Do I REALLY need a counterweight?

Discussion in 'Movi Technical' started by Stephen Brown, Jun 28, 2019.

  1. Stephen Brown

    Stephen Brown New Member

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    Hey Folks...I've got a 7Plus (192g with case). I want to add a Momentum 58 Tele lens (70g). Is counterweight necessary? Is it possible to just move this heavy phone a bit more to the arm side? I understand that there's a limit to this adjustment-- the gimbal will eventually move into view, and the clearance between the phone end and the handle could get pretty tight. Has anyone tried this? Thanks, Stephen
     
  2. Kevin P Riley

    Kevin P Riley Member

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    Get the weight.
     
  3. Pavel Houda

    Pavel Houda Member

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    I don't have the 7+, but I have no problem using the Xs Max with the Moment 58mm over the wide lens by just shifting the phone in the clamp (no counterweights). The reason why they shift the phones so far out are for the wide and anamorphic lenses, that "see" the roll servo. Your setup would be even better in this respect than the phone alone.

    If they used the servo layout topology similar to the Snoppa Atom, where the roll servo is right on the back of the clamp, you wouldn't need any counterweights.
     
    #3 Pavel Houda, Jun 29, 2019
    Last edited: Jun 29, 2019
  4. Kevin P Riley

    Kevin P Riley Member

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    The counterweight counters the additional weight on the back of the phone as well, there is no moving the phone in the clamp to adjust for the weight on the front of the camera.
     
  5. Pavel Houda

    Pavel Houda Member

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    Theoretically yes, in practice, the "moment of inertia" is much smaller along the tilt axis than along the roll axis, so in this case, the balance there is not necessary and the servo can handle the load easily. Even FF suggests that to their customers. Majority gimbals only compensate with counterweights on the roll arm. Theoretically, you are correct.
     
  6. Kevin P Riley

    Kevin P Riley Member

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    I bought the counterweight and the Movi at the same time, so I’ve never tried it. My experience with only adjusting the roll axis on the osmo mobile 2 was not the same. Unless you began moving dead slow, the camera would flop forward.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Stevie, welcome to the forum.

    If it's not too much trouble, would you be kind enough to change your user name to your real first name and last name, please? The reasons for this (and how to do it) are explained here: http://forum.freeflysystems.com/index.php?threads/real-names.497/
    Thanks
    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  8. Pavel Houda

    Pavel Houda Member

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    The motors on the MCR are monsters in comparison with other mobile gimbals. According to their data sheets, the Osmo Mobile 2 or the Zhiyun 4 will not even support my iPhone XS Max with case and screen protector. Yet people are routinely loading them with lenses and counterweights, and often they see them going limb due to overload of the motors that don’t provide enough torque to deal with the load, specially if it isn’t balanced just right, or if the system experiences big jolt. The motors then require too much current and the gimbals shut down the motor drivers to protect them from destructive overheating.
    The MCR on the other hand doesn’t even specify payload weight (which by the way is smart, because it is the moment of inertia- like flywheel- that the motors have to oppose, not just plain mass), yet it can move my iPhone XS Max in Moment case, screen protector, Moment wide and filter adapter, 62mm to 77mm filter adapter, fixed and variable ND 77mm filter, counterweighted with around a pound of aluminum and stainless steel. It can still have all the torque necessary to counteract the inertia of all that, so it will not have any problem with the Moment Tele lens along the tilt axis.
     
    #8 Pavel Houda, Jun 29, 2019
    Last edited: Jun 29, 2019
  9. Stephen Brown

    Stephen Brown New Member

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    Thank you for all your responses. I'll let you know if there are any problems but it sure sounds like it'll work. By the way, I asked because I like the simplicity and convenience of phone cameras, love the extra performance of the MCR, and want to add a bit more sparkle with a tele. But, at a certain point, it feels like Rube Goldberg and easier to use other equipment.
     
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  10. Pavel Houda

    Pavel Houda Member

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    You are welcome. One of the benefits of the Moment tele adapter is that is in case of my Xs Max and placed over the wide lens, it can provide shallower bokeh than the native tele lens already on the iPhone, because the Wide has a lower f-stop. Like every other add-on, it is useful rarely, depending on shooting style, so most of the time you can put all the overhead into the backpack.
     
  11. Stephen Brown

    Stephen Brown New Member

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    As Pavel predicted, the Moment 58 works great without the counterweight contraption. Then I tried the wide angle Moment 18, which doesn't work without counterweight because the MCR unit is captured in the frame. So I jerry-rigged a simple counterweight by pushing a square channel strut washer through the Moment Wrist Strap. Pretty good performance, enough weight to slide the 7plus so the MCR is out of view, cost 30 cents, and 5 seconds to set up. Works great with Majestic and Orbit mode. Barrel Roll is compromised.
     

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  12. Pavel Houda

    Pavel Houda Member

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