Im using a schneider 120mm HM macro on a Cambo Ultima 35 + canon 5d, but im having difficulties to get to 1:1 as i dont have a long bellows (and cambo never produced one for Ultima 35) and i need the full 30cm rail to get to the maximum closeup (ie. I can focus on a watch with most of the wetistband... i cant get closer like cropping on the warch movement or smaller parts...)

so, im wondering if im doing anything wrong...

on a related note, I saw online that someone is using extension tubes attached to the Symmar 120 on a regular nikon 850
and they seem about 10-15cm...whereas i need to use my full 30cm rail to achieve the maximum macro
any thoguhts?