Storage Media Guide

As a digital photographer, I’ve come to appreciate the differences between storage media. Having to both permanently and temporarily store thousands of critical files will do that.

Undeniably, the magnetic hard disk has been the most reliable in terms of long-term storage, and yet the most volatile. It’s simply too easy to delete files by mistake. Only until recently has the problem been pretty much solved, at least in the Macintosh world. Time Machine, the OS-Native backup utility included with the Mac OS, backs up your files automatically, every hour, and maintains backups of files that were deleted. It does so very intelligently, only backing up the files that have recently changed, and only deleting previous backups if you run out of room, by which time you probably will have discovered the data you accidentally erased and and restored it. Yet it maintains this information in a user-friendly timeline format. However, this only solves the problem of your “live” or “online” storage. Eventually your hard disk will fill up, and you’ll have to find a medium on which to archive your information.

To this end, several forms of removable read/write magnetic storage media evolved. The 5.25" and 3.5" floppy disk and Iomega Zip and Bernoulli disks all employed flexible, magnetically encoded media with moderate capacity. The higher capacity Iomega Jaz, and SyQuest EZ135, EZFlyer, SyJet, SparQ and Quest drives employed rigid magnetically encoded media more like an internal hard disk. Thus they offered greater capacity and speed. All however were prone to reliability issues due to contamination by magnetic fields or dust.

Recordable optical media, which started out as the MO or Magneto-Optical disk in 1985 solved this problem. It contained sectors just like a hard drive, and as such, individual files could written and erased at will. It was very reliable, but also very slow. It used a hybrid of optical technology to erase and write data, and magnetic technology to read it. With the wide availability of CD-ROM drives, Recordable optical media eventually evolved into a purely optical media, the CD-R and CD-RW.

In this world of flash memory, aka “thumb” drives, the optical disc still reigns superior in archival storage. It’s inexpensive, reasonably stable, and unless you’re using rewritable media, cannot be accidentally erased. If you use good quality media, take your time to burn the disc at a reduced speed, and store it wisely, you will wind up with a volume that will last many years. If you develop a system of indexing the many discs that will result, you’ll be able to find data quickly.

The optical disc is now available in many different formats. Although not a sectored, read/write technology (a CD or DVD contains a single, spiral track indexed through a table of contents created when the disc is burned) advances in technology have made it fast and reliable.

Now, wrap you mind around this.

Optical storage in not a new concept. The means of analog optical storage was first invented in 1825 by Joseph Nicéphore Niépce. The 1920s saw widespread use of microfilm as an archival storage medium. By contrast, the optical disc is a digital optical storage medium. The difference is, microfilm and microfiche do not require digital to analog decoding in order to be read. Digital encoding does.

Surpassing the Optical Disc for convenience and compatibility, but not reliability, is flash memory. Flash memory is composed of microscopic capacitors, as opposed to the transistors used in conventional memory. This means that flash memory is theoretically prone to longevity issues. Failure of these capacitors after data is written will render it ureadable. Therefore, it is suitable only for short-term storage. That said however, the solid-state nature of flash memory with no moving parts increases its reliability over magnetic media, and many have reported that flash media has survived a wash and dry cycle when accidentally left in a pocket.

The advent of the flash drive employing a USB interface has launched it far ahead of any other media requiring a separate drive to be read, and it capacity is many times more than any magnetic, magneto-optical or optical storage media introduced to date.

Here’s a guide to which format to use for a given purpose:

Media	Capacity	Purpose
External Magnetic Hard Disk	Up to 10TB and beyond	High-capacity, short to long term archival data storage or backup.
DVD+R DL, DVD-R DL	8.5GB	High-capacity, long term archival data storage.
DVD+R, DVD-R	4.7GB	High-capacity, long term archival data storage.
DVD-RW	4.7GB	High capacity, mid-term data storage or backup.
CD-R	650MB, 700MB	Moderate-capacity, long term archival data storage.
CD-RW	650MB, 700MB	Moderate-capacity, mid-term data storage or backup.
USB Flash Drive	128MB-32GB	Low to high capacity, short to mid-term data storage or backup.
Secure Digital, CompactFlash, MemoryStick, MultiMedia, SmartMedia, xD-Picture Card	32MB-32GB	Low to high capacity, short to mid-term data storage or backup.

