I'd like some help in interpreting photometric data for different brands of fresnels (at the same wattage and same bulb), specifically, the data in the B&H Lighting Sourcebook.
For the spotlight position, for example, it would seem to me that a light that projects a narrower beam with more footcandles (finer and brighter) is preferable to a light with a larger beam and/or less footcandles. Or, is this more a matter of preference or what best suits lighting a given scene?
When does the difference between footcandles become significant? When they differ by 10 (180 vs 190), or 20, for example?
In general, is photometric data a useful factor in comparing quality of different brands?

Hello Allen,
Specific photometric data is less important for videography than it might be for shooting on film. Since video is much more adjustable to lighting conditions than film specific "x footcandles at y feet" data are generally not guiding selection criteria.

The key factors when selecting lighting concern the characteristics of the light you need to provide. That is, you select your instruments much as a surgeon might select instruments; for the job at-hand. For example, diffused tungsten or flourescent intruments for soft light, fresnels or open-faced instruments for harder direct light. Wattage and lamping options within an intrument genre tend to be primary considerations for videography.

As you progress with your work you'll probably want to build a lighting kit that can adapt to nearly any requirement.

John Jackman's "Lighting for Digital Video & Television" (http://www.amazon.com/exec/obidos/tg/detail/-/1578201152/) is an excellent affordable primer on the subject.

Ken,
Thanks for your response. I've read the Jackman book and agree that it's a good one.