Q: I am going to shoot a Star Wars fan film with the Canon XL2 camcorder, and I was wondering if I should film the lightsaber fight at 30 frames per second. If I shot the whole movie in 24 fps and shot the fight scene in 30 fps, wouldn't it make the fight scene appear to take place in slow-motion? Should I shoot the fight scene in 30 fps or 24 fps? Thanks for taking my questions.



A: First of all, you need to remember that the primary reason for shooting at 24 frames per second is to make the video directly compatible with film on a frame-by-frame basis. Ordinarily, when you transfer a video shot at NTSC's 30 frames per second to 24-frame-per-second film, you get a slight flicker effect that detracts from the overall quality of the production; shooting at 24 fps avoids this problem.

Okay, now that that's out of the way: even if you could figure out a way to make your 24 fps video transition smoothly into the scenes shot at 30 fps (an unlikely proposition at best), you'd still be going about it the hard way. The best way to produce a slow-motion effect is to adjust the speed setting in your nonlinear editing software during editing, not while shooting. Most full-featured nonlinear editing programs–and even a few of the less-expensive variety–have a setting that allows you to dial in a precise percentage to adjust the playback speed. Thus, if you want your lightsaber duel to take place at half-speed, you simply adjust the speed setting to 50%.

Q: I got caught in the rain a few weeks ago and the LCD viewfinder on my camera got wet. I wiped it off, and there are some streaks I can't get off. What do I use to clean this? My flat-screen computer monitor is the same substance, and I can't get it cleaned right, either.

Philippe Genet


A: The most important thing to know about cleaning an LCD screen of any kind is: never use any cleaners that contain ammonia or alcohol, as they may damage the screen's plastic coating permanently. Also, you should be aware that the surface of a typical plastic LCD screen is not as hard and durable as glass, so it can become scratched if certain types of paper towels or harsh fabrics are used for cleaning. Use a soft, clean piece of cloth and a little plain water for best results. Some cleaning products (such as Meridrew Enterprises' Klear Screen, www.klearscreen.com) are available that have been designed specifically for LCD screens, but we have not tried them ourselves, so we cannot comment on their effectiveness.

Q: I am a college professor, and like most college professors these days, I make extensive use of the Web to communicate with my students. Lately, I've begun shooting and editing some of my own videos, too, and I'd like to provide them to my students via my Web page. I've got a pretty good handle on streaming video–I understand that you need to use a streaming server, and my school has one available. Now one of my colleagues tells me I don't have to use a streaming server, and that in fact the quality can be much better without it. Now I'm thoroughly confused. Can you shed some light on this for me?
Dave Kaiser

Gilroy, CA

A: Your colleague is correct. Along with the streaming method, which is best used for situations in which many (hundreds or even thousands) of users want to watch your video at the same time, there's also the "store-and-forward" method–or, as it is more commonly known, the "progressive download" method. With progressive download, the user simply downloads the video file to his or her computer, and plays it from there. If the Internet connection is fast enough to play the video as it downloads, then it is, in effect, a streaming video. The good thing about progressive download is that it tends to result in much higher quality than is possible with a streaming server; the quality is, in fact, only limited by how long you want to make your viewer wait to download the clip. The drawback: progressive download video hits the Web site's server very hard, as it is treated as any other straight HTTP download. This means that multiple users attempting to download the same huge clip at the same time can really bog down the server. If you keep your video small, and/or you know your audience will be small–say, the size of a typical college class–then progressive download is probably the best way to go.

Joe McCleskey is a media and technical specialist.