Review: Canon PowerShot SD780 IS

Walter Zapp would be proud. As you can see from the photo above, the SD780 is similar in size to the Classic Minox B, a camera that was designed “to be with you always”. But it’s shape is much more practical for those of us who are photographers and not spies.

Read more >




Pigeon Hotspot

Terms & Definitions

135 Film A still-picture film format derived from motion picture film.

A1 an ISO 216 standard paper size of 59.4 x 84.1 cm (23.4 x 33.1 in.)

A2 an ISO 216 standard paper size of 42.9 x 59.4 cm (16.9 x 23.4 in.)

Adapt A-Matic Mount A universal screw thread lens mount system introduced in 1966 by Tamron. Screw-mount Adapt A-Matic lenses are attached to various SLR cameras through the use of an Adapt A-Matic screw to bayonet mount adapter.

Adaptall Mount A universal bayonet lens mount system introduced in 1973 by Tamron. Bayonet-mount Adaptall lenses are attached to various SLR cameras through the use of an Adapt A-Matic bayonet to bayonet mount adapter.

Adobe RGB (1998) A color space developed by Adobe Systems in 1998 as a working color space which encompasses most of the colors printable with the CMYK process using RGB primaries. Adobe ’98 is also used in many professional cameras as a capture space.

AF Lens A Nikon F-mount lens type introduced in 1986, based on the AI-S lens, and containing a focus coupling on the lens mount to allow a motor within the camera body to adjust the focus automatically. This was the first series of lenses to dispense with the meter-coupling prong, which could be retrofitted for use with pre-AI cameras.

AF-D Lens A Nikon F-mount lens type introduced in 1992, based on the AF lens, but including distance information to improve performance when using flash.

AF-I Lens A Nikon F-mount lens type introduced in 1992 which features an internal motor. Unlike AF-S lenses, which feature an internal SWF (silent-wave motor), these are professional-grade super telephoto lenses designed for professional bodies.

AF-S Lens A Nikon F-mount lens type introduced in 1998, based on the AF-D lens, that incorporates a an internal silent wave motor. These lenses are compatible with entry-level bodies which do not incorporate a focusing motor and coupling.

AI Lens A Nikon F-mount lens type introduced in 1977 which features automatic indexing of the aperture. AI lenses can be distinguished by a coupling ridge on the bottom of the aperture ring, an ADR (aperture-direct readout) scale beneath the full-size aperture scale, and two extra holes in the metering prong.

AI-P Lens A Nikon F-mount lens type introduced in 1988, based on the AI-S lens but including the chip and corresponding electrical contacts of an AF lens to allow matrix metering and auto exposure modes on AF cameras.

AI-S Lens A Nikon F-mount lens type introduced in 1981 that is an AI lens with a linearized diaphragm mechanism to improve performance, especially on autofocus cameras. AI-S lenses can be distinguished by the smallest aperture (usually f/16 or f/22) appearing in orange on the aperture or ADR scale.

AOV Angle of view. Typically used to describe the field of view of a lens. In the 35mm format, a “normal” lens with a focal length of 50mm typically has an angle of view of 46°, while a wide angle lens (35mm) and telephoto lens (135mm) have angles of view of 63° and 18° respectively.

APO Apochromat, or Apochromatic. The designation given to an apochromatic lens.

achromatic lens A lens which is corrected to bring two wavelengths (typically red and blue) into focus in the same plane.

