Glossary of Photo Terms



TC  – Tele-converter
Add-on lenses that mount between the camera body and the lens and magnify the image from the lens as it passes through to the image plane. Not to be confused with Tele-extenders which are screwed to the front of a lens to provide a similar increase in magnification.

TIFF  – Tagged Image File Format (.tif)
TIFF was originally a 2-bit black and white format developed for early scanners and fax machines. Over the years it has evolved into a full-color standard widely used by document management programs and fax servers since the format allows the storing of multiple document pages and images in a single file.

TTL – Through The Lens
Refers to automated metering systems that sample the light passing through the lens to determine the correct exposure, even when a flash is used. Older cameras used a hand-held meter or one mounted on the front of the camera measure the correct exposure after which the camera was set manually. Early automatic flash units required the camera to be set manually and used a meter on the flash to control exposure. 

Tv Mode – Canon’s Shutter Priority Mode (Time Value)
Setting the camera to shutter-priority makes the shutter speed the primary setting and forces the camera’s metering system to adjust the Aperture (f/stop) and ISO (if it is set to Auto-ISO) to set the proper exposure. This mode gives you excellent control over controlling motion blur.

USM – Ultra-sonic Motor
Canon term for their in-lens motor technology (high-performance)

VC – Vibration Compensation -Tamron term for their lens-based image-stabilization technology

VR – Vibration Reduction -Nikon term for their lens-based image-stabilization technology

WB – White Balance -White balance refers to the adjustment made in-camera or in processing that adjusts the overal color of the image to render it correctly, usually based on a white area of the image. Hence the name. Light “color” is measured in degrees Kelvin: the “K”. The Kelvin color scale is based on the color (wavelength) of light given off by an object (originally a block of carbon) heated to specific temperatures. An object heated to 1000° K will glow a dull red but the 5000° K flame of a carbon-arc searchlight appears as bluish-white. “Daylight” is standardized at 5500° K and “Tungsten” at 3200° K to 3400° K. (Your basic 100W incandescent bulb usually has a color temperature of around 2900° K) Note that as the color temperature rises, it is considered “cooler” or bluer and as it lowers, it is considered “warmer” or more yellow/red. An odd conceptual twist that likely has its roots in the fact that this all started back when most film recorded a negative image.

X – Usually refers to a multiplier
In zoom lenses, X equals the longest focal length of the lens divided by the shortest. Example: The nikon P1000 lens has a 125x zoom – 539mm/4.3mm = 125.34
In SD or CF cards, X equals a multiple of 150kb/s (the original standard for CD players). Example: A Lexar 133x cards is rated at 20Mb/s. 133×150 = 19,950 Kb/s. 19,195 Kb/s = 19.95 Mb/s
In Neutral Density filters, X = the factor by which the incoming light is diminished. Example: ND2x reduces the light to half. ND4x reduces the light to a fourth.
In camera models X equals a holding place for a variance in a series of similar models. Example: Sony A6x00 refers to the series of A6000, A6300, A6400 and A6500.

ZA – Zeiss for A-mount
Zeiss lenses made for the Minolta/Sony A-mount. Available as top-end lenses for Minolta and Sony DSLRs (and some film SLRs). Notably the only Zeiss lenses that autofocus.

Zebras – Overexposure Warning
Zebra is a function of advanced mirrorless and video cameras (available in live-view mode on some DSLRs) that superimposes strpes over areas that are overexposed beyond the camera’s dynamic range. Parts of the image under the Zebras would come out as white areas with no detail available.

ZF – Zeiss for F-mount
Zeiss lenses made for the Nikon F-mount. These manual-focus only lenses are ultra-high quality and are generally considered to be some of the best made.

ZK – Zeiss for K-mount
Zeiss lenses made for the Pentax K-mount. These manual-focus only lenses are the same ultra-high quality as the other mounts.

ZM – Zeiss for Ikon
Zeiss lenses made for the Zeiss Ikon rangefinder camera.

ZS – Zeiss for M-42 Screw-mount
Zeiss lenses made for older M-42 screw-mount cameras. These manual-focus only lenses are not only used for older film cameras, but can be fitted with adapters to work on many newer cameras, notably the ILCs.

ZV – Zeiss for Hasselblad
Zeiss lenses made for the Hasselblad medium-format cameras. These manual-focus only lenses are used where critical sharpness is needed for the larger film format and now, larger digital sensors.