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Tips on Digital Cameras & Photography |
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Tips on Digital Cameras & Photography |
Digital cameras are evolving rapidly, offering improved features every six months. Camera companies' models/prices divide into three niche markets:
For many researchers and educators, the "megapixel" cameras designed for photo hobbyists offer pleasing performance. While some features may not be used right away, it's nice to have them to "grow into."
Features can be arranged into topics for discussion, starting with a few familiar to film photography and progressing to others more unique to digital:
A built-in flash is more than convenient. It's useful for sudden picture opportunities where you need to point-and-shoot indoors. Flash-fill can reduce dark shadows in outdoor shots too. A red-eye reduction option helps reduce flash reflections from subjects' eyes in portraits and group photographs. A hot-shoe or external flash option helps when indirect lighting minimizes shadows on subjects or background and when subjects are more than twelve feet away requiring additional flash equipment.
Want to be part of the picture? A self-timer lets you get into the picture too. A timer is also useful in situations where the camera needs to be very still. Wish list item: cable release capability for shutter releases. . .
Not all pictures are at a fixed focal range. An auto-focus feature provides flexibility in your distance to target. Auto-focus works in "steps" or segments of distance. More "steps" usually allow more accurate focus. Other focus alternatives, like infinite for distances or macro for close-ups, are handy for irregular photo opportunities.
Zoom helps to compose pictures without distracting relocation by the photographer. Two types of zoom are featured in digital cameras:
Digital zoom is simply software interpolation of the original digital image. A somewhat distorted image is predictable when part of an image is isolated and enlarged by adding pixels for a zoomed-in look.
Optical zoom resizes the view using a lens before it becomes a digital image. With high-quality lenses, optical zoom performs much better than digital zoom.
Macro adjusts focal length for an extreme closeup. Again, an optical based macro outperforms any digital adjustment.
Like 35mm camera alternatives, many photographers are soon ready for filters, wide-angle and telephoto lenses. Digital cameras that accept accessory lenses permit this growth. Some cameras offer lens adapters for accessory lenses that lack integral threads. Many consumer-level digital cameras only offer a one-lens system, a plastic lens, or fail to provide even a simple lens cover for protection. Excellent image recording devices are useless when light passes through poor optics first.
Many digital cameras include a small lcd (liquid crystal display) screen that displays the exact digital image about to be recorded. The same lcd screen usually permits review of pictures on storage for instant decisions about how well pictures were captured. When an lcd screen fades in bright light situations, an optical view-finder becomes important. Look for and enjoy the best of both worlds, lcd and optical view finder, on a current digital camera.
Digital resolution, often described as width-by-height pixel counts, grows larger with each camera generation. The early 320x240 standard is basically worthless. The next 640x480 standard remains useful for VGA-quality computer screen display and is barely adequate for a 4"x6" print on paper. Current "megapixel" resolutions describe widths-times-heights that yield millions of pixels. Dimensions are less standard. A 1280x960 resolution is adequate for up to 8"x10" print with fair detail. The multi-mega pixel cameras (2.0 or greater) with 1600x1200 resolution are adequate for 11"x17" prints. By comparison, 35mm film has an image resolution of about 3600x2500 for superb visual detail.
Digital camera resolution improves as its recording component, a CCD (Charge-Coupled Device), advances technically and becomes more affordable. Be wary of how a camera conceives its "megapixel" image. Like digital zoom, a resolution tactic involves expanding a smaller recorded image to a larger one by using software interpolation, making guesses, adding pixels, and yielding blurred images with poor detail.
A "megapixel" image could take up a megabyte of storage but generally consumes 600K with a quality compressed graphic format. Even at 600K, megabytes of storage are needed for an active camera depository of 12 to 36 photos.
Cameras use different approaches to image storage:
Cameras using external memory devices or a computer are tethered to that outlet.
Cameras using their own flavor of built-in memory invite inconveniences of frequent off-loading of images and proprietary part repair or replacement.
Diskettes are practical removable storage for early 320x240 resolution, semi-practical for 640x480, but less practical now. One vendor uses the 120mb SuperDisk™, but this results in heavy, bulky, noisy, power-hungry cameras. Sony® makes a camera that records on 3.5" CD/R media.
Another removable approach uses PCMCIA fixed disk media. Three types of flash memory media are contending for camera storage acceptance:
Each uses slightly different technical concepts. SmartMedia™ relies on external controller circuitry. CompactFlash™ cards have built-in controller circuitry. SmartMedia™ has capacities from 2 to 128 megabytes (April, 2001). Earlier cameras using newer SmartMedia™ capacities require factory upgrades to their controller circuitry. CompactFlash™ keeps growing in size, up to 320 megabytes for Type I cards (April, 2001). The Memory Stick™, a gum stick sized Sony® proprietary product used in their still and video cameras, is available in sizes between 8 and 128 megabytes.
By 1998, CompactFlash™ was used in 52 cameras, 27 hand-held PCs and 19 other products like routers, disk servers, alarm systems, etc. One vendor, Lexar®, makes CompactFlash™ media that is 12x faster (1.8MB/second) than the 150KB/s standard. Another vendor, Simple Technology®, advertises speeds up to 1.5 MB/second. For more information on this key digital camera component, please visit:
A different consideration in storage is the graphic file format used to record and retain each digital image. A proprietary graphic file format, exclusive to the camera manufacturer, limits portability and requires image conversion at some point. An open and efficient format, like JPEG, conserves storage, preserves details, and enables retention or sharing without conversion.