AP-70 Agfa’s designation for a chromogenic film development process used to process color negative (print) and chromogenic black and white negative (print) films.

apochromatic lens A lens with a better correction of chromatic and spherical aberration than more common lenses known as achromats. Unlike achromats, they are designed to bring all three wavelengths (red, green and blue) into focus in the same plane. This type of lens uses optical glass with special dispersive qualities such as fluoro-crown glasses, flint glasses and sometimes even liquids suspended between glass elements. Often designated “APO”.

bokeh The aesthetic quality of the blur in out-of-focus elements within a photograph, determined by the optical elements of a lens and its aperture shape. From the Japanese word boke, meaning “blur” or “haze”.

BW400CN A high-speed chromogenic black and white film manufactured by Kodak, available in ISO 400. BW400CN is processed in widely-available C-41 chemistry.

C-41 A chromogenic film development process used to process color negative (print) and chromogenic black and white negative (print) films.

CN-16 Fujifilm’s designation for a chromogenic film development process used to process color negative (print) and chromogenic black and white negative (print) films.

camera profile (also, capture profile, input profile) The color space to which an image is captured and stored by either a camera, scanner, or other capture device.

Canon EF-Mount A non-breech lock bayonet lens mount introduced in 1987 along with the Canon EOS 650 autofocus 35mm SLR. EF series lenses have no mechanical coupling between the lens and the camera body, employing electrical contacts for both aperture and focus control, along with a dedicated electric motor.

Canon EF-S-Mount A non-breech lock bayonet lens mount introduced in 2003 with a 1.6 crop factor, strictly for use with digital SLR cameras that employ sub full-frame sensors.

Canon FD-Mount A breech-lock bayonet lens mount introduced in 1971 along with the Canon F-1 SLR. The breech-lock system reduces wear on mating surfaces.

Canon FL-Mount A breech-lock bayonet lens mount introduced in 1964 along with the Canon FX camera. The breech-lock system reduces wear on mating surfaces.

Canon R-Mount A breech-lock bayonet lens mount introduced in 1959 along with the Canonflex, Canon’s first 35mm SLR. The breech-lock system reduces wear on mating surfaces.

catadioptric lens A Telephoto lens design which employs two mirrors in conjunction with refractive elements to extend the optical path, while reducing size, weight and cost compared to a refractive lens of the same focal length. Also known as “reflex” or “mirror” lenses, catadioptric lenses tend to be free from the effects of chromatic aberration, and exhibit a unique donut-shaped bokeh.

chimping CHeck IMage Preview. The practice of inspecting the LCD of a digital camera directly after image capture in order to check composition, exposure or to confirm that the desired image has be successfully captured. Often used as a substitute for metering, especially when using newer Nikon bodies with older manual focus lenses for which metering is disabled.

chromogenic A type of photographic film or paper which uses one or more layers of silver halide which react with dye couplers to form visible dyes.

chromogenic black & white film A type of black and white film which is processed with widely-available C-41 chemistry, typically used to process color negative film. Available from Kodak as BW400CN, and Ilford as XP2. Fujifilm’s version, Neopan 400CN, is not available in the US.

close-up lens Used in macro photography primarily with longer lenses, a secondary or supplementary lens that increases magnification and shortens minimum focusing distance at the expense of losing infinity focus. Close-up lenses affect image quality, but do not add to exposure times.

Contax C-Mount A bayonet lens mount standard developed for the original Contax I rangefinder. The similar Nikon S-Mount is a copy of the Contax C-Mount with a slightly different flange to film-plane distance, making some lens/camera combinations incompatible.

Contax G-Mount A bayonet lens mount developed in 1994 for the Contax G series autofocus rangefinders. The G-Mount is an all-electronic mount with no mechanical coupling to the camera.

Contax/Yashica (C/Y) Mount A bayonet lens mount standard introduced in 1975 for a new line of Contax SLR cameras, and shared with Yashica cameras.

contract proof A color proof that is usually considered to be a contract between the printer and the client as the final proof before going to press.

CLA cleaning, lubrication and adjustment.

