Timelapse
- Part 1 - The Beginning
Originally written in June 2012
Starting back at Art
School I was interested in time lapse and how this captured an unseen world. I
started out manually shooting with Bolex 16mm film cameras. I used a simple
system of counting a beat and triggering the shutter manually. It was of course
quite labour intensive.
Move along a few
years after I had left University and started to work for Digital Arts Film and
TV. Digital Arts started out doing time-lapse film work and also constructed
their own motion controlled cameras. At Digital Arts I worked with a great
Cinematographer, Tony Clark who taught me lots about film and the industry. We
both went on later to create Rising Sun Pictures along with Wayne Lewis and
Gail Fuller.
Moving along to
about 7 years ago and a change of career from film to music I started to fiddle
around with digital cameras since they now had become affordable. I saw time-lapse as a great
visual partner to music I was composing
in Amongst Myselves.
My first digital
camera was the Olympus C70 / C7000. This camera was quite expensive for a
compact but it had all the vital controls - external power and total manual
control over shutter, aperture and exposure. The only thing it didn't have was
a simple way of triggering the shutter. This I had to do with a modified
infra-red trigger. The other failing of this method of shutter trigger was the
controller could only manager a minimum interval of about 3.5 seconds. All said
this was a great camera. Being a compact it didn't suffer from shutter or iris
flicker that all DSLR time-lapse people have to deal with today. Here's a link to the Timescapes.org forum talking about timelapse and flicker http://forum.timescapes.org/phpBB3/viewtopic.php?f=24&t=1871
My first
intervalometer that was used to control the Olympus camera was a simple circuit
running a 555 timer circuit which triggered the infra-red controller. This
controller I managed to velcro onto the front of the camera. The circuit came from somewhere on the web
and was for a Super-8 film camera. Here's the original scan from the magazine
that the article appeared in.
This circuit used a
simple pot for the interval timing but I wanted something that was a little
more accurate and easy to setup so I devised and calculated a system of
switches with times adjusted with trimpots. The array of trim pots was arranged
in series so if I wanted an interval time of 13 seconds I would switch on the
8, 4 and 1 second switches. To control the infrared remote I had a relay (like
the circuit diagram) attached. I would now use a opto-isolator chip.
One failing during
the construction was that I thought I got the shutter timing correct when
testing. Like a DSLR shutter trigger you need to switch the shutter on for a
very short period of time say 40ms for it to register a trigger pulse. I made
it a little too short and the shutter failed to activate every time. So I had
to change a couple of components to make the shutter pulse longer. Problem was
this also changed the interval values and I ended up replacing all the
expensive 10 turn trim pots. Apart from that it was all good.
I'd like to
highlight that today anyone can simply buy a really nice intervalometer
"knock off" on Ebay for $10 like the Canon one's I now have for this
purpose. But back in 2005 they just didn't exist.
Timelapse
- Part 2 - The Track and Dolly
After doing quite a
lot of shots with this setup I was eager to get some movement happening and to
create a dolly / track arrangement. For this I took some inspiration from Ron Dexter. A legend of the film industry
and complete gadget man. I was inspired by Ron's simple drill controlled dolly.
He'd created an on the spot motorised dolly simply using some PVC piping and a
cordless drill. It was the cordless drill which he mated with the PVC piping
via a skate wheel that got me thinking.
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| The UM7 dolly on it's track |
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| The rear view of the UM7 |
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| Closeup of the Tamiya Orbital gear box used to slow the stepper motor |
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| Front view of the UM7 |
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| Front panel of the UM7 |
What I came up with
is a variation of this idea. This is my first MOCON dolly that I named UM7-MOCON. I used a Tamiya model car
gearbox and rubber wheel. The rubber wheel simply ran on the rails using
friction to move the dolly along. It wasn't overly accurate and the backlash in
the gear box was enormous but as long as you were pushing up hill with the
dolly it was perfect. So accordingly I would always setup the track higher
(only slightly) at the end to which I was travelling to. This was connected to
a small stepper motor and controller. This in turn was controlled by a
microprocessor known as a PICAXE. As you
can see it's reasonably simple. You can choose from a set of preset intervals,
change the direction of the dolly. The panel shows other controls that weren't
ever set to work eg. Linear / Log movement controls. The PICAXE processor was quite simple and I
doubt the simple programming language could have pulled what I called a logarithmic
move off. The 2 metre long tracks were a
couple of 20mm aluminium hollow tubes with wood inners to strengthen. It was
all a little wobbly sometimes especially when it was windy. These tubes were
mounted via a couple of home made brackets onto a Manfrotto tripod and my
telescope's mount. The telescope's mount was very sturdy and helped to minimise
the wobble. To do a movement the computer didn't count the steps as the
processor had a limit number of variables which was 16 I think. So I just left
the setup to loop. I would have to time my return to the unit so that the dolly
didn't run off the end of the tracks. The PICAXE microprocessor is a very
simple BASIC computer language driven unit which worked fine for this sort of
basic work. But of course I wanted MORE !!!!
