DSLR in Documentaries - Matt’s Report from Silverdocs

The Silverdocs Film Festival and Conference is in full swing.  We’ll be filing some reviews next week, but just wanted to share a few impressions as it happens.  Contributor Matthew Radcliff attended an intriguing conference session on Tuesday - a DSLR workshop led by documentary filmmaker Steven Bognar and DP/Editor Matt Gottshalk from Alexandria-based McGee Digital Media.  Gottshalk is a noted expert on using DSLR cameras for video work and is a co-author of From Still to Motion.


The interesting factoid that started the session was a comment about Canon’s corporate split between still and video divisions. That is not surprising, by itself; I had not expected that the video-capable DSLR cameras were not made by the video division. It makes sense when I think about it, but I hadn’t thought of it before.

Steven and Matt went through a comparison of the different cameras that are available. The Canon 5D has a bigger sensor – a fact loved by many – allowing a shallower depth of field and a wider field of view; but there are advantages to choosing the Canon 7D or 60D instead. The 7D, for instance, is capable of filming up to 60 fps to achieve slow-motion footage, and can output HDMI video at full 1080 resolution. The 5D, which records in 1080, only outputs a reduced image (either 540 or 480, I missed the exact number). A third option, the Canon 60D, has the advantage of a flip-out LCD, making it much easier to get a shot that is not at eye-level.

A great bit of advice about lenses: when you set your budget for buying a DSLR kit, first pick out a high-quality lens, and then see how expensive of a camera you can afford. As Matt Gottshalk said, “glass is forever.” That lens will last a lifetime, if treated well, and will be able to be used on many future camera bodies. An even better piece of advice: you can rent lenses over the internet. Two companies mentioned were “borrowlenses.com” and “lensrentals.com”.The lens is shipped to you, and you can often get deals on renting for longer periods (a 3-day week or some such bargain). Last, do not fall sway to the numbers game. It is not necessary to have the fastest lens. It will cost extra to get an f/2 or lower lens, which is total overkill. Matt recommends you stick to the f/4 – f/5.6 range when filming.

Audio is a noted problem for the DSLR cameras. Unlike true video cameras, these were not designed for professional audio. The recommended approach is to use what is called double-system audio, where the picture and sound are recorded on two separate devices (just like in film), and then synchronized later. There are some software options to handled the sync for you, notably PluralEyes (http://www.singularsoftware.com/pluraleyes.html).The software matches the audio from the camera with a separate audio track.

Definitely don’t rely on the microphone built-in to the camera. In fact, some have had trouble with the on-board mic picking up a grinding noise from the motor of the lens, which is very close to the mic. This grinding noise then interferes with the sync. So remember, the cleaner the on-board audio, the easier to sync with your external audio recording later. (Also remember that sound travels slower than light, so if your subject’s microphone is far from the camera, there will be a lag between the audio from the camera mic and that from the subject’s mic.)

Steven and Matt showed some examples of different ISO settings, comparing how the 5D and 7D perform in low-light situations. They recommended staying below ISO 1000 for the 7D, and 1200 for the 5D. In the opposite direction, when shooting in the bright outdoors, they recommended using a variable ND filter (http://www.the-digital-picture.com/Press-Release/Tiffen-Variable-ND-Filter.aspx). Here’s how to make your own (http://www.digital-photography-school.com/create-your-own-variable-neutral-density-filter).

They shared with us some cuationary tales, such as “jellocam,” color-banding, and aliasing. Due to the CMOS type of sensor that is used in the DSLR camers (and many small video cameras as well), there is a problem known in the trade as “jellocam.” The sensor reads one horizontal line at a time, from top to bottom. The time it takes to go from top to bottom, while very fast, is not instananeous. So as the camera moves, vertical lines will appear slanted. (http://canon-7d.wonderhowto.com/corkboard/mystery-rolling-shutter-jello-cam-explained-0116250/)

In order to fit high-definition video on the little flash cards, the camera compresses the video. This compression can (and will) effect the color in your video. Smooth gradients will turn into bands of color. Aliasing is a complicated technica issue related to the number of Megapixels the camera sensor records and how they are reduced down to 19020×1080 pixels. This is an issue in all forms of digital recording and even was a problem in old-school film production. I’ll defer to Barry Green for a thorough explanation (http://www.dvxuser.com/articles/article.php/20).

The DSLR camera are built like a still camera. That is to say, they are awkward to hold when recording video which requires a steady hand for an extended period of time (i.e., longer than 1/48 of a second). But you can get various accessories to help you stabilize the camera. They had a couple of Redrock rigs for people to try after the session.There are a number of companies that make rigs and they are usually a modular system that you can customize to your needs (and easily expand as you get more needs or more money). Basically, the more points of contact between your body and the camera, the more stable it will be.

One item that Matt recommended heavily is a viewfinder, allowing you to see the LCD display easier. There are several types on the market; here are the Zacuto models (http://www.zacuto.com/z-finder-dslr-viewfinder). Another approach is to use a small monitor that is attached to your rig and receives the HDMI output from the camera. There are several companies in the market: Marshall, ikan, smallHD, and TV Logic. Matt uses TV Logic monitors.

On the post-production side of things, when working with Final Cut Pro, it is necessary to transcode the footage to another format. Two software options for transcoding are MPEG Streamclip or Grinder. Matt says that ProResLT is fine - he couldn’t see a quality difference. American University professor Larry Engel has a white paper on his “Workflow for Ingesting Canon 7D Media Into FCP” (http://www.american.edu/soc/faculty/engel.cfm) that is helpful.

Two last tips on shooting interviews that were offered. The DSLR cameras can only record for a certain time period before you need to stop and re-start recording. The camera doesn’t need to be turned off, just stop, wait a second, and then press start again. Canons can go about 12 minutes, other manufacturers have different lengths of time.Naturally, this is an issue when conducting an interview. Matt always uses two cameras, one on a wide shot and one on a close-up. He then staggers when he turns them on so that they will always be overlapped. Combined with a separate audio recorder, he won’t miss any of the interview (plus he gets two angles for the editor to cut between).

What if you only have one camera? Steven has taken to framing his interviews a little wider than normal, and then “popping in” during the edit. The quality is good enough to zoom in a little to the image, giving a slight close-up shot from the same footage. It’s worth a try, I think.

At the end of the session, they recommended a starter kit:

Canon 60D with the 18-135 mm lens $1200

Zoom H4N audio recorder $ 300

Rode NTG-2 shotgun mic $ 270

Two 8GB SD cards $ 50

extra camera battery $ 65

Sony headphones $ 84

Short XLR mic cable $ 20

Steven will be leading a second session today, on the challenges and aesthetics of DSLR cameras in documentaries (http://silverdocs.slated.com/2011/films/dslrcamerasindocumentarychallengesaestheticspart2_silverdocs2011_silverdocs2011). There will be a panel of DPs whose films are playing or have played at Silverdocs. The session is at 2pm in the Silver Spring Civic Building, Ellsworth Room.

And, if you’re in Silver Spring, don’t forget the WIFV - WALA - PGA East happy hour tonight. 5:30-7pm at McGinty’s on Ellsworth Drive in Siver Spring,  and the Docs In Progress summer Open House on Friday, from 6-10pm at the Documentary House.

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