Back focus issue when transporting on rolling stand
Posted 18 March 2015 - 10:23 AM
Posted 18 March 2015 - 04:34 PM
Posted 18 March 2015 - 05:06 PM
Posted 18 March 2015 - 05:39 PM
What lens and adapter are you using? I haven't had any issues with vibrations and back focus either.
Posted 18 March 2015 - 06:33 PM
Posted 18 March 2015 - 07:28 PM
Posted 19 March 2015 - 11:38 AM
ah, yes that would be the logical thing to do. but I am on a show that is against all logic. I assumed there are no real issues rolling the camera on a stand with pneumatic wheels. The back focus issue in the past season probably wasn't a result of rolling the carts, but the carts had to take the blame.
Posted 22 March 2015 - 04:33 PM
Here's a possible answer.
I use a Beefy Baby Stand. I also got some studio wheels, and they are not specifically made for my stand. All well and good. But sometimes, depending on the spread of the legs when the stand has been opened and wheels locked into place, the wheels vibrate VERY violently as the rig is rolled along. Upon examination, I see that the wheel caster is not quite vertical and as the wheels are turning, they are not able to roll and adjust as the stand is moved along with a perfectly smooth rotation. Hence the vibration. Of course, it must be all three wheels since they are all locked onto the legs of my stand.
One game wheel might not be an issue, but three wheels vibrating rapidly is something I can easily feel- and I'm only moving my docking stand 30 feet or less.
Perhaps the objectionable problems last season were the result of this kind of asymmetrical force on the wheels creating rapid vibrations. See if one of the A.C.'s was on last year and remembers this artifact. They would have been pushing the rig daily, they'd remember if the wheels turned very smoothly or were problematic.
Oh, and I use the hard wheels. 8" pneumatic? Hell, even if they are not seated well, I'd be thinking that the vibrations would be minimized by the air in the tires. But as a global possible solution, check to see how the wheels are in terms of smooth operation.
Best to all,
Peter Abraham, S.O.C.