(Put a movie of the dolly in action - nice Moxam's one will be good)
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| The short lived UM9 |
Before I stepped up
to a much more flexible processor I built an intermediate version named the
UM9-INT-V2 (PICTURE ABOVE) which was planned to control the dolly and my
wonderful pan / tilt head. I had a plan for the pan / tilt head but the lack of
engineering ability kept seeing it put off. It did however manage to control my
Meade LXD75 telescope. Thanks to the work of Jay Burlage and his Milapse pan /
tilt system based around a small Meade telescope system. Jay's code led me to
dig a little deeper into the LXD75 and I managed to reverse engineer some
software that was used to control it from a PC. Simple really, just listen to
what the serial line is doing and emulate it. You can make the LXD75 pan or
tilt to 9 different speeds although only 3 are usable for time-lapse the others
are too fast.
I have now separated
the computer from the dolly. As you can see there is a sort of matrix with leds
across the top and down the sides. My goal here was for a control interface
that was simple for both the user and the PICAXE to handle. So for any specific
project I was working on, I could simply reprogram it to the new requirement.
For me the achievement here was more complex I/O control and circuit
construction. The unit is full of veroboards which I designed with the help of
TinyCAD and VeroCad. I think it was a necessary step towards the
UM12. It also has it's own small SLA battery and voltage regulator to power
either the Olympus compact camera or my new Canon 1000D DSLR. I had great plans for the UM9-INT-V2 but the
PICAXE range of processor are very basic in their abilities and quite
expensive. Then I discovered a processor which had was much better, cheaper and
great support. Later with that though.
It was also during
the stage when I had bought my first DSLR, the Canon 1000D, where I learnt the
failings of using a DSLR for timelapse which are the dredded flicker.
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| UM11-dolly2 |
At this same time I
built the UM11-Dolly2 (shown above). I
took things a little more seriously and looked towards the future for a full
system which included pan / tilt. I wanted a dolly that could do multiple
passes in both time-lapse and real-time as I had a project in mind at the time.
The accuracy is all down to the stepper with a microstepper controller running
in 3600 steps per rotation mode locked to a stretched cam belt as a drive
mechanism. It works really well. Quality stepper motors start at 200 steps per
rotation but using a microstepper controller you can get up to 25000 steps per
rotation using a method of goat sacrifice and black magic. This idea of motion
came from one of the systems I worked with back in the days of Digital Arts. Unlike the first dolly (UM7)
this unit uses bearings as wheels which run along the aluminium tracks but the
movement is all done via a cam belt and cam gear. The tracks have also been
updated to 3 metres in length and the tubing has 5mm thick walls. Unfortunately
this still needs to have 3 tripods to avoid the tracks sagging in the middle.
One of the failings of my approach is instead of the camera being mounted on a
tripod which is on a dolly I've decide to elevate the track instead. This does
make for a smaller and lighter weight dolly.
It's a habit I can't
get away from. No sooner have I finished a project, I'm starting to think of a
more complex unit to replace it. It's all a part of my learning process. But I
needed to make the UM9-INT-V2 as it was the first time I'd designed up some
boards, albeit on veroboard. The plan was now to create something with which I
could expand by means of software and the hardware would be created in the
initial place to control a more complex system of dolly, pan, tilt, lens (focus
/ zoom) and more. What was holding me back is the microprocessor, the PICAXE,
as it was never really intended for much more than a learning tool. I needed
something that was no going to limit my needs.
Timelapse
- Part 3 - The Final Frontier - well maybe ...
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| UM12vB - note the removal of the Data Entry knob and additional push buttons |
The UM12-MOCON is probably the be all and end
all for me. The initial map for this unit is to have a key frame based
time-lapse and real time motion control computer. The unit has had an upgrade
in the processor department as well. I'm now using the wonderful Arduino Mega2560
processor. Lots of memory, I/O and speed. The initial version of the software
is reasonably basic. You can set up start and end points along the dolly and
set any number of frame intervals. Much of the testing and ground work for
the final unit is done though I've only implemented this basic system. The unit
is also setup for real time which I used for the Amongst Myselves - Ambient,Landscape and Space DVD. This we shot in real-time using my new
camera, Canon 5D Mk2, in video mode and did numerous passes. It was incredible
how accurate it was. As you can see the new controller has lots of buttons and
LEDs. The programming language of the Arduino is C which is pretty straight
forward and easy to work with. The extra circuit work has grown but still
reasonably easy to work with but simpler than the previous PICAXE system. This
unit has all the I/O's to work with 6 axis of control of which could be
expanded.
Last year I splurged
out and purchased a ServoCity 785 Series Pan/Tilt head. This unit ships with servo motor
control and is intended for video work but I was confident that I could get it
working with stepper motors instead. Along with the pan / tile order I ordered
a couple of 203 tooth gears (one for the pan and one for the tilt) to help with
the step count . Along with a microstepper controller on the stepper motors
running at 3200 step per revolution I think we can get timelapse to be smooth.
