Digital Video - November 2008 - (Page 46)

DV 101 f/2.8, it will, indeed, be represented as a perfect medium gray. Now let’s assume that you’re photographing a black wall under the same circumstances. The meter will still tell you to expose a 2.8, but the black wall will reflect only 2% of the light falling on it, so only 11 footlamberts. Shooting at a 2.8 will underexpose the wall considerably (by about three stops) and, as a result, the wall will appear black. Inversely, if you have a white wall, the incident meter will still tell you f/2.8, but now 95% of the light is reflected back, so you have 520 footlamberts entering the camera lens and, as a result, the wall will be overexposed — by about two stops — and will be represented as a white wall on the final image. A reflected, or spot, meter is the opposite. You look through a spot meter, like a small camera viewfinder, and read the light bouncing or reflecting off a subject. This means the reading is, of course, biased by the actual color and reflectivity of the subject. The spot meter, like the incident meter, assumes that you are photographing a medium gray wall — and that’s where things get tricky. Using the same scenario from above, if you have 550 fc falling on a gray wall and 100 fl reflected off (18%), the spot meter reads the 100 fl, compares that to 100 ISO and 1⁄48 second shutter speed and tells you to expose at a f/2.8. That gives you a perfect representation of that gray wall. But, when you have a black wall and the spot meter reads only 11 fl reflected off, it will compensate for that and inform you how to render the wall medium gray. The meter would then tell you to expose at a f/1. If you follow the meter’s instructions the black wall will be “properly” exposed (according to the meter) and will now appear medium gray in the final result! If you have the opposite situation, with a white wall, the meter will read the 520 fl reflecting off and tell you to expose at a 5.6, which will render that white wall — you guessed it — medium gray. This doesn’t mean that a spot meter doesn’t work; it merely requires the user to interpret the information the meter provides more so than an incident meter. There are, however, many applications where a spot meter shines, namely in measuring a light source itself, such as a practical lamp shape that is seen in the shot or a stained glass window, where an incident meter won’t work. Also, if you’re at a distance to your subject and can’t get to them, perhaps they’re wildlife or you’re on a crane, a spot meter can be used from the camera position. Together, they’re incredibly useful tools. Where a meter really shines is in recording light ratios, something you can’t do with just a monitor. If you have to return to a location at a later date and match a look, measuring your lighting ratios beforehand can save you a lot of trouble in re-creating that look. In addition, one of the most challenging lighting situations for any cinematographer is shooting a daytime exterior when you have to shoot for many hours and make it look like only a few minutes in the final result. As you constantly adjust your lighting for the moving sun and/or variable cloud coverage, you need to add fill or take away hard light, the light meter becomes your best friend for keeping the balance quickly and efficiently. In this month’s DV101 Blog entries on DV.com, I’ll be going into more depth on meters and their usage. DV ADVERTISEMENT PRODUCT SPOTLIGHT AT8004 and AT8004L Omnidirectional Dynamic Microphones Audio-Technica’s AT8004 (5.93” long) and AT8004L (9.43” long) omnidirectional dynamic microphones are ideal for on-location interviews/sports broadcasting. Each offers exceptionally natural reproduction. Internal shock mounting minimizes handling/cable noise. CONTACT: www.audio-technica.com, mediaproduction@atus.com,330-686-2600 http://www.DV.com http://www.audio-technica.com

Table of Contents Feed for the Digital Edition of Digital Video - November 2008

Digital Video - November 2008 Contents AG-HMC150 Camcorder I-Cuff Eyepiece Protector Instant Expert Avid Media Composer 3.0 DT-B9L 1DU Monitor Flolight LCD500 Dark Red Close-Up: Chop Shop Socky Prime Mover Tools & Technology: DV Expo Toolkit Click to Play DV101 Production Diary

Digital Video - November 2008

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