CR-56 Fujifilm’s designation for a chromogenic film development process used to process color reversal (slide) film.

dead pixel A defective pixel, either on an image sensor or liquid crystal display, which is always off and thus appears black.

defective pixel A pixel, either on an image sensor or liquid crystal display, which is classified as “hot”, “dead” or “stuck”.

developing-out paper A type of photographic printing paper in which exposure to light forms an invisible “latent” image, which is then made visible by immersing the paper in a chemical “developer”, and made permanent by “fixing” in a second chemical bath.

Diana An inexpensive plastic camera manufactured in Hong Kong in the early sixties, and exported to the US and UK as a novelty gift item. Modern reproductions known as the Diana+ have been popularized by the Lomogoraphy movement and have subsequently achieved a cult status.

didymium A mixture of the elements praseodymium and neodymium, used in Hoya’s “Intensifier” filter, Tiffen’s “Enhancing” filter and others, for its natural tendency to enhance autumn foliage. When added to glass, these elements suppress a portion of the orange region of the color spectrum, which tend to make fall colors look “muddy”. Pronounced “dīˈdimēəm” the word originates from the Greek term for “twin element”.

diffraction The loss of sharpness or resolution caused by light being dispersed as it passes through a small aperture. Smaller apertures produce sharper images by increasing depth of field, up to the point where the softening effects of diffraction offset the gain in sharpness. Optimum aperture usually occurs from 2 stops above maximum aperture to about f/8.

DOF Depth of field. The area of sharp focus from foreground to background in a photo, as determined by aperture size.

dye destruction A photographic printing process in which pre-existing dyes within the emulsion are destroyed during processing, rather than formed as in the chromogenic process. The dye destruction process is known for its intesse colors and archival qualities. Ilfochrome is the only remaining widely available dye-destruction process.

E-6 A chromogenic film development process used to process color reversal (slide) film.

E-Series Lens A series of Nikon F-mount lenses beginning in 1979 noted for their high-quality, economical design and construction. E Series lenses contained some plastic components, and were not issued under the NIKKOR brand.

ED Glass Extra-low Dispersion Glass. A special type of glass used to reduce secondary chromatic aberration in telephoto lenses.

edge burning The practice of darkening the edges of a photo print to offset the effect of flaring caused by mounting or over matting with a white board. Edge burning helps to keep the viewer engaged by preventing their eyes from drifting out of the composition.

EOS Electro-Optical System. The three-letter designation given to the line of autofocus 35mm film and digital SLR camera system introduced in 1987 by Canon. Chosen for Eos, the Titan Goddess of dawn in Greek mythology.

extension tube Used in macro photography primarily with shorter lenses, a hollow tube without optics that extends the distance between the rear of the lens and the film plane. Increases magnification and shortens minimum focusing distance at the expense of losing infinity focus. Extension tubes add to exposure times, but do not affect image quality.

Ektachrome A range of color reversal (slide) film manufactured by Kodak and developed using the E-6 process. Ektachrome film uses integral dye couplers within the emulsion, unlike Kodachrome in which the dyes are added during the development process. It also has a higher resistance to fading during projection than Kodachrome.

EV Exposure Value. The exposure setting of the camera representing equivalent combinations of aperture and shutter. For example, at ISO 100, EV14 is equivalent to both f/8 and 1/250 sec, and f/11 at 1/125 sec. EV15 is equivalent to f/16 at 1/125, hence the Sunny 16 rule, whereby the shutter speed is the reciprocal of of the ISO value.

EVF Electronic viewfinder. A eye-level viewfinder which uses a miniature LCD display which derives its signal directly from the sensor for through-the-lens viewing. Essentially an electronic replacement for the mirror, mirror box, pentaprism or pentamirror and other components typically found in a single-lens reflex camera.

