Time Lapse Video Secrets: HD and Beyond with your Digital Camera

Marco Solorio One River Media Walnut Creek, California, USA © 2010, CreativeCOW.net. All rights reserved.

Believe it or not, you have the ability to shoot film resolution 2K files, 1080 HD, 720 HD and standard definition video with any off-the-shelf digital SLR (DSLR) camera. Today’s full-frame sensor DSLR cameras can even go well beyond the 4K cinema resolutions, for under, and sometimes well under, $2000. Their ability to shoot HD video is revolutionary, but it is also worth remembering that these are still cameras, with features for photography that are no less amazing, including huge sensors with almost unbelievable sensitivity to light. With some experience, you can shoot time-lapse without it even looking like time-lapse. When it comes to this style of shooting, you can throw your video camera out the window. After reading this article, you'll see why DSLR technology can be superior in every way imaginable.

When it comes to time-lapse photography (AKA, "interval shooting"), there isn't a true HD video camera on the planet that'll out-perform the resolution, quality and control of your standard DSLR. The best HD video cameras only go up to 1080 HD (which by the way only equates to 2.1 mega-pixels) and the media is fairly compressed in most cases. With a DSLR, not only can you easily achieve 1080 HD resolution, you can even surpass 2K film resolution with little effort. With some high-end DSLRs on the market, you can even surpass 4K film resolution while paying only a minute fraction of what a Grass Valley Viper or Sony CineAlta rig would cost. Imagine that, greater-than-4k-resolution, 4:4:4 lossless color space, and 14-bit latitude. Sounds good to me.

It's not just a matter of frame size that makes DSLRs so much better than HD video cameras for time-lapse. It's also a matter of image formats.

With a high quality DSLR, you can shoot in RAW mode, which is basically the "raw" data taken by the image sensor (CMOS or CCD). What this brings to you is much greater flexibility in the post-production process. White balance off? No problem. Exposure slightly low? No problem. With RAW files, you can adjust image settings before they have been applied to process the final output. It's kind of like working with negative film and adjusting the levels before you create a print out of it. Of course, like anything that delivers greater quality, a RAW image will be larger in file size than its JPEG counterpart. But believe me, it's worth every extra byte. And with today’s cheap prices on large memory cards, it’s a no-brainer.

Another great benefit to shooting with a DSLR camera is glass. Nothing beats picking your lens of choice for a specific shot in mind, especially primes. With a quality, fast lens, the large DSLR's image sensor can obtain narrower DOF (Depth of Field); something a DV camera can only dream of. Low-light capabilities are also vastly improved because of this. Shooting with a huge sensor and a prime lens at f/1.2 with no lens adapters is a thing of sheer beauty.

Another interesting aspect of using DSLR versus any video camera is size. Obviously DSLR cameras are considerably smaller in size than video cameras, especially a broadcast SD or HD camera. I have a photography backpack that holds the camera, eight lenses, a large selection of filters, flash, a nifty notebook computer compartment and miscellaneous items like batteries, CF cards, cords, etc. All of this is smaller than a CineAlta HD camera itself.

GETTING STARTED

1. Shoot in RAW mode if you have the option.
2. Shoot in manual mode; both camera and lens.
3. Format your card before you start.
4. Use a battery grip pack or external power.
5. Use a good tripod on solid ground.

So, now what do you actually DO?

There are several ways to control your DSLR. Canon has a nifty digital shutter release controller (Model TC-80N3) that works perfectly with my Canon 5D Mk II and 20D (also known as an “intervalometer”). With it, you can set interval times (minimum of one second intervals) and the remote will accurately snap away as if it were you physically hitting the shutter release button.

Another useful way to shoot time-lapse is by tethering your DSLR to a computer via USB or Firewire. Canon offers free software to its DSLR users which controls every function of the camera from the software, including time-lapse recording. You can even shoot your images directly to the computer or the camera - or both!

Do check your camera’s operating manual first though as some cameras have built-in intervalometers.

If you anticipate shooting frames over an extended period of time, then saving your images direct to a notebook computer (or even to an external FireWire drive for even more space) is a powerful option. With memory cards at the current capacity of 32 GB with 64 and 128 GB on the way, external storage may not be required. As a point of reference, I can currently get about 20 seconds worth of 24p footage on a 4 GB CF card running in RAW mode at full 8.2 mega-pixel resolution.

Speaking of "control," I'd like to emphasize the use of shooting in manual mode, in both the camera's shooting mode and the focus mode. It's very important to set everything to manual or your frames may encounter sporadic exposure levels, white balance levels and so on. Don't use a single auto-function on the camera at all! This means setting your ISO, your white balance, your F-stop, your shutter speed and of course, your focus setting. If you don't know how to use those functions individually, this is the perfect time to learn. Get out the manual!


This comparison shows the amount of picture information in each of the relative formats presented.

