Welcome Inspire Pilots!
Join our free DJI Inspire community today!
Sign up

X5S Balancing Question Lumix 14-42

Joined
Jan 17, 2019
Messages
237
Reaction score
63
Age
83
This may draw the search engine admonition, but still needs an explanation rather than what I cannot find. I shoot primarily prime lenses on my X5S but thought I'd tinker with the Panasonic LUMIX 14-42 with its zoom capability. Not necessarily a great lens but can come in handy at times.
I have it perfectly balanced with lens fully retracted and the gimbal/I2 not grumbling when zoom tube extended, but doesn't the 'moment arm' length affect the fulcrum, balance point, and is it something I should be concerned about. Or, since no gimbal warning just presume all is ok? Or is my Physics 101of yesteryear in error and it's balanced throughtout the range of the zoom, if balanced while retracted?
 
This may draw the search engine admonition, but still needs an explanation rather than what I cannot find. I shoot primarily prime lenses on my X5S but thought I'd tinker with the Panasonic LUMIX 14-42 with its zoom capability. Not necessarily a great lens but can come in handy at times.
I have it perfectly balanced with lens fully retracted and the gimbal/I2 not grumbling when zoom tube extended, but doesn't the 'moment arm' length affect the fulcrum, balance point, and is it something I should be concerned about. Or, since no gimbal warning just presume all is ok? Or is my Physics 101of yesteryear in error and it's balanced throughtout the range of the zoom, if balanced while retracted?
I prefer the word philippic (much harsher :p).

Does the bottom of the table in post #13 in this thread cover your concerns.
Its how DJI advise to balance the 14-42mm by using both ring A&B

 
No, it does not. The question as I wrote it seemed clear, but again: I am not using the DJI solution/balancing rings, I have the lens balanced; when extended does balance point change, and should that be addressed as there's no gimbal overload warning, or, is the imbalance within tolerance? BTW, I've only tested this on the ground without extensive 'working' of the lens. Perhaps during a normal flight the gimbal overload might occur, which of course would mean retracting the lens. Philippic is an excellent word, insulting enough but likely to pass most people's muster as its meaning not obvious.
 
  • Like
Reactions: The Editor
No, it does not. The question as I wrote it seemed clear, but again: I am not using the DJI solution/balancing rings, I have the lens balanced; when extended does balance point change, and should that be addressed as there's no gimbal overload warning, or, is the imbalance within tolerance? BTW, I've only tested this on the ground without extensive 'working' of the lens. Perhaps during a normal flight the gimbal overload might occur, which of course would mean retracting the lens. Philippic is an excellent word, insulting enough but likely to pass most people's muster as its meaning not obvious.
OK - you are correct in your assumption that as the lens extends its balance point will change (not much can be done about that).
Once airborne there will be much higher forces required by the gimbal motors due to wind resistance and inertial influences.
However, some people have, (in an effort to put as little stress as possible on the gimbal motors) come up with ways of turning off the aircraft so as to leave the lens extended and balancing in that position. It usually involves pulling the battery.

You could:

1. Use the DJI rings A & B which is the preferred way
2. Attempt the battery yank method and balance from there to minimize motor strain if using a Heath Robinson balance approach.

I hope that is a suitable rejoinder? ?
 
  • Like
Reactions: Mixchief
A superb answer as now I know how to extend the lens and balance fully extended, but as I reflect perhaps set midpoint and balance at that point. Truth is not an impressive lens but hoping it is at least as good the Z3 which can get some decent telephoto footage in a pinch.
 
  • Like
Reactions: The Editor
No, it does not. The question as I wrote it seemed clear, but again: I am not using the DJI solution/balancing rings, I have the lens balanced; when extended does balance point change,

The term you're searching for is COG or Center of Gravity. The COG MAY change, but it may NOT, depending on lens mechanics.

When you extend and retract a zoom lens, to us simple cave people, it simply looks like the only mechanical movement is the front lens moving in and out. Naturally, this lens movement follows the movement of the lens body - moving forward and backward. Naturally and intuitively, this would appear to change the COG. But this may not be the case. Most zoom lenses have multiple lenses and a complex gearing system that pulls one lens out AWAY from the camera body while simultaneously pushing the other lens IN toward the camera body. This essentially causes a "counter-weight" action inside the lens. Obviously - depending on lens weight and movement - this "counter-action" may actually allow the gimbal's COG to remain static or nearly static. Therefore, the zoom action doesn't put as much stress on the gimbal as one might think. That said...

What is counter-intuitive is that this mechanical "push/pull" action of the lenses may occur multiple times between widest and tightest settings. So the COG may move forward at say 30mm, but then may return to its original position @ 42mm.

A simple test would be to power down the gimbal and change the zoom a few millimeters at a time and take notes what happens to the balance of the gimbal. Now that you know what to expect and how the lens works, you won't freak out when the gimbal appears to lose balance @ 42mm, but regains it @ 35mm, but then loses it again @ 30mm, etc. You can take notes as to which zoom settings net the best balance for your gimbal and use just those settings.

You can bet DJI engineers took full advantage of this counter-weight zoom lens action in their Z3 and Z30 lenses.

Good luck.

D
 
Last edited:
Great reply, and I did/do know the term/abbreviation for Center of Gravity, not sure why I didn't use it. Regardless, you reply happened to catch my attention relative to an older point and shoot camera I had, as the T-W range was not a staight in-out, but kind of a double in-out. Difficult to describe, but you explanation hit home with me.
Thanks
 
  • Like
Reactions: Donnie Frank
Great reply, and I did/do know the term/abbreviation for Center of Gravity, not sure why I didn't use it. Regardless, you reply happened to catch my attention relative to an older point and shoot camera I had, as the T-W range was not a staight in-out, but kind of a double in-out. Difficult to describe, but you explanation hit home with me.
Thanks

Keep us in the loop. I'm curious to know how the balance of your gimbal changes relative to your zoom lens' FOV.

D
 
OK - you are correct in your assumption that as the lens extends its balance point will change (not much can be done about that).
Once airborne there will be much higher forces required by the gimbal motors due to wind resistance and inertial influences.
However, some people have, (in an effort to put as little stress as possible on the gimbal motors) come up with ways of turning off the aircraft so as to leave the lens extended and balancing in that position. It usually involves pulling the battery.

You could:

1. Use the DJI rings A & B which is the preferred way
2. Attempt the battery yank method and balance from there to minimize motor strain if using a Heath Robinson balance approach.

I hope that is a suitable rejoinder? ?
I thought I had answered this post, but maybe it was in another forum, and yes if you pull the battery there will be no power for the retraction to occur and it will allow you to balance it, try and set the zoom midway just in case the balance gets thrown off. I have trouble with my zoom, gets jumpy at times, that's why it is more of a stills lens rather than video.
 

Members online

No members online now.

Forum statistics

Threads
22,277
Messages
210,655
Members
34,334
Latest member
unitedconveyormktg