Standard Helix (Magnesium) with Encoder upgrade. Camera was C300 Mark II, with 16-35mm 2.8L III. I've balanced and shot on Ronin and Movi in the past with no issues. This was a really bad experience. Again, I'm not trying to smack talk Letus, I think I just got a bad unit or something.
C300: C300 Mark II on a gimbal
- Thread starter slavikb
- Start date
Standard Helix (Magnesium) with Encoder upgrade. Camera was C300 Mark II, with 16-35mm 2.8L III. I've balanced and shot on Ronin and Movi in the past with no issues. This was a really bad experience. Again, I'm not trying to smack talk Letus, I think I just got a bad unit or something.
control4userguy
Well-known member
^Top-shelf equipment like the Mg Helix w/encoders (first attempt for Letus) should not act like this. "Bad unit"? I wonder about that. The whole idea behind feedback from encoders is to roll that info into the PID algorithm. PID tuning is an art form and some users get lucky and plug-in numbers that get close to yielding smooth op. "Noisey" motors are easy to diagnose as well as controllers. I've read here about the "exceptional" service Letus provides. I've also read about crappy service (REDUser) from off-shore vendors operating small offices here in CA. So, I gotta ask, did you return the unit due to your circumstances or Letus' inability to accurately diagnose or replace the unit?
I bought the unit directly from Letus and called them the moment I opened the box because some screws had fallen out and there were no instructions at all. After briefly talking to them about assembly, I watched the videos on balanceing, got it perfectly balanced (which they verified by Skype later) and turned it on. It proceeded to have a large rhythmic "wobble." I read up on it and saw which settings should address that sort of low frequency movement, but decided to call them back and have them walk me through it since this was a $3800 package.
Initial PID adjustments got rid of the low frequency movements but now it was vibrating violently at higher frequencies. I continued to work with them on it until the end of that day, sending videos of the vibrations, then having them diagnose the problem, and recording a new video. At the end of the day it wasn't fixed.
I called back the next morning and we proceeded to spend the ENTIRE day troubleshooting the issue, and no resolution was reached. Since the company who sold it and made it couldn't get it to work, I returned it.
control4userguy
Well-known member
^Thank you your time and explanation. I understand your situation.
Amira-user
Active member
bonjourno videoshot, i see on your instagram you have a 'chrosziel magnum' FF attached to your camera, can you share your thoughts and your likes/dislikes about it 
Update: I finally had some time to sit down and work through the PID settings at every angle, and looks like turning on the low-pass filters is what was needed. Still needs some finessing, but that's the ticket, at least for these heavy C100/C300 cams.
Hey guys, as described above there seems to be some inherent issues with the encoded motors of the Helix Jr and Standard. I didn't have time to finesse the PID settings when doing the initial review, so I assumed any shake/jitters were from my incorrect PID/Power settings. But I finally had time to spend a few hours with the encoded Junior today, and it seems to continue to have issues, no matter the PID settings. It's not noticeable when shooting, but when reviewing the footage it's clearly jittery, even after the camera has been balanced well. Maybe lighter cameras don't suffer from the same issues, since the C100 is a heavy/tall camera for the Junior?
At any rate, I've emailed Letus to see if there's something we're not doing right. In the meantime, the original non-encoded motors are still great and I stand by them. I hope we get a resolution soon. Lately I've been shooting with the encoded Helix Standard with a C300II but at 60p, slowed down to a 24p timeline, so none of the jitters have been evident. Thanks to others on here for pointing out the problems, this forum continues to be a huge resource.
Cheers,
Slavik
Hey guys, as described above there seems to be some inherent issues with the encoded motors of the Helix Jr and Standard. I didn't have time to finesse the PID settings when doing the initial review, so I assumed any shake/jitters were from my incorrect PID/Power settings. But I finally had time to spend a few hours with the encoded Junior today, and it seems to continue to have issues, no matter the PID settings. It's not noticeable when shooting, but when reviewing the footage it's clearly jittery, even after the camera has been balanced well. Maybe lighter cameras don't suffer from the same issues, since the C100 is a heavy/tall camera for the Junior?
At any rate, I've emailed Letus to see if there's something we're not doing right. In the meantime, the original non-encoded motors are still great and I stand by them. I hope we get a resolution soon. Lately I've been shooting with the encoded Helix Standard with a C300II but at 60p, slowed down to a 24p timeline, so none of the jitters have been evident. Thanks to others on here for pointing out the problems, this forum continues to be a huge resource.
Cheers,
Slavik
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Hi Amira-user,sorry to disappoint you but that is the Came-Tv FF. I've ordered the new FF Atlas from Redrock on december and still waiting for it and last time i heard from supplier he talked about shipping after NAB announcement! 
rogar-Shock(DBG):and that's why I bought the came tv FF and it's an affordable FF and have to say that i'm surprised how good it works! not bad at all for the price...
