Tag Archives: camera

‘Reverse’ IBL

I watched ‘Beyond the Black Rainbow’ last weekend and put together this test video,

This weekend’s tests were all about getting brainstorming on ways to improve Cambot and doing a bit of shooting in the studio. The studio time definitely helped to see what is working on Cambot and where it can use some improvements. The goal of my shoot was to experiment with lights.

I’ve spent some time before working with traditional Image based lighting, where I basically used a reference image from a location to digitally light a 3D model.


The reference image is typically a panoramic image unwrapped from a photo of a chrome sphere. The chrome sphere reflects a full 180 degree image of the reflection and in doing so the reflected light which would be cast upon the object. Typically a gray sphere is photographed at the same time for comparison with the in-progress/finished model.


I want to begin the same way, background locations photographed with reference spheres, then I want to photograph practical scale models to place in them. Typically this is achieved by attempting to mimick the lighting conditions, i.e. “the sun was here so we place a key light here, with a fill light on this side and…”. Then through a process of ‘match-lighting’ a cinematographer/Director of photography can reproduce the location’s lighting.

Why ‘Reverse’?
Now I want to turn this all around. In theory by using these reference images it should be possible to recreate the environment lighting on demand when photographing a practical model or actor. All that would need to happen is for a directional light source to project onto the surface of the model with the same hue and intensity as the reference.

This definitely isn’t a new idea, Paul Debevec, developed this years ago through ICT with his lightstage, pictured above, which I’ve linked here rather than attempting to further summarize it;

My approach is through the use of DMX stage lighting. There are multi colored lights capable of mixing Red Blue and Green in real time. These are also programmable via DMX512 protocol, so they can be set up to run through pre-set lighting configurations.

My Stage
I’ve been using these slimpar 64 RGB LED lights from Chauvet. I’ve currently arranged five of these in a half ring around my stage all pointing inward.

I plan to eventually upgrade this to a more automatic solution. There are a lot of software packages designed for stage techs, in fact many concerts and night clubs use these systems. There is also computer soft/hardware solutions more designed for filmmakers and animators like this card for Kuper which fits in with a Kuper motion control system. Or the DDMX-S2 from Dragonframe, which allows stop-motion playback control for incremental programs. For now I’m controlling these via the Chauvet Obey-10 mixing board, which allows me to set sliders for each of the color channels of the lights independently.

What I’d really like is for it to be able to process a ref image or video and reproduce it automatically, or use a video clip and essentially ‘play it back’. It makes sense that through software I could take a reference image and sample the quadrant’s hue and value, and route that into a DMX controller, then those values could be used for control of the lights.

The Science
The theory sounds great, but first I have to figure out the physical lighting limitations of this rig and about LEDs in general. I’ve often been warned about color temperature in photography. The difference between Tungsten (3200K), Daylight (5700K), and Fluorescent (4000k). However in attempting to get a clear answer to the temperature of LEDs I went down a rabbit hole. It seems this all goes out the window the moment you start color mixing. It is completely variable, which means it could be anywhere. Added to this LEDs typically have a more limited spectrum, take a look at

these graphs;

LEDs are often assigned a CRI which as I understand it, is how well they can reproduce the sun’s light, and thus how balanced a color will appear when illuminated by it. The other thing I’ve discovered about LEDs is the pulse width of the lights themselves. They aren’t actually constantly on, the light blinks on and off at arate so fast we can’t detect it. For many lights this is slowed down for the dimming feature/effect. This pulse width modulation which our naked eye cannot detect, even at lower frequencies will be detected by the camera when set to a high shutter speed.

I found it really interesting in this test to see the way the light’s wavelengths interacted with the shutter speed of the camera. It seems there are ways to work around it, selecting a lower shutter speed for example, but I haven’t quite figured out the science for it. Looking over forums shooting around PWM seems to be an increasing problem, especially for venue/location photographers;
Shutterspeed and flickering hmis
PWM is not your friend
LED flicker on camera

Cambot BRAIN storming pt2

Continued from: http://isdrab.com/2012/03/02/cambot-and-motion-control/

I’ve been talking with Chris Hassell from Co-Optic productions/TaskForce3D about my ideas for home-made Motion Control Rigs so I felt like it was time to update my notes on the project.


