film, reflects light up to a focusing screen, so you can see the subject. The film
is positioned behind the taking lens. The two lenses are mechanically linked,
and as you focus the viewing lens (generally using a knob on the camera body),
both lenses move simultaneously. Thus, when the image on the focusing screen
is sharp, the image on the film also will be sharp.
Although not as popular as they once were, TLRs are still available, mostly
used. Almost all TLRs take medium-format film and with a few exceptions
have a nonremovable lens.
Unlike most camera types, TLRs don’t offer eye-level viewing. Instead, you
view your subject at waist or chest level, looking down at the focusing screen
to view, compose, and focus your subject. Ambient light can make the focusing
screen difficult to see, so a small pop-up viewing hood fits around the screen to
shade it from extraneous light and help make the image on the screen more visible.
There is usually a spring-mounted magnifier built into the hood for critical
focusing.
TLRs can be awkward when composing and focusing your subject, because
you see a laterally reversed image when you look down at the focusing screen.
This takes some getting used to when making adjustments to your composition.
A very few TLRs take an accessory prism viewfinder that fits on top of the
ground glass. It corrects the lateral reversal and offers eye-level viewing.
Since you don’t see through the taking lens as you do with an SLR, TLRs
must be parallax-corrected to allow the viewing lens to show what the taking
lens records. Some cameras have parallax compensation built in, but with
others you must correct parallax error manually.
Digital. A digital camera works a lot like a film camera, except it uses an electronic
sensor rather than film to capture light. Light from the subject passes
through the lens and falls on the sensor; the pattern of light recorded by the
sensor is stored as a digital file of the image either in the camera or on a removable
memory card. The digital image files can then be downloaded to a computer
or to a portable hard drive.
Most simple digital cameras function like sophisticated point-and-shoot
models. You view and compose the image either by looking through a viewfinder
window or, more commonly, seeing what the lens sees displayed on a
small LCD screen on the camera back. Most digital cameras offer a variety of
programmed exposure modes and a built-in flash, but otherwise the camera
determines focus and exposure automatically. There are digital SLRs that allow
through-the-lens viewing and focusing, and digital backs that attach to mediumformat
and large-format cameras. These are mostly for advanced and professional
photographers.
Digital cameras offer a lot of advantages. There are no film and processing
expenses, because memory cards can be used over and over again. Moreover
you can see the results immediately and delete any pictures you don’t like. You
can make prints either by downloading files to a computer and printing with a
desktop printer, or taking a memory card to a camera store or consumer lab for
high-quality hard copies from a special digital printer. You don’t even have to
make a print; the image files are easy to view on a computer monitor, burn to a
CD or other media, e-mail to a friend, or post on a Web site.
Keep in mind that there are still considerations after you take the shot with a
digital camera. The image files may need to be adjusted and manipulated in an
image editing application, such as Adobe Photoshop, and this can be timeconsuming.
Also, for best results, you must fine-tune the color consistency between
your camera, computer monitor, and printer, a process called color
management; managing black-and-white results is a little easier, but still must
be done.
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