FORMAT OPTIONS

So now that you've got a ton of time-lapse photos taking up gigs of space, what do you do with them? For me, I throw the image sequence into Adobe After Effects. It's simple; you literally drag the folder containing the images right into After Effects and it knows that it's an image sequence. If it's an image sequence based off RAW images, then a popup window will ask you for image setting options. At this point, you have to know what frame-rate you want the sequence to be in. I prefer 24, but you can work in 25 for PAL or 29.97 for NTSC. By default, After Effects will conform the image sequence to 30 FPS, so change it to suit your own preference.

Next, which resolution do you want to work in? Obviously you can make a comp running at 2K if you have the hardware to play it back, but for this example, I'll talk about 1080 HD.

Since I like working in 24p, I make a new comp at 1080p24. You can just as well make a 1080p30 or 1080i60 comp, if you so desire. If you want to work in a true 60i format, you'll need to change your image sequence (the time-lapse photos) to 60 FPS. Why? So that each interlaced field gets its own temporal data. If you don't, then you will have a 1080p30 clip even though you think you're working in 1080i60. Obviously making your clip run at 60 FPS will increase the time-lapse speed two-fold, so keep that in mind. Confused? If so, don't worry about it and work in 1080p30 or 1080p24.

Here's something amazing... When you drop the image sequence into the new comp's timeline, you'll quickly see that the frame size of the images is quite larger that the 1080 HD frame size, at least with my 21 mega-pixel full-frame camera it is. I literally have to scale my images down to 35% to work in 1080 HD. Let me say that one more time: I have to scale DOWN my images to 35% for 1080 HD!

Part of the beauty of scaling down the image is that you have two powerful options at this stage of the game: For one, you can "crop" the image sequence into the 1080 HD frame exactly how you want it (sometimes you just can't frame the shot perfectly at the location, ya know?); Secondly, by having a larger source image than that of the sequence format, you can pan-and-scan the source in the HD frame. Imagine that, pan-and-scanning for HD! With this, you can digitally pan the frame across (faking a nice and perfectly controlled pan) or you can zoom into the shot while never going above the source's 100% zoom level.

Once you finish your sequence with the right framing and any potential keyframing of pan or zoom, you're ready to output to your favorite codec of choice for your NLE. But before you do, make sure your time-lapse footage looks good on a video monitor. I do a quick RAM preview and output it through my AJA hardware, a waveform vectorscope and at least three HD monitors from CRT, plasma, LED and LCD. This combined output exam quickly gives me feedback on image quality, dynamic range, broadcast legality and so on.

FORMAT SIZES & MEGAPIXELS AT A GLANCE:

• 1280x720 - 720 HD (1 MP)
• 1920x1080 - 1080 HD (2.1 MP)
• 2048x1556 - 2K Cinema (3.2 MP)
• 2544x1696 - 4.3 MP DSLR
• 2880x2048 - D16 Video (5.9 MP)
• 3504x2336 - 8.2 MP DSLR
• 3656x2664 - Cineon/DPX (9.7 MP)
• 4368x2912 - 12.7 MP DSLR
• 4096x3112 - 4K Cinema (12.7 MP)
• 4992x3328 - 16.7 MP DSLR
• 5616x3744 – 21 MP DSLR  

WARNINGS AND PRECAUTIONS

The one thing you need to keep in mind when using a DSLR camera for time-lapse is the wear and tear you introduce to your camera’s shutter mechanism. Different quality DSLR cameras have varying shutter lifespans, which should be noted in your camera manual’s technical section. It’s this reason I still use my old Canon 20D for most time-lapse. I only use my Canon 5D Mk II when I don’t have my 20D with me, or need a shot that the 5D Mk II can truly excel better in than the 20D. Remember that as long as you’re higher than 1080 HD resolution (2.1 MP or more), you’re in good shape. Most DSLR cameras today, new and used, can easily get 8 MP or higher, like my old 20D. Better to beat on that shutter mechanism than a brand new, expensive DSLR that may not always produce drastically greater images.

GETTING ADVANCED

If you really want your footage to stand out, use camera motion control to physically pan, tilt, truck or dolly the camera for a truly compelling effect. Even though you can pan-and-scan a lock-down shot in post, that does have its limits and it won't have the same dynamic perspective that a moving camera has. Using a motorized camera tripod mount, you can achieve this slow and steady motion control. You'll need a device that works at a whopping .1° per second like the Hutech AZM-100 motorized tripod mount. It's an alt-az (altitude azimuth) astronomy mount and serves my needs for such tasks.

By using a motorized mount like this, and panning across any static subject like a clear mountain vista or a city skyscraper, will make it appear that it's not even time-lapse in the first place - making people wonder, "how did they afford to shoot this super-high resolution footage?"

Your secret is good with me.

Marco Solorio is a multi-award-winning creative media developer. He owns OneRiver Media (www.onerivermedia.com), a video and audio postproduction facility located in the San Francisco Bay Area. Marco is a longtime Creative Cow leader and contributing editor. You can find him online in our Final Cut Pro and many other forums.