me problems in my images ? 

[Waldemar]

The required spacing is not always the right one. The only way to get the right spacing is by trial and error with an adjustable spacer like this one:
Baader VariLock 29, lockable T-2 ExtensionTube 20-29mm with spanner tool (T-2 part #25Y) (baader-planetarium.com) a 29-46 mm spacer is available too.
This will show you which way to adjust: FF distance to sensor.docx
Of course if your spacing is too large because of your rotator and filter system, you may have to find thinner gear or settle with a not perfect distance.
Only way to find out is to try... 

[Nikolas74]

Many thanks... Its good that I have one in my drawer 👍