EVIL Electronic viewfinder interchangeable lens. Also known as the “mirrorless” digital camera, it replaces the mirror, mirror box and pentaprism with and electronic viewfinder for through-the-lens composition.

fisheye lens A special-purpose, super wide angle lens, with a typical angle of view of 180°. A fisheye lens can be circular, in which case its projection forms a circular image on the sensor or film, or full-frame, in which case the circular image is cropped by the frame, with the extreme corners depicting the widest angle of view.

flatness of field How the image sharpness varies from the center of the image to the edge.

foot zooming Moving toward and away from the subject in order to change its size in the composition.

FOV Field of view. The total image area a lens is capable of capturing.

Fujicolor A range of color negative (print) film manufactured by Fujifilm and developed using the C-41 or CN-16 process. Available in four different emulsions as Fujicolor 100 (general purpose), Superia (Vivid), Reala (neutral), and Pro (neutral, high contrast, high lattitude.)

Fujichrome A range of color reversal (slide) film manufactured by Fujifilm and developed using the E-6 or CR-56 process. Available in four different emulsions as Velvia (vivid), Provia (neutral), Astia (low contrast), and Sensia (low contrast).

G Lens A Nikon F-mount lens, based on the AF-S AF-S, that does away with the aperture ring, as all current camera bodies control the aperture electronically, although they still couple to the lens mechanically.

gigabit image An ultra-high resolution digital image composed of multiple smaller images “stitched” together through image editing software.

gobo Acronym for GOes Before Optics. In theatrical lighting, a device to control the shape of emitted light, which is essentially a piece of material with patterned holes placed between the light source and its optics in order to maintain sharp focus. In photography, an antiquated term for a “flags” or “cookies”, devices used to block light or create a shadows by placing them between the light source and the area being illuminated.

grid spot (also, grid). A device constructed of tubes arranged in a honeycomb configuration which is attached to the front of a flash unit to restrict light to a narrow beam. More compact than a snoot.

Holga A 120 film plastic camera introduced in China in 1981 as an inexpensive, mass-market camera for the working-class Chinese, which has been popularized by the Lomography movement and has subsequently achieved cult status.

hot pixel A defective pixel, either on an image sensor or liquid crystal display, which is always on and thus appears white.

ICC Abbreviation for International Color Consortium.

IF Internal Focus. A lens design in which only some of the internal elements move during focusing, rather than the entire lens barrel.

IS Image Stabilization. A system in which one of the lens elements is moved to counteract the effects of camera movement.

J-Mount An M39 screw thread lens mount used in early Canon Cameras. The J-Mount uses a 39mm diameter thread with a pitch of 24 turns-per-inch.

K-14 A chromogenic film development process used to process Kodachrome color reversal (slide) film.

Kodachrome A range of color reversal (slide) film manufactured by Kodak until June 2009 and developed using the K-14 process. Kodachrome film does not employ dye couplers within the emulsion, resulting in thinner layers and thus sharper images. It also has a superior archival qualities to Ektachrome, although it is susceptible to fading during projection.

L*a*b* An opponent-color space which separates colors into separate channels for luminosity and chromaticity. L*a*b* is a close cousin of the RGB color space, and can be used to achieve processing objectives not possible in other color spaces. Color is represented by the opponent channels a (green/magenta) and b (yellow/blue), while luminosity is represented by L. Because luminosity can be adjusted independently of hue and saturation, colors can be achieved that are theoretically impossible.

LCD Liquid crystal display. A back lit color display used to view photos, and in many instances as a substitute for an optical viewfinder when taking photos.

Leica M-Mount A bayonet lens mount standard introduced by Leica in 1954 along with the Leica M3 Rangefinder, also used in the Minolta CLE and Konica Hexar RF and current models Leica M9, Leica M7, Zeiss Ikon and Voigtländer Bessa rangefinders.

Lomo LC-A A manual-focus, automatic exposure camera manufactured in Russia as a copy of the Cosina CX-2, popularized by the Lomography movement.

