Weight shift during focus with zoom lenses on Steadicam rigs

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2011General Discussion forum

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

Some zoom lenses exhibit internal element movement during focusing that can cause pitch and roll instability on a Steadicam rig, particularly when focusing from middle distance to close range.
Angenieux compact zoom lenses are designed with Steadicam compatibility as a priority.
A heavier rig with faster drop time can reduce the visible effects of lens element weight shift.
Testing a lens on a stand by operating the focus remotely allows direct observation of any impact on rig stability.

The original observation involved an older Panavision lens model from that era, which used older focusing technology.
The phenomenon may vary significantly between individual rigs and operators based on balance setup and technique.
No quantitative measurement of the effect was provided in the discussion.