A low mass on a 'spring' has a high resonant frequency - a high resonant frequcy oscillation loos terrible on film.
Add some jello of a cheap rs camera and you have a challenging combination.
As vehicles move up and down you need a 'boom range' to cover that. Typically that distance is not 'small' so the device commpensating for it cannot be 'small'
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A depressing reply which represents many dissapointments for me over a decade but hopefully builds a scepisism in you which may mean you dont throw your money away on non proven items.
Id probably be looking at a ronin S on (and this is where it gets hard) a device, maybe a cloud mount but possibly a 3 axis arm.