Lomography A casual, “shoot from the hip” style of photography using inexpensive, instamatic, point-and-shoot or “toy” cameras. Lomographic photos incorporate such “Lo-Fi” characteristics as saturated colors, high contrast, soft focus, chromatic aberration, film grain, and vignetting. The origin of the term originates from the former state run optics manufacturer LOMO PLC of Saint Petersburg, Russia. Lomography is also the commercial trademark of Lomographische AG, Austria, a company specializing in photographic products and services.

long photo A short video clip with photographic qualities, often taken with a video-enabled DSLR.

lp/mm Linear Pairs per Millimeter. A measurement of lens resolution which is half of the lw/mm.

lw/mm Line Widths per Millimeter. A measurement of lens resolution which is double the lp/mm.

lp/ih Line Pairs per Image Height A measurement of system (lens/sensor) resolution which is the product of lens resolution and sensor or film frame height.

LV Light Value. The measurement of light reflecting from an object.

M39 Mount A screw thread lens mount used primarily for Leica rangefinder cameras, and also for enlargers. The Leica mount, also known as the LTM, has a 39mm diameter thread with a pitch of 26 turns-per-inch (Whitworth) approximately 0.977mm. Soviet cameras used a similar mount with a pitch of  1mm, while early Canon cameras used a pitch of 24 tpi, called the J-Mount.

M42 Mount A screw thread lens mount standard developed in 1949 and introduced with the Contax S 35mm SLR. The M42 Mount uses a 42mm diameter thread with a pitch of 1mm, making it incompatible with Tamron’s T-Mount system, with which it shares the same thread diameter. Also known as the Praktica Thread Mount, Universal Thread Mount and Pentax Thread Mount.

MC Multicoated. A lens design with several different lens coatings to minimize flaring, ghosting, and improve light transmission.

mirrorless camera A digital camera which does not employ an optical reflex viewfinder, mirror, mirror box, pentaprism or pentamirror. Usually reserved for micro four thirds or APS-C sensor cameras with interchangeable lenses.

MR-9 An adapter used to convert a 386 1.5V silver oxide battery for use in older cameras and light meters that use the now outlawed PX625, PX13, PX675, or RM400R mercury battery. The adapter not only alters the physical size of the battery, but also drops the voltage from 1.5V to 1.35V to assure meter accuracy.

MTF Modulation Transfer Function. A measurement of lens resolution.

Nikon F-Mount A bayonet lens mount standard developed by Nikon in by 1959 for its SLR cameras. Noted for its longer 46.5mm flange to focal-plane distance, making it impossible to adapt Nikon bodies to other lens systems without addition optical elements. However, Nikkor lenses themselves are easily adapted to other bodies. The Nikon F-Mount is still in use today and is well known for its forward and backward compatibility, having survived four lens mount changes by Canon.

Nikon S-Mount A bayonet lens mount standard developed for Nikon Rangefinder cameras (Nikon I, Nikon M, Nikon S, Nikon S2), which is essentially a copy of the Contax C-Mount, but having a slightly different flange to film-plane distance  making some lens/camera combinations incompatible.

the Nikon shuffle On the Nikon F2, the practice of turning the aperture ring on the lens back and forth to the lowest aperture and then to the largest aperture to assure that the lens is properly coupled with the Photomic head (viewfinder).

nitrate film A highly flammable film whose base is made from cellulose nitrate, the main ingredient in smokeless gunpowder. Nitrate film is self-decomposing and prone to spontaneous combustion. It was commonly used as movie film, including 35mm.

output profile The color profile of a destination device, such as a printer, color display or film recorder.

OVF Optical Viewfinder. An optical device for estimating the composition of the image to be taken, and in the case of a single-lens reflex camera, for previewing focus and depth of field free of the affects of parallax.

parallax The apparent displacement of an image viewed through a non-TTL viewfinder.

pellicle mirror A fixed, semi-transparent mirror used in place of a movable mirror in an SLR camera to increase the frame rate of fast sequence shooting, and eliminate finder blackout during exposure.

