The Craft of the HDSLR
It came as a huge surprise to everyone: the adoption of the HDSLR for serious video applications on network shows, high-end commercials, and music videos. Of course, it wasn't supposed to be this way. The intent of Canon, Panasonic, Nikon, and the others was to provide still photographers a reasonable solution for producing modest HD videos for the Web.
Now pro shooters of every stripe must necessarily look at these hybrid machines in a new and much lower-level light. For as much as we may not like the HDSLR's disruption in our coveted professional space, we must nevertheless understand its capabilities for our own survival. Any way you look at it, through it, or around it, the HDSLR has become another valuable tool in our burgeoning bag of tricks.
The relatively large sensor pixels in the HDSLR are sensitive in low light in the same way high-speed film emulsion requires less light to trigger the relatively large-grain bromide crystals. Indeed, the double-frame-size sensor in the 5D is twice the size of a 4-perf 35mm cine frame; and this greater size has its benefits.
In the first place, the CMOS imager draws only about 20 percent of the power of a comparable density CCD. For shooters this may obviate entirely the need to carry additional batteries to a location or the requirement for daily recharging. The low power draw also helps reduce heat at the imager surface, thus mitigating a major contributor of noise.
The CMOS imager is practical and economical, allowing simple cropping to HD video frame sizes 1920x1080 or 1280x720. While CCDs continue to offer markedly better performance for professional applications the CCD (analog) sensor must be clocked as a single unit and thus does not offer the flexibility or economy of design.
The narrow depth of field achievable in the HDSLR is often cited as a compelling advantage of the hybrid camera system, and this is understandable. For years, video shooters have used selective focus to help direct the viewer's attention inside the frame. A whisker-thin DOF can also be quite disturbing, however, in the case of an actor's face where the tip of the nose may be sharp but the eyes are slightly soft. Thus, the savvy shooter understands that a narrow DOF may not always be appropriate. Still as I've seen first-hand in my HDSLR workshops for Canon and Createasphere, these cameras can be effective learning tools for educating new shooters; the narrow DOF and breadth of manual controls are perfect for students hoping to grasp the basic concepts of depth of field, shutter, frame rate, resolution, and focal length.
The narrow DOF associated with the HDLSR does have a subtle advantage: The oversized imager and longer lenses required to achieve a normal field of view serve to reduce diffraction artifacts, a common weakness of all lenses at very small apertures. In cameras with tiny chipsets, the diffraction artifacts begin earlier in the F-stop range, so that shooting, say, with most 1/3in. cameras stopped down beyond f/4 or f/5.6 is never recommended due to the reduced contrast and resolution. HDSLRs, by comparison, support F-stops in the f/8-to-f/11 range without risk of incurring substantial diffraction problems.
HDSLR shooters can mitigate the negative impact of their cameras' high compression by respecting their cameras' reduced dynamic range. This means avoiding blown-out areas like overly bright windows in a dark interior set, or deep impenetrable shadows in high-contrast daylight exteriors or at night.
HDSLR shooters should therefore be sure to use adequate fill light to help lift deep shadow areas and forestall potential macroblocking and noise. I've found that a light Tiffen Black Pro-Mist or Schneider Optics Digicon can be helpful to tighten the struggling shadow areas at the bottom end of the response curve.
In general, HDSLRs exhibit substantially reduced vertical resolution, owing to the line-skipping formula employed to reduce the data load to the processor and CF media. Vertical tilts should, therefore, be performed sparinglyif at allto reduce the risk of aliasing artifacts, which may be especially apparent on a big screen.
Of course every video or still camera has its operational trade-offs. The HDSLR is no different posing its own set of challenges to shooters, most notably with respect to ergonomics, focus, audio connectivity, and workflow.
The size and shape of the HDSLR may be problematic to shooters who prefer a more traditional shoulder configuration. Both Redrock Micro and Zacuto offer a range of useful accessories including versatile shoulder rigs, for those who feel encumbered by the HDSLR's diminutive profile.
Other accessories including supplemental viewing systems to help find critical focus are also available. For recording high-quality audio, a double system may be employed utilizing an exterior recorder like the Zoom H4. The supplemental recording can be easily and elegantly synchronized to the picture using Singular Software's PluralEyes in conjunction with an NLE.
For many folks, the main advantages of the HDSLR are its relative economy and unobtrusive nature, allowing shooters to go where pro video cameras have been previously loath to tread. Try shooting with a regular-size pro video camera at the Santa Monica pier sometime and see how long you last sans permit. Those guys down there are tough and getting tougher. For many of us who shoot often under such conditions in Southern California and other places, we need new tools to help us fulfill our assignments with precision, gusto, and minimum hassle. The HDSLR can be instrumental in helping us to do exactly that.