Re: Preston Fiz3 not matching marks
Hey Saul,toggle quoted messageShow quoted text
The pre-marked rings for the Preston FIZ HU3 are mathematically created, whereas the majority cinematic lenses are hand made and even the focus markings on 2 identical Cookes s4 50mm will differ, especially at the Close Focus end. The Preston Handunit is mathematically calculating the distance between set points to then predetermine where the focus points should be (mathematically) but this isn’t always the case.
Other factors - The gears on the motors - Are they the correct gearing? Are they clean? Yes, These do need to be cleaned & yes it makes a difference
When doing a standard calibration, and turning off the focus ring so you can use blank rings, do you get a difference each time you calibrate?