HD Webcast Video Production: Choosing a Video Camera

Camcorder Video Cameras

The Sony PMW EX1-R

Camcorders are generally smaller video cameras that can be handheld or tripod mounted but not shoulder mounted without a shoulder-mount rig. They typically have smaller 1/4" , 1/3", or 1/2" sensors and come with a fixed video lens that requires lens adapters if you require wider or more telephoto then the lens allows. Camcorders have servo lenses so you can zoom with a zoom rocker or on the lens barrel.

Smaller sensors and fixed lenses mean lower cost, and a professional camcorder typically costs between $4,000-8,000.

PTZ CCTV or POV Cameras

Panasonic AW-HE50SN HD Integrated PTZ Camera

Pan-Tilt-Zoom (PTZ) Closed Circuit TV and Point of View (POV) video cameras are generally less expensive compared to camcorders and ENG video cameras but they lack manual controls and can have very small sensors. These cameras are generally used without an operator, although PTZ cameras can be operated remotely.

Prices for POV and PTZ cameras range from $300 for the popular GoPro Hero2 to more than $5,000 for high-end PTZ models.

Large Sensor Video Cameras

Sony NEX-FS100 video camera

When videographers started using DSLR cameras like the Canon 5DMKII to record video, a whole new trend of large-sensor video acquisition was started. The benefits of a single large-sensor video acquisition in cinematography circles is that a large sensor allows for an image with a shallow depth of field and a pleasing defocused background blur, known as bokeh. Webcasters appreciate the shallow depth of field as well as it brings focus away from a potentially bland or distracting background and onto the subject. This background blur also is very web codec-friendly; a defocused background has less bit-rate hogging detail so more bits can be allocated to the important in-focus areas of the image.

Video producers know that in live video production environments they have less control of pretty much everything, and there are no additional takes, so there are limits to how shallow a depth of field you want. An f/2.8 at the end of a 70-200mm zoom lens is too shallow when filming a speaker at a podium as the subject will go out of focus with every to-and-fro motion, but f/4.0-5.6 is more forgiving and still results in a defocused background.

Large-sensor video cameras accept a wide range of photographic lenses but they do not have any electronic servo controls, so zoom, focus, and iris are generally operated manually. Some large-sensor cameras have smart lens adapters that add back some electronic or auto functionality, but servo lens support is not yet available.

Prices for large-sensor video cameras range from $5,000 to $16,000 although lenses range from $25 thrift-store finds to $2,500 professional SLR lenses, to tens of thousands of dollars for cinema lenses.

Codecs

Intraframe SD video codecs weren't too affected by video noise, but HD long-GOP codecs like HDV struggle to average the noise pattern over their 15-frame group of pictures that long-GOP codecs use. Internal video codecs are less a concern for a live webcast as the live video output from a video camera is an uncompressed video signal before the codec compresses the image. You need to consider the internal codec and recording media only if preserving each camera's video for later editing or as a backup.

Media cost, recording length, ease of ingest, and ease of editing are also important secondary considerations. Tape-based video cameras are being phased-out but, again, the signal that comes out of the video camera is higher quality than the recorded compressed video signal, so an older HD video camera with the right video outputs can still be useful. The biggest codec consideration for webcasting is not the camera's codec but the webcasting codec. I'll cover this more in a future article in this series, but webcasting codecs are long-GOP codecs, so having less background detail and noise allow you to preserve more detail within the limited webcast bit-rate.