Pentax K-Mount A bayonet lens mount standard developed in 1975 for its SLR cameras.

photog Abbreviation for photographer.

photograph An image captured with a camera that possesses some sort of creative, historical or thought-provoking significance.

Photomic The designation given to the Nikon F2 when fitted with viewfinders (heads) that incorporate light meters.

premedia The term that is used in the design, creative and publishing industries for the processes and procedures that occur between the conception of original artwork and the manufacturing of final output channel.

printing-out paper A type of photographic printing paper in which exposure to light produces a visible  image directly, which is then made permanent by “fixing” in a chemical bath.

ProPhoto RGB A color space developed by Kodak with a large gamut able to store 90% of possible colors in the CIE L*a*b* color space. ProPhoto is specifically designed as a working space to meet the requirements of professional photographers using a wide assortment of capture devices.

psuedo TLR A variant of the twin-lens reflex camera in which the focus is fixed and the separate optical system for the viewfinder used only for composition.

pull processing The intentional under development of film to compensate for over exposure in the camera in order to decrease a film’s sensitivity. Pull processing decreases contrast, saturation and grain, and may result in color shifts.

push processing The intentional over development of film to compensate for underexposure in the camera in order to increase a film’s sensitivity. Sometimes referred to as uprating. Push processing increases contrast, saturation and grain, and may result in color shifts.

PX625 A very common type of 1.35V mercury oxide battery used in many cameras released during the sixties and seventies, discontinued when batteries containing mercury were outlawed in the United States. It has since been replaced by the inexpensive Wein MRB625 Zinc-Air battery.

RF Rear Focusing. A lens design in which only the rear elements are used in focusing, rather than the entire lens barrel.

redscale The practice of loading film into a camera with the emulsion side facing backwards, in order to expose the film’s red layer first, resulting in a strong shift toward red. Often used in lomography.

refractive lens A lens design which employs one or more elements which converge or diverge the light that they transmit. Compare with catadioptric lenses, which also employs a system of mirror to reduce the number or size of refractive elements.

Rembrandt lighting A lighting technique used in portrait photography in which the key light is placed high and to one side in front of the subject, and the fill light, approximately half the power of the key light, placed at half-height on the opposite side at the front. Rembrandt lighting is characterized by the inverted triangle that appears below the eye on the side of the face opposite the key light.

safety film A fireproof film whose base is composed of acetate, rather than nitrate. All modern films are safety film.

SC Single coated. A lens design in which only one coating is employed to reduce flaring, ghosting and to improve light transmission.

SLR Single-lens reflex. A type of camera which incorporates a movable (and in some cases semi-transparent fixed) mirror that redirects the image from the taking lens to the viewfinder for through-the-lens composition. Eliminates parallax error and allows depth of field preview.

snapshot An image captured with a camera which casually and informally documents everyday life.

stuck pixel A defective pixel, either on an image sensor or liquid crystal display, which is stuck in either an on (white) or off (black) condition.

sRGB Standard RGB, a color space developed in 1996 jointly by HP and Microsoft, to be the standard color space for computer displays, desktop color printers, capture devices, and the web. sRGB can be considered both a a capture (camera, input) and output profile.

spherochromatism The variation of spherical aberration with color of light.

sprocket hole A style of photography where 35mm film is exposed in such a way as to capture the image across the entire surface of the film, including the area where the sprocket holes exist. This is often achieved by loading film into a camera which normally accepts wider film stock, such as 120 format film. It can also be used to re-purpose vintage cameras for which film stock is no longer available.

snoot A long, hollow tube attached to the front of a flash to restrict light to a narrow beam. Less complex than a grid spot.

