Is there a specific kind of USB-C cable that needs to be used for the Lidar unit? We have made a custom matte-box mount for the Lidar unit to attach to because the matte-box interrupts the field of view of the lidar from the front. However, on most of our lenses, the lidar cable length is preventing us from being able to mount it on the top of the matte-box. We've tried high-data rate cables, really expensive USB-C thunderbolt 4 cables, basic USB-C cables, and even the Tilta extended monitor cable just in case.
Every cable we try doesn't work.

The bigger question for me is surely the LiDAR sensor's design and positioning in relation to the camera sensor has been carefully determined in order to perform its role accurately. Moving it to a matte box seems to me like it might as well not be there. I could easily be wrong as my family will attest but DJI unsurprisingly make a big deal about the LiDAR sensor's position on its rail, which suggests you'd have to be very diligent or very lucky if you got it to be anywhere close to as precise if mounted elsewhere.

TooDeep Posted at 9-17 01:55
The bigger question for me is surely the LiDAR sensor's design and positioning in relation to the camera sensor has been carefully determined in order to perform its role accurately. Moving it to a matte box seems to me like it might as well not be there. I could easily be wrong as my family will attest but DJI unsurprisingly make a big deal about the LiDAR sensor's position on its rail, which suggests you'd have to be very diligent or very lucky if you got it to be anywhere close to as precise if mounted elsewhere.

That was our original thought but we ended up testing calibration from both positions. What resulted is two calibration profiles for each lens with a "MB" or "Reg" -- so when it's in the default position it's loading the calibration data for the lens with the Lidar in the default position and the "MB" version of the same lens's calibration for the Lidar in the forward Matte-box position.

Works great, but only if the lens is short enough (at the moment) for the USB-C cable to reach the Lidar mounted in the forward position.

COLORGRADE Posted at 9-17 10:41
That was our original thought but we ended up testing calibration from both positions. What resulted is two calibration profiles for each lens with a "MB" or "Reg" -- so when it's in the default position it's loading the calibration data for the lens with the Lidar in the default position and the "MB" version of the same lens's calibration for the Lidar in the forward Matte-box position.

Works great, but only if the lens is short enough (at the moment) for the USB-C cable to reach the Lidar mounted in the forward position.

I'm not convinced. The distances you're moving it aren't long enough, if you're using the original USB cable.

I'd like to hear DJI's take on this.

Ford4D Posted at 9-17 12:16
I'm not convinced. The distances you're moving it aren't long enough, if you're using the original USB cable.

I'd like to hear DJI's take on this.

How could you possibly know what distances we're moving it?

COLORGRADE Posted at 9-17 12:18
How could you possibly know what distances we're moving it?

Easy! Because you said in your original post that none of the cables you used work EXCEPT the one that comes with the Ronin 4D's LIDAR unit.

Therefore, you couldn't have moved it far enough to know definitively.

It may be able to compensate within a mounting range roughly equivalent to the cable length, for example.

Ford4D Posted at 9-19 13:48
Easy! Because you said in your original post that none of the cables you used work EXCEPT the one that comes with the Ronin 4D's LIDAR unit.

Therefore, you couldn't have moved it far enough to know definitively.

Ford, it's not a matter of the distance (far enough or not) that dictates if or not the cables other than the original DJI cable work with the system.

We have tried every other kind of USB-C cable we can, and yes, the cables we tried were long enough for us to attach both ends and mount it to our custom matte-box mount. The issue is that even with a long enough cable, the cable itself doesn't allow the Lidar unit to communicate with the camera once plugged in. I'm trying to find out from DJI or another user who has successfully found a third-party cable that allows the Lidar unit to still function.

To be clear, we're not talking about the distance. We're talking about the fact that any other cable other than the original, regardless of the distance, does not allow the Lidar unit to function. It just doesn't work, no matter what kind of third party USB-C cable and no matter its respective length.

I would love too a longer cable for the Lidar unit.

+1

COLORGRADE Posted at 9-20 06:12
Ford, it's not a matter of the distance (far enough or not) that dictates if or not the cables other than the original DJI cable work with the system.

We have tried every other kind of USB-C cable we can, and yes, the cables we tried were long enough for us to attach both ends and mount it to our custom matte-box mount. The issue is that even with a long enough cable, the cable itself doesn't allow the Lidar unit to communicate with the camera once plugged in. I'm trying to find out from DJI or another user who has successfully found a third-party cable that allows the Lidar unit to still function.

And with all due respect, I think you're forgetting what I was specifically replying to. You said that the LiDAR works no matter where you mount it.

And I'm saying that I'm not entirely convinced that's true. I have a strong feeling that if you somehow COULD mount the LIDAR farther, it would begin to throw off the auto focus. And the shortness of the cable is why you're not experience significant problems yet.

If you're careful, you could theoretically mount it somewhere where it's essentially equidistant to most focus points. But the longer the cable and the further away from the lens, the more you're introducing the possibility that the distance between the LIDAR and the focus point becomes significantly different from the distance between the focus point and the lens.

It's just simple geometry. ( / optics.)

Now To Solve Your Problem:

Everything we know so far is that DJI likes to sometimes use unique USB-C to USB-C cords that are essentially proprietary. They usually use standard connectors but have unique (or uncommon) wiring configurations. For example, this cord had a similar reputation for being proprietary and irreplaceable with 3rd party cords:

https://store.dji.com/product/ro ... ontrol-cable-type-c
https://www.bhphotovideo.com/c/p ... type_c_control.html
https://www.amazon.com/DJI-Ronin ... ype-C/dp/B07VDMYB5L

When one was opened up, it was discovered that it had 6 wire cores, instead of the traditional 4 that most USB-C cords use.

So while I can't guarantee this particular DJI cable will be exactly the same as the one used on the LIDAR, there's a possibility that it will still work.

(Of course, there's always the possibility that somehow the data-rates involved in the connection between the LIDAR and the camera body need such low latency that they cease to function reliably over longer distances, and the software is keyed in to detect longer lengths. Who knows!)

I'll say this though: If you aren't willing to try it, let me know and I will certainly bite the bullet to find out. All in the interest of sharing this knowledge with the rest of our community!

Good luck!
Hope you have a great rest of the week