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STOP MOTION ANIMATION ON A BUDGET Part 4
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DSLR = Small Rigs
The relatively small size of the DSLR makes it conducive to rigging. Traditional camera moving equipment can be big, bulky and heavy, often proving counterintuitive to small sets and puppets, making access to the puppets on set a back- breaking affair. Foregoing the heavy equipment usually available, set builder Adam Weir made a few small, very simple wood & PVC pipe rigs that were small, light and yet strong enough to secure the DSLR and lens combination while minimizing it’s footprint on set. These cool little rigs allowed plenty of opportunity to pan, tilt, rotate or slide the camera’s across sets for tracking shots. The small size of the cameras and mounting rigs enabled us to get extremely close to the puppets with wide-angle lenses, without impeding access to the puppet for close-ups. There is a lot of off the shelf machine motion stuff out there, but I find with a little ingenuity, rigs for DSLR’s can be super simple, steady and secure for very little cash outlay. This is the test set up we used prior to mounting the mini cam on an aluminum plate, sliding that into the flash mount atop the camera.
As cool as the system turned out to be, it wasn’t without a few difficulties. Long exposures and deep focus dictated we shoot with very small aperture settings. The combination of tiny aperture settings, dark sets and the mini camera’s low-light limits proved persuasive in my consideration of a parallax approach next time around, as we were shooting animation reference thru theD70s viewfinder & 18-70mm zoom lens. This worked well in the tests, with a wide aperture, but once we stopped down to F11- 16, things got interesting in a horror show way. I considered shooting with the mini camera’s attached to or over the D70s lens, but settled for a ‘thru the lenses’ method with plans for tight framing and focal shifts following the movement of the characters. I felt a parallax perspective would prove more troublesome, contributing too much hair pulling for those brave souls animating, but in the end, it’s really a project/shot specific consideration.
One way to avoid parallax mishaps would be to frame slightly wide, accommodating for movement in the frame. In post, we found we could push in/ adjust up to 10% without any noticeable resolution loss, as long as the source image was RAW (zero compression, full frame). Once the frames were captured through Capture NX, these were sent to a file on a 500g external hard drive. Not that 500 gig’s was necessary, it was cheap, and so we went for larger drives. These would be handy later in the process, as the VFX folks completed shots in HD, and we needed to move everything to the online session for color correct and postproduction.
Flicker: Easy to get, hard to lose.
Here’s where that aspirin may come in handy.
There’s a bit of an anomaly prevalent with DSLR animation, referred to as the much dreaded ‘flicker effect’. This is caused by a variety of situations, a few of which I’ll address here. The hitch is when viewing several still images in rapid progression (24- 30 frames per second), versus looking at each image one at a time. Many DSLR’s have flicker issues due to the iris having to open and close for each shot, neglecting to return to it’s precise former position, thus causing an aberration in the exposure. Minute exposure variations aren’t noticeable when viewed as single images, but when strung together for rapid viewing in sequence (animation), exposure variations appear as a ‘flickering’ effect. This noise or pixilation fluctuates in the frame, seemingly more prevalent in the darker areas. The most ready explanation is due to the sensitivity of the camera’s exposure sensor chip in conjunction with the aperture and shutter speed. In DSLR’s with a manual lens, the shutter and the aperture work independently of one another, allowing adjustment between the two. The D70s we bought came with an 18-70 mm zoom, but being automatic, had no aperture ring on the barrel so we decided to lose this and replace it with a manual lens to attain the control we required in a bid negate any flickering. Going fully manual with the camera reduces the possibility of flickering, so it behooves one to go thru the steps of switching all the settings on the camera to manual.
One trick that worked well for us is to just rotate the auto lens off its contact on the camera body, rotating the lens counter clockwise a bit less than a centimeter. Keeping the lens attached to the camera body, but breaking the electric contact that sends signals to the lens. This essentially reverts an auto lens to manual, and the aperture will stay constant once set. Along with this maneuver, be sure to set everything in the camera to fully manual. This will necessitate going thru all the sub-menus, switching anything that’s in Auto mode. The camera literature will be handy here, as the sub-menu’s can be deep and elusive if you’re not careful. I dislike reading manuals as much as anyone, but it was worth the time invested.