To begin what are the goals of this project?

      Inexpensive (as much as I’d love to get a MrMoCo rig I just can’t)
      Wide range of movement
      Programmable; Move-shoot-move, Play-back and Real-time controls
      Self-contained Modular/lightweight/portable

I hesitate to put a number down because it’d be laughable and embarrassing, but suffice to say I have very little budget, so I’m looking for the best solution for the least cash.

ProAim $475
When you look for cheap video gear on ebay you’re sure to find Proaim. Its not all bad, it works until it doesn’t. They offer some motorized tilt/pan heads, realtime only control, so I’d need a remote operator, or I’d still need to buy/make a ‘brain’ for it.

So, it may be great for long crane shots, but for this project its just too expensive…

Wide range of movement
How many axes of motion?
Ideally six; Dolly (back/forward left/right), Pan, Tilt, Jib/Crane, Jib/rotate

Yes. I want it all. I need to try and keep myself in scope for this project. My current Cambot has 7 axes of motion and may be just a bit too complicated for a programmable version; Dolly forward, incremental forward, incremental track to side, crane up, jib rotate, pan, tilt

There seem to be a few schools of thought surrounding this, there are the hobby-type time lapse/video; pan/tilt units, pan/tilt slider, and then there are the ‘pro’ solutions which can drive more channels but frequently connect to a computer; Ditogear evolution, MrMoco, etc. These can become monster rigs, and definitely not as portable, but can be capable of any possible moment.
For example MrMoCo’s Animoko;

C-MOCO is a german developed motion control system based on an industrial robotics arm.

It features a record and playback model for repeated motions along 7 axis, as well as embedding camera tracking data into R3D files for use in 3D and compositing applications. This is exactly what I want, but the fact that there is no price on their website tells me ‘if you have to ask, you can’t afford it.’

It seems like the biggest limitation for this is the ‘brain’; how many channels can I simultaneously control?


Looking at “brains” to control a MoCo rig, so far these have looked like the best options;

Basic Motion Controller Bundle $480
This is a kit for converting a slider into a MOCo unit. It only controls a single axis and is primarily intended for time-lapse. Like many, its max speed is controlled be swapping motors into place, using the gearing of the motor to speed it up or slow it down.

They also offer the SMART controller. $706

This offers the same single axis, but also allows for more control, live mode, ramping of speed, stop-motion, limit switches, etc.

Timelapse Camera Slider Motion Controller $225

This is the brain behind many time lapse rigs, it controls a single-axis for slider movements and also can be made to hook up to a telescope head for pan/tilt movements

Sadly there was an update done to the model of telescope head typically used, but the best ones are available from this site

Kessler Crane
elektraDRIVE BUNDLE PACKAGE with ORACLE Controller $1,314.95 $1k(controller only)

This can control two axis, so either a slider or a P/T head. It appears to be set up for very complicated programming, ramping motions, real-time/timelapse/stop motion, all that you’d expect.

Ditogear evolution $976.47

Ditogear really has an exciting product here. With up to 6-axis control, bezier controls for the ramping and motions, wifi enabled. It runs on android devices, with an IOS version expected in 2013.

Ditogear has also been collaborating a lot with this next one…

Dragonframe software $295
IOTA controller $750

It seems there may be no option for live playback since this is a software solution primarily for stop-motion, but through their IOTA (2-axis) controller or with an arduino (up to 8-axis) you can interface with stepper motors for motion control. The interface seems really slick, with bezier ramping and many axis of potential control. Additionally, and this part is very cool to me, they have created an interface allowing for the control of DMX lighting, so that while being able to control your camera’s move you can also have animated/programmed lighting. (I’ll be writing another post about lighting later)

eMotimo TB3 $750

Programmable for video and stop-mo, and self contained, supports Pan and Tilt plus outputs to control a third axis. It is also firmware updatable with open source architecture and a community.

CineMoco $415/$825

Slick, transportable and self-contained, the CineMoco dolly/slider presents a good option for a single axis of motion. It is programmable for Video/timelapse/Stopmotion. However it is $425 for the Dolly, and does not appear to have a supported way to control/program additional axis of movement. I did a bit of research though, and it sounds like they plan to allow for daisy chaining, and the developer of it says it can support up to 32 axis

Ideally this is something that can be easily broken down and brought on set, or out to a location to shoot background plates.

