Calibrating follow focus systems for repeatable lens markings across multiple lenses

Gear

ZephyrCan I fly my Alexa or RED on a Zephyr?389

Master SeriesIs a used Master Series rig worth buying as a first big rig?191

BFDHow do I power my BFD receiver from my camera or sled?186

VoltCan I retrofit a Volt onto my existing sled or gimbal?168

ArtemisHow do I power my camera and accessories from an Artemis sled?166

MDRWhere can I mount my Preston MDR on my rig?143

ModulusIs there a Modulus option for HD wireless video?141

G-70Will my G-70 fit my vest, gimbal or sled?126

FI+ZCan I control iris and zoom wirelessly, not just focus?60

HU3Where can I get my HU3 repaired, refurbished or repainted?60

CineLiveHow do I pack and case my CineLive rig for transport?54

G-70XHow does the G-70X compare to Pro Titan, Xarm and other arms?46

Trinity 2Is Trinity 2 SUP 3.0 firmware safe to install or buggy?46

Ultra VestWhich vest should I choose for my body size, comfort and operator type?39

2005Follow Focus forum

21 years old. Gear and prices may have changed since.

DisputedParticipants disagreed and reached no conclusion. Read the findings as positions, not as an answer.

Calibration should be performed consistently from the infinity mark to the closest focus mark rather than to the physical end stops of the lens barrel
The lens should be positioned at approximately the middle of its range of travel when initially engaging the motor to distribute resolution evenly
Marking the lens position used during calibration on the marking strip allows for repeatable calibration when swapping between the same set of lenses
Consistency in every setup step is essential for achieving repeatable calibrations that can be marked semi-permanently for the duration of a job
When motor torque causes bar twist at end stops, calibrating only to infinity and close focus marks can provide more consistent results than attempting full barrel travel
Minor adjustments to a potentiometer can compensate for small drift between calibrations
Electronic upgrades to some follow focus systems can improve backlash characteristics and enhance marking repeatability

Different lens manufacturers require their own unique calibration markings due to varying mechanical designs
Backlash in older follow focus units without electronic upgrades may prevent reliable strip reuse
Motor torque interacting with mounting bars can introduce inconsistencies during calibration to hard end stops
Perfect tension reproduction matching an autocal remote focus system may not be achievable with manual calibration procedures