Glossary of Digital Photography Terms - From PHOTOS to ART with Photoshop - page 302

White Balance Color calibration for digital cameras based on light source. Standard
settings include Daylight, Shade, Flourescent, and other typical light sources. Most accur-
ately set using an 18% neutral gray card.
The Following Definitions are LENS-Manufacturer Specific and therefore, no addition-
al terms will be defined.
Canon Lenses
DO (Diffractive Optics) Compacts glass elements while keeping chromatic aberration
at a minimum. An example is Canon's EF 70-300 mm DO lens which is relatively small
and light when compared to lenses with a similar zoom range.
DW-R (Dust and Water Resistant) Most L-series lenses have this construction which
allows for shooting in rainy and snowy weather as well as other harsh conditions, such as
sandy beaches or humid jungles.
FP (Focus Preset) Focus distance is preset and instantly returned to.
FT-M (Full Time Manual focus) Manual Focus adjustments can be made even when
Autofocus is engaged.
IS - (Image Stabilizer) Employs a series of sensors and a high-speed microcomputer
to measure the vibrations and apply corrections with a specialized lens group. Most useful
when shooting hand-held at low light. Should be turned off when using a tripod. IS on/off
switch is located on the body of a lens.
I/R (Inner and Rear Focusing) Focusing is accomplished with the movement of intern-
al lens groups, eradicating extension and rotation of the front lens element. This creates
improved compactness and eases filter use.
L-series (Luxury) Canon's top-of-the-line lenses. Identified by a red line around the
front element of the lens. Image quality is second to none. Typically heavy and expensive.
Macro Lenses Can focus at extremely close distances.
STM - (Stepper Motor) Used for focusing during video recording. Better than USM at
producing smooth, precise, incremental movements needed for video capture , but slower at
focusing during photo capture.