Have you considered where you will keep all your new digital photos? Explore larger magnetic disk drives and recordable CD drives.
Digital cameras use several approaches to transfer images from the camera. Some target your computer. Some target a device like a printer or alternate storage.
One transfer strategy uses a connecting cable, a computer port (like a serial port), and computer software. Using special software applications, you direct your computer and camera to "slowly" exchange information. Generally speaking, newer USB (universal serial bus) ports are much faster than older serial ports.
Another "faster" strategy capitalizes on the standard nature of removable memory. Diskettes, used by one camera manufacturer, can be removed from that camera's drive and placed into your computer's drive. A computer might recognize SmartMedia™, CompactFlash™ or MemoryStick™ memory as a form of fixed disk when plugged into special interface cards.
Be prepared to learn more about "interface" technologies to speed up image transfer. Some cameras include a convenient PCMCIA interface card that adapts CompactFlash™ removable memory, but some don't. This common type of interface card is marketed by several CompactFlash™ brand names and ranges in price from $8 to $15 US.
The PCMCIA interface is more common on notebook computers than desktops. Removable memory can adapt to a desktop using port (parallel, SCSI, USB) interface devices, but few models are marketed. The popular SanDisk® SDDR-31 ImageMate™ adapts CompactFlash™ to a USB port and usually retails for $30 US or less.
Diversified manufacturers link their cameras with their other products, like printers. This convenience provides a quick way to render a color print if that is all you intend to do with your digital image. Several printer manufacturers offer "photo printers" designed to produce beautiful photo-like images. Some have the ability to print directly from memory cards or via an IR (infrared) port, allowing you to go from camera to print without requiring a computer between.
Digital cameras use batteries like they are going out of style. Avoid cameras that use proprietary (expensive) batteries or cells that can't be recharged. Another interesting frustration is a proprietary battery that may only be recharged in the camera.
Popular AA size cells are now offered in NiMH (Nickel Metal-Hydride) rechargeable form at a reasonable price. Nexcell® brand NiMH 1600 mAH (milli-ampere-hour) AA batteries range from $2.40 to $2.20 US each depending on quantity at Thomas Distributing or Sunn (see links trailing this paper). The mAH rating (higher being better) suggests how long a battery can last under certain load conditions. The superior NiMH construction can be recharged at any time unlike older NiCd (Nickel Cadmium) batteries that required complete discharge before recharging to sustain recharge capacity.
Several models of NiMH battery chargers are available that recharge from overnight to one hour. RadioShack® sells a one-hour charger that can be used with NiMH or NiCd cells. A less expensive but high quality recharger by Maha® (model MH-C204F, see links for Thomas Distributing or Sunn) allows one hour charging even in an automobile. By purchasing three sets of batteries, you can recharge a set while one is in use and another in reserve.
An external power connection is useful when a digital camera is in continuous use at a fixed location, like a series of portraits using flash. The built-in flash really consumes power. File transfer over a connecting cable does too.
A digital camera image may be satisfactory when displayed on a computer screen but unsatisfactory when printed. Poor print effects may come from several sources or combinations. The paper may be absorbing ink. The ink may be poor quality. The printer's resolution may be less than the image's, or the image's resolution may be less than the printer. The image graphic format may lose details or colors. The camera may record colors, hues, or details poorly. Six-color printing (Cyan, Magenta, Yellow, Black, with Light Cyan and Light Magenta or CMYK, LC, LM) produces better tonal gradation than mere CMYK (Cyan, Magenta, Yellow, Black).
Your computer screen displays at approximately 72 DPI (dots per inch) while print is capable of much more. Inadequate resolution or poor transition between solid colors or hues can amplify when printing an 8x10 size photo. Starting with a great digital camera is step one.
An All-Around Camera Recommendation
The Nikon® CoolPix 900 Series and Kodak® DC/DX camera models received many "best of show" or "best of class" awards beginning in 1998. These two camera series helped redefine digital photography and make it more useful. Both feature optical and lcd viewfinders, and both use CompactFlash™ memory.
Nikon®'s recent CoolPix 995 camera raises the bar for <$700 US digital cameras (street prices Sep, 2001) with 3.3M pixel 2048 x 1536 resolution. While still featuring a great Nikkormat™ lens with 4X optical zoom that focuses as close as 0.78 inches. Many after-market lenses, filters and adapters are available for this extremely popular digital camera. A PCMCIA adapter interface card is not included standard nor an optional external power supply.
With less features, the Kodak® DC3600 has 2.2M pixel resolution. It serves as a quality introductory digital camera with a moderate 2X optical zoom capability at prices around $280 US (street prices Sep, 2001).
Also consider these non-extension web sites for more information on digital photography:
| This page is designed for Extension Information Technology support internal to Texas Cooperative Extension . Last updated: September 25, 2001 For errors or suggestions, please contact r-rippstein@tamu.edu or p-sittler@tamu.edu "Mention or display of a trademark, proprietary product, or firm in text or figures on this page or subsequently linked pages does not constitute an endorsement by any Extension page author and does not imply approval to the exclusion of other suitable products or firms. Extension programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability or national origin." |