File Format: The specific organization of data within a file. There are multiple raster and vector file formats, including TIFF, IOCA, Tiled TIFF, IGES and DXF. Some file formats have been specified for file interchange to facilitate data storage.

Filter: A specialized mini-application to extend or offer unique expansions of a software package. Usually through the use of plug-in architecture. This is a key component of many imaging software packages

Firmware: An Often-used microprogram or instruction set stored in ROM. Usually refers to the ROM-based software that controls an unit. Firmware is found in all computer based products from Cameras to Digital Peripherals

Focal Length: A lens' angle of view, most commonly indicated as wide-angle, normal or telephoto. Usually compared to a 35mm camera's lens. 

The lens in a digital camera is almost always smaller than in a 35mm SLR (single lens reflex) camera. Because of that the actual focal lengths mean little to those who are already familiar to photography. To assist in understanding, digital camera manufacturers state the focal lengths of the lenses in terms of "35mm equivalent." 

The focal length is measured in millimeters, the lens on a digital camera is marked with its focal length and this is typically a very small number such as 6 - 15mm, in traditional 35mm photography everyone is "used to" the common focal lengths of 28mm, 50mm, 200mm etc. Because the CCD in a digital camera is much smaller than a 35mm negative the lenses can be made smaller (because of this they have to be of a much higher quality), to get the true focal length you need to multiply this small size by a value called the "focal length multiplier" (this is especially important for digital SLR's which take normal 35mm lenses).

Lenses, with a range of focal lengths running from a mild wide-angle (roughly equivalent to a 35mm lens on a 35mm camera) out to a mild telephoto (slightly more than the equivalent of a 100mm lens on a 35mm camera). While you invariably pay more for a camera with zoom capability, we've found the feature very useful in real-life shooting situations.