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Digital Photography Definitions (E to H)


Below are definitions to many terms which come up when reading digital camera reviews and discussions of digital photography in general.

.........Term........ Definition
EF
(Canon)
EF is the term which Canon uses to describe it's lens mount, and the lenses which are compatible with it. It is an electronic lens mount, free of mechanical levers (such as Nikon's aperture levers on their non-G lenses), which does not have the design limitations or maintenance of lenses with mechanical levers.
Electron e-. If you do any research into imaging technology, you will see this symbol. This symbol is used in reference to pixels, because they can only absorb so many electrons before the electrons overflow into neighboring pixels, which results in blooming.
ELD
(Sigma)
Extra Low Dispersion. Extraordinary Low Dispersion glass is made by Hoya, and is put in Sigma's APO lenses (and some of the non-APO lenses as well).
E-TTL
(Canon)
Evaluative-Through The Lens. This is Canon's first-generation flash technology.
E-TTL II
(Canon)
Evaluative-Through The Lens II. This is Canon's latest flash technology.
EXIF Exchangeable Image File. A JPEG-compliant program which embeds information into an image, and can be viewed by any browser or photo editor that can view JPEG images. EXIF information is usually comprised of the camera maker, model, exposure settings, whether or not a flash unit was used, focal length of lens used, firmware version of the camera, shutter speed, aperture, and many other camera settings.
Fast Lens A lens, which has a low f-number setting, such as f/2.8 or smaller, is often referred to as a "fast" lens. A "super-fast lens" could be a lens which has a f/1.8 setting.
Firewire IEEE1394; High Performance Serial Bus (older terminology). A serial bus format developed by Apple and Texas Instruments in 1995. Up to 63 devices can be configured and chained together. It's data rate is 400mb/s. Firewire is also featured in high-end digital cameras as a standard due to professional cameras having high resolution and the need for quick data transfer speeds. Many other devices such as scanners offer firewire connections.
Focal Length The distance from the center of a lens to the focal point (imager/sensor). The longer the focal length, the narrower is the Angle Of View, and the shorter the focal length, the wider the Angle Of View
FOV Field Of View. Same as Angle Of View.
FOV Crop Refers to a comparison of the Angle Of View or Field Of View, between two different camera imager formats (which can be digital or film), but more specifically, it means the physical crop of a portion of the Image Circle of the lens that is not covered by the imager. Many other names for this exist such as, Focal Length Multiplier, Field Of View Equivalency Factor (which is what I call it), FOVEF, Focal Length Multiplier, X-Factor, FOV Magnification Factor, and I'm sure I'm overlooking a few dozen other names, but FOV Crop is actually different than these, because there is a physical crop from the lens. For example, the Nikon D100 has a FOV Crop of 1.5, meaning if you put a 300mm lens on it, you would get the same Angle Of View or Field Of View as a 450mm lens on a 35mm camera. In this case, there is a physical crop. However, with lenses such as the Olympus 4/3 system and Nikon's DX lenses (to name a few), you have no physical crop due to the Image Circle matching the sensor, and there is only a different AOV. Olympus' AOV for their lenses are about 1/2 of regular 35mm lenses.
FOVEF Field Of View Equivalency Factor. It's technically NOT the same as FOV Crop, where there is a physical portion of the Image Circle of the lens that is not covered by the sensor. Instead, FOVEF covers ALL equivalencies of focal length, where you can have a physical crop or simply have a theoretical "crop". In any case, it is probably best to think in terms of the FOV Crop as a "Focal Length Equivalency" rather than actual crop.
Front-Illuminated CCD FCCD. This is a CCD which is typically found in DSLRs. Light (i.e., many many photons) strikes the CCD on the front of it, which stimulates electrons into photoelectrons. However, with this kind of construction and process, it will suffer inferior Quantum Efficiency (i.e., many less photons are detected and a majority of them "bounce" or reflect off the imager).
G
(Nikon)
A Nikon designation name, meaning the lens has no aperture ring on it, and the aperture is selected exclusively from the camera. However, these Nikon "G" lenses still have an aperture lever which must make correct contact with the appropriate camera.
GIF Graphic Interchange Format; .gif; pronounced "jiff". A file format which only supports 256 possible colors, but it is great for smaller graphics (such as emoticons, "smilies", or small animations) that do not require a wide selection of colors in order to be properly displayed. GIFs should NOT be used for image storage from your digital camera. However, you might want to consider using GIFs for your website if your images are small. CompuServe developed GIF in 1987.
GIF 89a Same as a GIF, only it allows for GIFs to be shown in sequences within one file (i.e., animations).
Hot Pixel Basically the opposite of a Dead Pixel, a hot pixel is a picture element which is inappropriately overcharged with light due to a malfunction. Hot pixels will be fairly easy to observe, since they will (or should) appear in most of your images, taken at various shutter speed settings, and will appear in the same area. If these pixels do not appear in the same, and appear randomly, then you probably have a Noise issue.
HSM
(Sigma)
Hyper Sonic Motor. This is the same type of technology as Canon's USM and Nikon's SWM. Sigma's more higher-end lenses have this designation.
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Home Reviews Forums News 2013 2012 2009 2008 2007 2006 2005 2004
RSS Feeds FOV Factor Table Sensor Sizes | Definitions: A-D E-H I-L M-P Q-U V-Z | Sitemap
Articles Archived Websites (Pre-DigitalDingus): D100 Lounge E-10 Club | Contact