CamBlock $10k
The best in the ‘modularity’ category, and something I’d love to model off of is CamBlock For their brain they use a pocketPC running custom software.

But at $10k for three axis movement its out of my league.

Open Moco
This group of makers/hackers using the arduino have come up with some great open-source solutions, and appear very helpful, and many solutions have come from here, including the MX2;

John Pilgrim
I’m sure there are a lot of people online doing similar home-made rigs, but John is one who’s designs have stood out to me;His design for a pan/tilt head using stepper motors and pre-assembled gearing is pretty inspiring

Phidgets motors

These motors are apparently very quiet and will fit in Dynamic perception’s mounts;

Gini Slider $350

This slider looks very good, especially for the price; Modular and expandable. I could definitely see hooking up a motor and belt to it very easily;


80/20 seems like a lot of fun. Its T-slot framing, basically there are a bunch of extruded aluminum parts made to interlock, and designed essentially like an ‘industrial erector set.’
Ebay store

Servo city
Pan/tilt $649.99

In addition to having a wide selection of stepper motors, DC motors and real-time controlers, servo city also offers a couple pan/tilt heads. They look very well made and sturdy, but the price is a bit high for something which would still need a ‘brain’.

For realtime and playback they even have self-contained servo driver/controllers;

I’d hoped gathering these notes would provide me with a clear winner, but I’m still deep in the brainstorming phase. I’m tempted to start with the Gini slider to go with my current rig and piece together a modular arrangement, then work on finding a way to motorize it with Phigets and ServoCity motors, or one of the more expensive kits from ditogear or Kessler ($629).

But deep down I realize the brain should be the starting point. The best brain sounds like it’d be an arduino-based custom one, since the majority of the open source ones appear to be that way, and there looks like some good firmware starting points at Open Moco but not being an engineer or skilled programmer I’m hesitant to try and do that part my self. As far as prefabricated, the best ones seem to be the dito gear evolution with its nearly $1000 price tag, the more affordable Cine Moco, which would be great and self contained, but most useful if I can confirm that it’ll support more than one axis of motion, or the eMotimo with it’s three axes and integrated pan/tilt, but I’m a little discouraged by the the non-nodal pan and need to separate the camera from the current rig.

Continued here; http://isdrab.com/2013/04/13/cambot_pt3/

CamBot and Motion Control pt1

CamBot is the code name for my home-brew Moco camera mover. This is a project I’ve been working out for awhile on my own and its been through a few prototypes now, but I’m always looking for more inspiration and ways to improve it.

I’m beginning by using ways that use geared mechanisms to lock the camera, these are able to be moved incrementally creating repeatable camera moves through stop motion. Currently it is I’ve got CamBot set up with dolly track, a machinist’s table, rotary table, jib arm and geared tripod head. It works fairly well, and gives me a huge range of movement, but is tedious and time-consuming to operate.

Uploaded - 12\289-72

The next step will be to automate it. In theory this should be as simple as integrating stepper motors and an arduino. I always find myself wishing I had an engineer and machinist working for me, perhaps some day when I have a budget. There are a number of parts I’ve had to make myself, and lacking a proper milling machine they are wood, so in the future it might be worthwhile to call in favors or try something like this; http://www.emachineshop.com/

I’ll get there, its just been a slow process. It wasn’t *that* long ago that cambot looked like this;

The first Prototype was built from a broken artist’s easel and hardware, using a nut on a threaded rod to move the crane.


Other people’s Home-brew rigs

The same sort of rig has been done pretty well with motorized slider rails and telescope mounts for time lapse, which I hear are capable of doing real-time as well, but it gets into the $600-1000 range.

