Tuesday, November 4, 2008
Keeping Gear Safe
ATV Camera Transport • Not All JPEGs Are Equal • Out, Darned Spot! • Worn-Out Imaging
Q I live in southern Utah where there’s an extensive ATV trail system and the possibility for some unique photographs. The dust, dirt and jarring from rough trails can be incredible at times. Do you have any recommendations and tips for transporting photo gear on an ATV under these conditions?
Via the Internet
A When you’re off-road, be it on an ATV or a snowmobile, you’re subjecting your camera gear to potential damage from impact, dirt, moisture, heat and cold. You want to contain your equipment to keep it from flying off the vehicle, but you also need to protect it from the jarring and lurching frame. The best option is a carefully organized backpack that separates your equipment with adjustable inserts. You can improve on that by wrapping your most delicate pieces in a thin layer of foam, or look at the customized jackets from Camera Armor (www.cameraarmor.us). The backpack needs to stay snugly on your back while you’re in motion so that your knees and arms work as shock absorbers. If you don’t secure the backpack well, it will beat you senseless.
The newer high-quality backpacks are well sealed against most dust and moisture. I use the Lowepro Vertex AW200 pack, which offers an excellent barrier against the elements. Some modified backpacks that work like a sling and can be easily moved from back to front work well in this environment for male photographers. A larger fanny pack can be useful, also. In cleaner environments, check out the option of wearing a belt with a series of holster-type enclosures that essentially organize your gear on your body, which absorbs the jolts.
Less delicate items such as tripods can be strapped directly to the machine you’re riding, but check them often as vibrations can “unscrew” the parts; when your ballhead is 30 miles back in the snow, it’s pretty much useless.
As a side note, when working off-road in larger vehicles, take care to keep your equipment off the floor, where it will receive direct impacts. Keep it in a pack on the seat next to you, secured with a seatbelt.
Not All JPEGs Are Equal
Q Using a Canon EOS 40D with a freshly formatted 4 GB CompactFlash card, the dis-play shows that the card can store 999 images when the capture quality is set to Fine/Large. On a Nikon D200 (also a 10-megapixel camera), the same size and brand 4 GB card at the same quality setting shows fewer than 600 images can be stored. Does this mean that Canon’s image compression algorithm is more efficient than Nikon’s? Or is it that Nikon’s file contains more information/larger files, potentially producing a “better” image file?
Via the Internet
A You’re dealing with a number of variables. First, the number of images shown for an empty card is projected on the basis of an average file size and the count won’t be accurate until the card is nearly filled. For Canon, the LCD display allows only three digits, so 999 is the maximum that can be shown. An “average” large/fine file is 3.5 MB for the Canon 40D and 4.8 MB for the Nikon D200, assuming that to determine an “average” file, each company shot the same standardized target. When opened with image-editing software, either file will be approximately 30 MB. So the compression ratio for the “average” file is roughly 9:1 in the Canon and 6:1 in the Nikon. The compression ratio represents the decision of each manufacturer in balancing capture file size with the maximum image quality that can be obtained with their processors. In either case, the best quality is obtained with an unprocessed RAW file rather than a JPEG. Even RAW files are compressed, however, Nikon’s to about 2:1 (15.8 MB average) and Canon’s to about 2.5:1 (12.4 MB).
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