. I've ordered the new FF Atlas from Redrock on december and still waiting for it and last time i heard from supplier he talked about shipping after NAB announcement! rogar-Shock(DBG):and that's why I bought the came tv FF and it's an affordable FF and have to say that i'm surprised how good it works! not bad at all for the price...Ok so after looking into it and talking with Letus, it basically it still comes down to PID settings, there's nothing inherently bad with these motors. Sorry for jumping at conclusions. The new motors are just not working with the old PID settings, so you have to start from scratch, and the defaults are not working for the Canon Cinema cameras. Anyway, I'm working through the PID settings and will hopefully have it back up and running with some recommended settings to other folks here.
control4userguy
Well-known member
As I said earlier, hardware defects are relatively easy to detect when watching the feedback graphs. Letus would have seen this. If the hardware is functioning AND the match between motor capability, payload weight and payload balance is proper, then it routinely boils-down to PID tuning. Letus can't be on-site to fix problems (unless you send your gear to them) but they could have "dialed in" to the desktop of user's computer to do a little tuning. BTW, I have 30 years experience with PID logic...
Michael Thames
Carbonite Member
Hi Pure Drifting, oh sorry for such a late reply, I didn't see this until today. To be honest I really haven't used the Helix jr much. I had it set up pretty good with the C100 MKI, but after screwing around with the PID settings on the MKII I might had altered the known universe and caused an irreversible chain reaction that I can't recover from. I think part of the problem was I took off the control handle to used with Slavik's set up, but when the Zacuto extension didn't work I tried to go back to the original position and can't quite locate where that is.
However, if you are going to use it with the C100 mki I think it works good without any PID adjustments. As long as you aren't stressing it out doing too much quick jerking moves, it seems to work fine. For me learning that a minimal amount of movement is the key. At first it thought cool, I can do all kinds of movements but found that looked bad. I'm sure you professionals know more about that than I do.
On another note...... I'm in Bangkok Thailand right now. I took my 5D3 and C100 MKII with me, just to shoot some stuff for a little video. I was walking around holding the C100 and some guy said, is that a C100? Turns out his name is Steve Miller with highdefsound.com. We it it off and became friends. Small world. Maybe some of you might know him.
puredrifting
Major Contributor
Thanks for the update. Fingers crossed. It seems as if you can get the Letus Jr. setup and balanced correctly, it can be a very handy tool but you can also screw up the settings as well, I wish the interface and PID as all much more automated, Letus has a slide show written by their PID expert on their website that says you can never use the automatic button in the software like my Zhiyun Crane. Most of us don't want to become PID engineers, we just want to buy a product and shoot with it and have it work every time. Slavik has been working on settings for the new version with the encoded motors, it's looking encouraging, I think once he gets it dialed in with the C100, the encoded version will be amazing.
I've heard of Steve Miller, small world. Enjoy Thailand, it's definitely on my bucket list.
I've heard of Steve Miller, small world. Enjoy Thailand, it's definitely on my bucket list.
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We got a Letus Jr. here, too. Haven't played with it too much, but my initial reactions seem to line up Michael's. C100\I seems pretty ok on the Jr. if balanced well. The C100\II seems a bit more shaky. I haven't touched the PID settings at all yet.
Here's a short video I made while testing the C100\II for the first time on the Jr.
I had the Zacuto zgrip relocator attached as the right handle, and the 17-55mm 2.8 IS set to somewhere 17 and 24mm. IS was on naturally. Sorry about the sound--I didn't mute it: https://vimeo.com/user21442843/review/207520726/2414340939
Here's a short video I made while testing the C100\II for the first time on the Jr.
I had the Zacuto zgrip relocator attached as the right handle, and the 17-55mm 2.8 IS set to somewhere 17 and 24mm. IS was on naturally. Sorry about the sound--I didn't mute it: https://vimeo.com/user21442843/review/207520726/2414340939
Do you have any footage that isn't slow motion?
I'm impressed - didn't realize there was such a thing as logic with PID! Can you recommend a resource for learning more about PID/Power/Filters and gimbal motors? I thought I had an ok grasp on PID and power, but having to get into low pass filters now I'm a fish out of water. Thanks!
puredrifting
Major Contributor
Thanks for sharing this!
Michael Thames
Carbonite Member
As Drummondb says for some reason the MKI behaves better than the MKII. But, really you don't need the hand grip set up to make the MKII work, as most everything you can do on the LCD.
The reason I got the MKII was primarily for the on board mic, so I could use it on the Helix and match up the scratch audio with an external recorder. When I attached a mic to the MKI since it was a coiled wire it pulled the
Camera too much, but I'm sure if you spend some time fussing with it you can get it right.
Been having dinner every night with Steve great guy. Yes, you must visit Thailand some day.
puredrifting
Major Contributor
I'm going to be working a pro sound mixer all of the time I am shooting with the Helix Jr. All I need is audio. Doesn't have to be good audio, just scratch for syncing. 1.8 oz right on the the handle cold shoe. https://www.bhphotovideo.com/c/prod...101_video_dslr_camera_mounted_microphone.html
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Michael Thames
Carbonite Member
People have been searching low and highfor a mic like this for the C100. Good find! Maybe I'll get one and use the Letus with the MKI since it responds better.
puredrifting
Major Contributor
Credit where credit is due, Slavik found this mic and told me about it. It's probably pretty junky and sounds terrible but if it's just for scratch, seems perfect.