My friend Gus, has done some pretty awesome shooting with his;

Canon T2i
Canon 10-22 f3.5-4.5
MX2 Dolly Engine
Dynamic Perception Mini (3′)
Celestron Skywatcher
Kessler All-Terrain Outrigger Feet

“I’ve been using the MX2 and the Dynamic Perception Dolly for a while now. The big rig is a 6′ rail… I put together this mini-version of it. The MX2 controls everything, the slider, the telescope head, and the camera. It CAN do faster continuous motion, but I’ve not experimented with that (yet)…”

Here is the link for the MX2; http://dynamicperception.com/


As Cambot grows I’m noticing space become a bigger and bigger issue, which is why designs for overhead mounts seem more interesting to me;


And this design has been updated to be motorized and controlled via N64 controller. link

A packaged slider solution that has caught my eye is the Cinevate Pegasus;
This slider can be inverted and used as a ceiling rig, but has a weight limitation that might prevent me from mounting a jib to it.

Another slick looking camera mover is this one;Slide Jib

Another all-in-one jib/slider solution – Porta-Jib

And of course there are always Jibs link

Open source Motion Control
There are a few really inspirational projects here, all developed off the same open source hardware platform controller. It sounds a bit buggy at times but once you’ve gone through the effort of assembling it and getting it to play nice these seem fairly straight forward; http://openmoco.org/

One example of these is the seemingly well constructed and capable of driving a three-axis move; http://www.emotimo.com/index.php?option=com_content&view=article&id=46&Itemid=27

On the “low end” of the pro solutions is the DollyCrane, which integrates a slider and a jib, and has an optional MoCo driver…
Dolly Crane

These are the real deal, the big boys, way out of my budget, but worth looking into for inspiration and a basis;

Pacific motion control has a number of cranes and dollys, and encoders for programming them; http://pacificmotion.net/WP2/

Mark Roberts Motion Control- one of the industry leaders

The SFH-30, is a pan/tilt head, small and light weight,  suitable to mount to a sliding rail or ladder dolly;


Advanced Camera; shooting miniatures?

I had the unique opportunity through my work to attend a pair of lectures on using the Camera by UCLA Cinematography Professor, Bill McDonald. http://www.tft.ucla.edu/faculty/william-mcdonald/

We went over Photographic Lenses, Lens Focal Length, Camera Operating and Camera Movement, Depth of Field, Camera Movement, and Frame Composition, citing camera techniques and examples. It was a really great class and in addition to the examples he walked us through;  from films ranging from Goodfellas (zolly) to The Graduate (telephoto, wide angle, zoom lens) to Citizen Kane (depth of field) he demonstrated what he was explaining with a video camera plugged into a large monitor. So we were better able to see/visualize concepts; like the compression of space when using a telephoto lens and the increased Depth of Field  from a wide angle lens. He also talked through and demonstrated the narrative impact of camera movement  and how it unconsciously effects the experience of the film.

While I could go on about the class I feel like the most important thing to get written out right now is this question I’ve got;

How do focal length and Depth of Field relate to shooting miniatures to match with live action plates?

Specifically I want to be able to take plates of my N-scale miniatures and comp them with live action backgrounds and add actors. Do I need to convert the lens’ focal length, match the angle of view exactly?

Here is a test I made a year ago when I started thinking about these problems to see if the elements can be made to work; The tracking is terrible, color is wonky, and extraction isn’t very clean. I could tweek this endlessly to make those aspects work better, but ‘you can’t gold plate a turd’. I just need to study this and turn out more tests.

The things I’m most focused on are the issues of camera, Depth of Field, camera angle, and matching lens distortion/focal length;

The problems I’ve been running into have mostly been relating to focus, my 100mm Macro lens gives me this lovely slice of shallow Depth of Field, but that doesn’t really help me make the miniature look bigger, I just end up with this;
Out of necessity of my stage,  I’ve been shooting my miniatures with the 100mm macro, and my actor with a 14-40mm wide.


Here is what I need to know about DoF;

Shallow Depth of field;

-longer lens

-wider apeture

-closer to camera

Deep focus;

-Wide lens

-further from camera

-smaller apeture

(needs more light to accommodate for wider f-stop)

I’ve been reading Stu Maschwitz’ ‘DV Rebel’s Guide’, and recently finished the chapter on effects and matching cameras. and there is a great breakdown of a Rolling Stone video shot by David Fincher, There he explains that the camera doesn’t see anything differently between a small object or a large one apart from Depth of field.  Use the same lens (focal length). So the things to record are; distance from the model/actor, distance from the ground, and angle of the camera. Then either scale up or down the distance when you shoot the opposing part.

I suppose this makes sense, but more testing is going to be necessary.