I've already tested out the tilt and I've managed to get NO backlash which I
found amazing. I've a small 1kg torque stepper moving the tilt quite fast
carrying my Canon 5D along with a 17-40mm L lens. The plan for the project this
year is to get both the pan and tilt working. I'm pretty confident the Pan will
be just as easy though it's a question of the stepper motor size due to added
weight.
The question of the
track system is one of my major concerns. The weight is starting to add up. One
idea I have is to use some lighting truss with which I can attach my tracks to.
This will give me the strength and keep the tracks straight and stop any sagging.
As for the tripods beneath this weight I'm still thinking about that one. The
rest of the world elevates the camera and not the track but that leads to a
large dolly and hence large tracks. OCT 2012 UPDATE - The track has now been built which is a heavy duty ladder with the tracks mounted onto it.
So the plan for 2012
is to complete the 3 axis system. The system will be key frame based, can have
linear and smooth movements in both time-lapse and real-time. All parameters
can be animated via the key frames including interval and exposure times. Store
moves. The list is endless.
Of course now I've a
plan to change the connection between the UM12 controller and the UM11 dolly. I
was starting to worry about the number of cables the dolly would be pulling
around so... the wonderful world of wireless comes into play here. Arduino's apparently
work well with Xbees. Xbees are point-to-point wireless radio modules and
communicated over the airwaves and use basic serial protocols. So the plan is
for all the controlling to take place over the airwaves and have another
Arduino in the dolly. The controller box will do all the programming and once a
final shot movement has been previewed and accepted the data is transferred to
the dolly computer and run from their. No need for the main controller. This
then leaves the dolly with just the 24vdc power from the battery pack. Nice but
all theory at the moment.
There are some great
off the shelf units designed and made by people like Jay Burlage like the
Digital Perception dolly which runs under the Open Moco system developed for
the Arduino. But
for me part of the challenge is to make my own system and for the life of me I
can't find an affordable track / pan and tilt system.
Check out these
places for more information:-
- The forums at Timescapes.org - thanks Tom
- Arduino
- ServoCity
- Ron Dextor
- Open Moco - The Open-Source Photographic Motion-Control Community
September
2012 Update
I can happily say
that I am about 80% through the completion of the UM12vB. Yes it's version B.
I've updated the hand controller with extra keyframes, control buttons and I've
also removed the dial.
Currently I have a
full keyframe system working using a simple ease in and out method based on some code thanks to Dan Thompson which I
think may need changing in the long run. Essentially it is a point to point
system. There are 7 keyframes which are these point. What I don't have the
ability to do is to place a point within a move. This would need a more complex
bezier type system which I am willing to investigate once this system is
working. To implement a bezier system will be much easier once the system in
complete as all I will be doing is modifying the keyframe system within it's
current limits. But I will probably attempt to do bezier in the future.
The dolly or master
controller contains a ChipKit Mega32 processor which is essentially a Arduino
but running at 10 times the speed and has 256K of SRAM. This was all needed to
achieve real time movement. But I think the whole realtime movement is only
going to be good enough for previewing of timelapse shots. The whole structure
of the dolly is too large and the wobble of movement is quite excessive. I will
look into modifying the dolly structure to limit this but only if I can see the
real time method being made fully possible and usable as a filming method.
The whole wireless
process works well but I've not implemented a proper ACK and NACK system.
Although my method gets around this. The hand and master controllers are
constantly updating each other with position data which does check for
inaccuracies.
I've implement a
zoom and focus motor into the equation. I've only just recently got one of the
motors working.
The track question
has been solved. What I have done is mount the two 3 metre tracks to an
aluminium ladder which gives us the vertical strength that is needed to move
this large 10kg dolly. I've also decided that it will mostly live on the ground
with the help of small sand bags. I've a plan to test out elevating one end of
the track onto the telescope mount. This will give a nice elevation element to
shots but I will need to modify the dolly plate to counteract the angle. My
main concern here is the power of the dolly motor to be able to move this
weight at the elevated angle. Stay tuned.
Current
State - September 2012
I've just gone
through a method to smooth out the real time as much as possible in software by
loading up an array with the pulse values. I'm not so sure this is better than
the previous method of calculating on the go and that the hardware is possibly
more to blame as far as stability is concerned.
The next software
step is to implement the timelapse running routine which includes the use of
the variable interval and exposure keyframes. This should be straight forward.
The hardware front I
need to modify the focus motor assembly as I've recently replaced the motor
gear with something much smaller. I need to make up an identical zoom motor
assembly.
I've just added some
rubber to insulate the tracks from the ladder runs to avoid friction. These
need to be cable tied down. I also need to make up the middle track guide. One
concern with the ladder assemble is that it had a horizontal movement and may need
some bracing but this is reasonably easy affair. I also want to add some sort
of rubber feet at the base of the ladder. Once this is completed I can test to
see if the whole elevation method is possible and if so will continue on to
make up mods for this to work. Again the dolly will need to be modified and I
have already researched a method on how to make this assembly.
