Electronic level/horizon indicator

[Jerry Holway]

Ron- since the colors are software driven, I'm going to suggest a display option where only the central 4 are green, then one or two bars on each side are yellow, then the others are red. (This may aggravate DP's and director's thinking you are WAY off level when they see RED, so maybe there are more yellow pixels on each side...) Something to ponder.

 

Jerry

[Afton Grant]

Hi Jerry and everyone else,

 

I'm currently using one of the demo units on the film I'm operating on. Jerry, I'll write up a much more in depth document with my feedback when the shoot concludes, but since we're talking about this aspect of the display specifically, I thought I'd chime in about it.

 

Personally, I don't feel the need for any yellow LEDs at all. For me, it's either level or it isn't. If it isn't, I want an idea of how much it isn't and in what direction, but I feel yellow is too close of a color to green. Especially with the current form factor (mounted above the monitor) where your eyes are on the frame and the LEDs are in your peripheral, I want a VERY clear indication when I'm off level and how to correct it. I don't want to have to look directly at the lights to see if they're green or yellow.

 

So if you're going to suggest a display change, I'd love an option where the four bars in the center are green, and everything else is red.

 

...these thoughts would be for anyone making a digital level. Thanks!

[steve wagner]

Folks seem to misunderstand the LED bubble and the pixel smoothing concept. Imagine you videotaped a real spirit bubble moving left /right and then filtered & reduced that down to one video scan line. You would see a very smoothly moving 'blob' moving left / right. Even though LED pixels are coarse and quantized you see a very smooth indication of your current horizon. It's not that big of a deal, just a way to get a little more linear operator feedback from a simple LED display. I'm sure you monitor folks already do this for your on-screen horizon displays

[RonBaldwin]

what do monitor folks do for their on-screen displays?

[Jens Piotrowski SOC]

The Alexa Plus has a digital horizon with No smoothing...

[Victor Lazaro]

I am adding notes on my monitor list about digital levels, please feel free to add, correct anything in the list. https://docs.google.com/spreadsheet/ccc?key=0Aln7iPn_kB2sdHowWElqVk1HWlRkdjgxcjJKN01XRGc#gid=0

[Eric Fletcher S.O.C.]

Regardless, once the unit is zeroed with the zero button and at a constant temperature, the display doesn't move more than about 1 segment or +/- .035 degrees due to sensor noise induced drift.

 

Of course, the real joy of the device is in its acceleration compensation, i.e., how it works while you are moving around. For this – for how good this unit is, I think a little video is in order.

 

This is a prototype of the "low-grade" version. Production ones work a tad better!

 

Can you address the right drift seen in the video towards the end? That's a fairly large error.

[steve wagner]

Eric, Jerry is violently moving the sensor side to side, easily producing multiple G accelerations in each direction then a multiple G stop. Very unlikely conditions on a real rig. And it handles it quite nicely IMO recovering zero in a second or so. As you know we have to combine the best mix of the gyros and accelerometers in an artful compromise that best handles the conditions you're likely to encounter as an operator. This is clearly a corner case. I'd like to see how others handle it, please supply a video of your favorite unit in a similar test.

 

By the way at this setting the bubble itself is less than 1/3 degree wide. The fact you were able to see the small zero recovery after a violent move shows how sensitive and smooth the display is.

 

Steve Wagner

[Wolfgang Troescher]

i'm really interrested in this device. If there are positive reviews I´m going to buy one. I don't want to use an "analog" level any more...

[Jerry Holway]

The quick video I uploaded (in response to assertions of uselessness) had the device on my desk that was not perfectly level in all directions like a granite table, and pressing down, lifting slightly, or rotating the device all could have introduced a light (1/10th of a degree or so) error. I'll try to upload another video when I find a less deviant surface.

 

Regardless, the key thing here is the acceleration/deceleration compensation. These are extreme in the video and the unit responds beautifully.

[Chris Poynton]

The iPhone level seems impervious to accelleration and may be a useful add-on for someone?

 

The app "Clinometer" gives a bullseye level with 0.1 degree accuracy for flat surfaces and a rolling bar level with degrees when placed on its edge. There may be other level apps providing ultra simple bar levels.

 

[Victor Lazaro]

The iPhone level seems impervious to accelleration and may be a useful add-on for someone?

 

The app "Clinometer" gives a bullseye level with 0.1 degree accuracy for flat surfaces and a rolling bar level with degrees when placed on its edge. There may be other level apps providing ultra simple bar levels.

 

 

I tried Tiltometer. https://itunes.apple.com/us/app/tiltometer-off-road-gyro-clinometer/id425306235?mt=8

Which you can set the tilt warnings to whatever angle you want.

It's used for off road driving.

The issue is that you still have to look away from the screen.

[Jerry Holway]

Try shaking tiltometer... and the resolution isn't good enough for us.

 

All of the apps i've tried are either damped to average readings and/or are subject to acceleration issues. Some have .1 degree resolution, which is great for static applications, but not so god for Steadicam. But they are getting better and better.

 

The original electronic level on the Model III (1984??) also had amazing resolution, but had nothing to dampen or eliminate acceleration, so it was kinda tough to watch. It was actually a really good indicator of going off course when trying to go straight ahead - I leaned this little fact from Larry McConkey.

 

Jerry

[Chris Poynton]

How about a custom Steadicam level app?

 

All of the apps i've tried are either damped to average readings and/or are subject to acceleration issues.

 

Clinometer seems set apart from the bar level apps I've seen. Acceleration doesn't seem to affect it. Sliding at high speed across a table or shaking back and forward makes barely a hair's difference.

 

 

The issue is that you still have to look away from the screen.

 

How about if Clinometer was re-packaged to generate a bar level at the very top or bottom of the iPhone screen. Then butt the device up against the bottom edge of the monitor image. The sensitivity of the bar level could be tweaked mathematically for preferred responsiveness.

 

The extra real estate on the bottom portion of the iPhone could be used for other info such as a log of tilt errors during the shot, perhaps linking in with timecode, displaying video feed from another camera, countdown to wrap time, etc, etc.

 

Alternatively, a data signal from the iPhone level (discretely mounted elsewhere on the rig) could be fed by bluetooth or dongle to a data input on the monitor for a more conventional bar level embedded in the image. (I have no idea if any Steadicam monitors currently have non-video data inputs at all - maybe USB for software upgrades? - but perhaps firmware of the monitor can be tweaked to incorporate iPhone feed if that option exists).

 

If a "Steadicam Level App" is of any interest, we could put together a wishlist for the Clinometer developers (... or possibly for Per Holmes of Hollywood Camera Work who developed Shot Designer for pocket blocking and is was recently beta testing a new timecode app with working tilte Cam Synch that can synch up to 254 devices and optimise for post-production workflow).

[Victor Lazaro]

Try shaking tiltometer... and the resolution isn't good enough for us.

I tried shaking and sliding it on a table. It's gyro balanced (needs caging to set the gyro). As for resolution it's as good (or as bad) as my Marshall level. I would be definitely interested in a steadicam level app. With super big bars that you can read with your peripheral vision.