Another cause of flicker is electrical fluctuation at the source. We had a very unstable environment to shoot in, with lots of computers, heavy-draw lighting (outside of the shooting area), and a massive air conditioning system operating off and on throughout the day causing huge fluctuations in our electrical current. This spiking and dipping in the flow of current to the lights and cameras on set caused anomalies in the exposures and lighting. It’s an old problem, and I’ve had it in loft spaces in New York, as well as office buildings. Most electrical is not set up for ‘clean’ power, so we had to find ways of moderating the current to the equipment. Shooting the animated series What It’s Like Being Alone, we got around many of the hassles with the electrical by using power scrubbers at the wall outlet, and again adding high-end surge suppressors close to the cameras. This minimalized the flicker significantly, if not removing it completely once we had the cameras properly set (switching Auto features to Manual & rotating the lenses). Any flickering we noticed was minimal and easily removed in the post process using either The Foundry’s Tinderbox plug-in De-Flicker for Adobe After Effects.
Stopping down and using longer exposures also worked well, as we maintained depth of field and sharp focus while reducing the flicker. One backfire on this was the mini cameras were pushed to their limits in allowing the animators enough image with which to animate. The mini cams don’t get any more light due to long exposures; they only get what’s coming thru the aperture, and that isn’t much at F 11–F16. The mini cameras supply a ‘live’ or active image, versus the DSLR’s cumulative exposure for a still frame. We got around it by adjusting the lighting & shutter speed to accommodate the mini camera a bit. This took some time, so I’d suggest setting aside enough time prior to shooting to allow yourself some room to work out a range of possibilities under your expected lighting palette. The mini camera’s had a Lux reading of .05, which was Ok, but I think an even lower rating would have been ideal.
Another route would be to just use the mini camera as a parallax viewer, setting it up close to the lens and in front of the camera body. I’m not a huge fan of this, as it’s tough to see what is actually in camera without continually checking the frame via the Capture NX software. One way to get around this would be to shoot wide, accommodating the parallax, and cropping the frame to adjust for any repositioning of the character. Since the RAW frame needs to be cropped for screening, be careful to include this in calculating the frame adjustments. The beauty o this maneuver is the high-resolution RAW files allow up to 10% of a push in on the image before any degradation becomes apparent. Once the film was completed, we had the opportunity to screen at AFI DALLAS during its inaugural year. This was the first time I had seen the film screened on a large, theatrical venue, so I was suitably anxious to see the results of 2 years of work.
Apparently, I was the only one worrying, as the audience was thrilled with the picture quality. Overall, the film looked fantastic on the large screen, projecting from an HD tape. Our next stop-motion film, EA Poe’s THE RAVEN is to be produced using the same system, with a few requisite tweaks of course, but definitely a DSLR- based pipeline.
In retrospect, here are few things I hadn’t mentioned earlier, but may prove useful;
1. A shooting checklist. Good to have a fall back until everyone is comfortable with the entire window switching/ frame grabbing stuff is well in hand.
2. Practice file naming conventions. Many a shot has landed in the Bin of Despair as a ‘lost’ or misplaced shot due to abstract file naming, so do yourself a favor, and work out a plan prior to starting. There will be a lot of high density storage going on and redundant/ misnamed/ misplaced files will be an equally large hassle. We nearly lost a couple of shots, and in animation as it is in live action, DIY folks really can’t afford to lose anything.
3. Voltmeter / rheostat for larger lights. The voltmeter will let you see fluctuations in the power supply just prior to shooting a frame (minimizing flicker), and the heavy-duty rheostats (not household wall dimmers) will help suppress power spikes in the line, as well. It’s a rental, but these can be bought too. Worth considering if you’re planning on a long shoot.
4. Surge suppressors. We went for the larger type with a built-in battery back up. Eyeball the surge/ spike/ drop specs carefully. Shop around as a decent version is between $90-130. Well worth having at least one on the camera/ computer power supply. Lots of these available from various electronics manufacturers & retail online.
5. Using remote capture. There are several benefits too using the computer keyboard to trigger frames grabs/ captures, the most immediate being a static camera during an exposure. It’s easy to inadvertently bump the camera after many hours into a shoot when you’re tired, addled with caffeine and your client is getting restless.Hopefully, the DVD of the film and nearly 2 hours of clips will be ready to ship this Spring 2008, just over two years from our final edit & color correct. I hope this has proven helpful in gaining some understanding of what went into the pipeline of the film.
If you have any questions, feel free to get in touch thru the film website, http://www.thepitandthependulumshortfilm.com
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