This is the second in a series of video focused articles. You can read the first one here.
If my previous article had you scratching your head as to why anybody would bother shooting video on a DSLR as opposed to a camcorder, hopefully this one will clear things up. After all, it’s not just still photographers who are using HDSLR’s; many videographers and filmmakers have switched to them as well, moving away from camcorders and much pricier cinema cameras. The reason for this comes down to sensor size.
Most photographers are aware of different sensor formats and how they affect the quality of a photograph. There’s full frame, APS-C, and Micro Four Thirds to name a few. The different formats (save those larger than full frame, like medium format) are usually identified by their “crop factor,” where full frame is a factor of 1.0. APS-C has a crop factor of about 1.5, and MFT is 2.0. Camcorders, however, do not follow this same pattern. A still photographer picking up a pro-level camcorder for the first time may look at it and wonder how in the world they fit a f/1.6-2.8 18x zoom in such a small package. After using it, they’ll wonder why their depth of field is so great when shooting at f/1.6. This is, of course, the result of a small sensor size. Camcorders typically use what’s called a 1/3” sensor (high end broadcast cameras may use 1/2” and lower end consumer models 1/4”). The problem is that a photographer is not thinking in terms of inches, but crop factor—or at the very best, millimeters. This makes it difficult for a still photographer to make sense of a camcorder sensor. A little bit of math (or a quick Wikipedia search) gives us the answer we want: a 1/3” camcorder sensor has a crop factor of 7.21. This means a 50mm lens—if you could mount it—would have a 360mm equivalent field of view on a standard camcorder. Yikes. The 18x zoom lens on a Canon XF 300 has an equivalent field of view of about a 28-520mm lens, but its physical measurements are 4-72mm. Hence our depth of field problem: 4mm, at any aperture, is going to have a lot of depth of field.
This is why—among other obvious reasons—your home videos don’t look anything like The King’s Speech, a feature shot on 35mm motion picture film. The larger frame size of film gives you much more control over your depth of field. This is why HDSLR’s have become so popular: their large sensor size mimics the look of film. When combined with the 24p frame rate, many viewers may not be able to tell the difference between footage from an HDSLR and true film in most circumstances. This look has become so coveted, and made available at such low cost (compared to traditional cinema cameras), that every market from YouTube to Hollywood has been flooded with HDSLR footage.
Full frame cameras, like the 5D Mark III, actually have a sensor area that is larger than a frame of 35mm motion picture film. Motion picture film is essentially the same size as 35mm still film, but because cinema cameras run the film vertically instead of horizontally, it produces a smaller frame. Coincidentally, the frame it produces is almost exactly the same size as an APS-C sensor. So, if exactly mimicking the look of film is your goal, an APS-C sensor is the way to go. (On the new full frame Nikon D4 and D800, users actually have have the option of shooting full HD video in either full frame or a “DX Crop” mode equivalent to APS-C sensors.) Because of the larger recording area, full frame HDSLR’s will allow you to achieve an even shallower depth of field, lens-for-lens, than most cinema film cameras. Remember, just because you can doesn’t mean you should: the “5D look” is a term often used to describe videos with so little depth of field that it seems like nothing is in focus at all. Sometimes, shooting a smaller sensor camera—like the affordable and surprisingly feature rich Panasonic GH2—can actually help you out by giving you a longer depth of field, while still maintaining most of the “film look.”
As I touched on last time, the problem with HDSLR’s is that, well, they were never made to be video cameras. While recording limits have improved with the new generation of cameras, documentarians may still prefer to shoot with a traditional camcorder where they can “set it and forget it.” Professional camcorders offer many features that HDSLR’s lack, most notably dual XLR inputs for high quality synchronous audio recording. XLR inputs can be added to an HDSLR with the likes of a BeachTek mixer, or asynchronously with a Zoom H4n, but those are additional accessories you have to buy and tote around with you. Camcorders also have many tools built in to assist the shooter, like false color, peaking, zebra stripes, and waveform displays. Some of these things you can make up for on an HDSLR by using an external monitor, but again, that’s another accessory purchase. In documentaries, content is king—the look is secondary. A camcorder could make your life much easier.
If this has left you wishing for the “best of both worlds” of HDSLR’s and camcorders, you’re not alone. And the camera companies are listening. Sony’s F3, FS100, and Canon’s new C300 are all interchangeable lens video cameras built around a large “Super35” sensor (roughly the same image area as APS-C). Of course, these cameras come at a pretty steep price, ranging from about $6000 to $20,000, but they are thousands cheaper than previous cinema cameras. The Sony cameras, in particular, feature a very short flange distance on the lens mount—meaning you can adapt many lenses from other manufactures to the camera, giving you the ultimate creative control.
The tool you choose for the job is up to you, but the most important thing to remember is that you have options. HDSLR’s are the hot thing right now, and their importance in the cinema scene cannot be understated. But that does not mean you need one. If you’re a still photographer, an HDSLR is probably the easiest path for you to take toward video. If you’re coming from a video background, however, it’s a good idea to think about what you’re giving up before switching from a camcorder.
Daven Mathies is a sales associate at Pro Photo Supply.
You can reach him for question or comment at firstname.lastname@example.org. He also owns 4sight Photography with fellow photographer Corey Bennet. Their work can be seen at www.4sightphoto.com.