Digital Video - July 2008 - (Page 49) ect and the choices you are making for your image. The next tool you have available is your shutter angle or your shutter speed. Shutter angle is an attribute that is available on many high-end cameras, and shutter speed is a combination of frame rate and shutter angle that is more typically available on consumer and prosumer cameras. A typical shutter angle is 180 degrees. Increasing the number opens the shutter for a longer period of time per frame of video and allows in more light. A 270-degree shutter will add 1⁄2 a stop of light to the image. Some digital cameras can shut the shutter “off” (360 degrees) to gain a full stop of light. Many consumer and prosumer cameras have shutter speed adjustments, represented in fractions of a second. This is a mathematical combination of your frame rate and your shutter angle. In many consumer and prosumer cameras, there is no option for slowing down the shutter speed, only increasing it. This won’t help you in low-light situations — in fact, it will do just the opposite and cut down on the light passing through the camera’s imager. If you can slow down the shutter speed, this will help your exposure. Slowing down the shutter speed effectively increases the shutter angle and will allow more light per frame of video. Typically the shutter speed is 2x that of your frame rate. If you’re shooting at 24 frames per second (24p), your shutter speed will typically be 1⁄48 of a second or 1⁄60 if you’re shooting 30fps. If you have the ability to “open” the shutter speed further, that will help your light levels considerably. At 24fps, 1⁄24 (or 1⁄30 at 30fps) will give you an additional stop of light. This is, effectively, doing exactly the same thing as adjusting your shutter angle, it’s just a different mathematical representation for it. As with larger shutter angles, it’s important to understand that slower shutter speeds will create some motion artifacts as you’re exposing each frame for a longer period of time, you may see more motion blur than is acceptable to you. Again, this is a personal choice. A LITTLE GOES A LONG WAY It should stand to reason, when possible, to look for areas of your location that are better lit than others. If you’re in a dark parking lot, try to stage your action around where the lot’s lights are. Any kind of light is often better than no light at all. Going a step further, you can position your talent or subject to maximize the amount of available light in a way that will be pleasing. Typically, front light is the worst for low-lighting situations. Front-lighting your subject calls attention to the lack of light in the scene and will have your audience squinting to see details in the subject. In the exact same lighting situation, if you can position your subject in such a way as to put the available light along side them, or slightly behind them, this edge-lights your talent and keeps his face in darkness, but the image becomes more readily recognized as “low light” and is more acceptable. That is now an “artistic” choice rather than a technological one. DV BUYERS MARKET COMPANY INDEX Abel Cine Tech 19; Adobe 26; AJA Video Systems 45; Apple 8, 16, 20, 32; ARRI 8; Avid 12, 16, 20, 30; B&H 19; Bebob 19; Birns & Sawyer 14; Canon 14, 18, 19, 22, 38; Cinevate 22; Dalsa 14; Deluxe Laboratories 30; Digital Film Tools 26; Edirol 40; EFilm 30; Hewlett-Packard 24; Innovision Optics 8; Iomega 34; iStockphoto 37; LaCie 34; Lensbabies 22; Lightpanels 30; Maxtor 32; MCE 34; MOTU 40; Netgear 34; Noise Industries 20; OWC 34; Panasonic 8, 28; Schneider Optics 8; Seagate 32; Sennheiser 18; Sony Electronics 8, 14, 44; Ugrip 19; Vinten 44; Western Digital 32 ADVERTISER INDEX AJA www.aja.com Avid ww.avid.com Azden www.azden.com B&H Photo www.bhphotovideo.com Barbertech Video Products www.barbertvp.com BlackMagic Design www.blackmagic-design.com Camera Dynamics www.sachtler.us Cutting Edge www.cuttingedge-sf.com Event DV www.eventdv.net Matrox www.matrox.com/video Mavric Media www.mavricmedia.com MOTU www.V3HD.com Panasonic www.panasonic.com Prompter People www.prompterpeople.com Roland Systems www.edirol.com Varizoom www.varizoom.com Videoguys www.videoguys.com 13 5 21 41-43 17 7 23 15 25 11 9 52 2 27 19 46 39 http://www.aja.com http://ww.avid.com http://www.azden.com http://www.bhphotovideo.com http://www.barbertvp.com http://www.blackmagic-design.com http://www.sachtler.us http://www.cuttingedge-sf.com http://www.eventdv.net http://www.akman.com http://www.matrox.com/video http://www.i-cuff.com http://www.mavricmedia.com http://www.V3HD.com http://www.panasonic.com http://www.prompterpeople.com http://www.edirol.com http://www.varizoom.com http://www.i-cuff.com http://www.videoguys.com
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