Sunny 16 Rule A means to determine the correct exposure value for sunny lighting conditions of LV15, which correspond to an EV of 15. EV15 is equivalent to an aperture of f/16 at a shutter speed that is the reciprocal of the ISO film speed being used. For ISO 100 film, the combination of f/16 at 1/125 sec would yield the correct exposure on a sunny day.

tagged The condition in which an ICC color profile has been embedded within an image file, in order to instruct the host application how to interpret its color based in the color space in which it exists.

telecentric A lens design in which the aperture is placed at one of its focal points, in order to generate rays which are parallel to the optical center of the lens. In lens designs optimized for D-LSRs, the len’s exit “pupil” (aperture) is said to occur at infinity, and the light rays exiting the lens strike the sensor surface at zero angle of incidence (“straight on”), minimizing vignetting and color crosstalk caused by the recessed photosites.

TLR Twin-lens reflex. A camera design which uses a separate optical system as a viewfinder, mimicking the taking lens in such a way as to preview both composition and focusing information.

T-MAX A panchromatic black and white film manufactured by Eastman Kodak, available in speeds of 100, 400 and 3200 ISO. T-MAX P3200 is actually a multi-speed film with a nominal speed of ISO 800. T-MAX can be processed with T-MAX, T-MAX RS, XTOL, D-76, HC-110 and DURAFLO RT developers.

T-Mount A screw thread lens mount system developed by Tamron in 1957 for a line of aftermarket camera lenses designed to fit a variety of camera through the use of an adapter known as a T-Mount Adapter.  Its flange to focal plane distance of 55mm makes it compatible with a wide range of cameras. However, since it uses a 42mm diameter thread with a 0.75mm pitch, it is incompatible with the M42-Mount system.

Tri-X A high-speed black and white film manufactured by Eastman Kodak, available in speeds of ISO 400 (35mm and 120) and ISO 320 (sheet film.) Tri-X can be processed with T-Max, T-Max RS, XTOL, HC-110, D-76, Microdol-X, DK-50 and Duraflo RT developers.

TTL Through-the-lens. A term used describe the characteristics of a single-lens-reflex camera viewfinder, or exposure metering performed from light gathered by the taking lens.

TTV Through-the-viewfinder. A creative form of photography in which the image is captured by photographing it through the viewfinder of another camera, typically a psuedo-TLR.

VR Vibration Reduction. A system in which one of the lens elements is moved to counteract the effects of camera movement.

waterhouse stop A device used for controlling the entry of light into a camera, consisting of a plate with a single hole or several holes of varying sizes. The plate with the desired aperture is inserted into the lens, or a mechanism operated to slide the appropriately-sized hole into place. Invented by the 19th century photographer, John Waterhouse in 1858.

working space A standardized color space to which an image is converted for post-processing.

XP2 A high-speed chromogenic Black & White film manufactured by Ilford, available in ISO 400. XP2 is processed in widely-available C-41 chemistry.

X-Pro Abbreviation for Cross-Process, the practice of processing film in an alternate chemistry to obtain special false-color effects. Color reversal (transparency) film, normally processed E-6 is processed C-41, while color negative film, normally processed C-41, is processed E-6.

The Camera

The camera, in its most basic form, started out simply as a box with an opening in it to allow light to enter. It was used as a drawing aid in the form of a “camera obscura” (dark room) to project a scene onto a ground glass for tracing. It is the ability to record this information in an objective way that has made the camera what it is today.

One way of thinking of a camera is as an attachment point for a lens. Camera bodies will come and go, but a lens can last a lifetime, so it’s important to choose a camera “system” wisely. Lens mounts differ between brands, and so not every lens will fit every camera, although many may be adapted. For example, a Nikon lens purchased with the Nikon F in 1959 can still be used on a brand new Nikon autofocus digital SLR body, and that same lens could easily be adapted to fit on a Canon digital SLR.

Of course, many cameras come without interchangeable lenses, which means that as soon as the camera technology becomes obsolete, so does the lens. This is even more true of digital cameras which due to the fast pace of technology become obsolete more quickly.

The most variable factor with film cameras has been the film. Over the years, many different film sizes have been produced, and when they are retired, the cameras that use them become somewhat obsolete. I say somewhat, because many have extended their lives by adapting them to newer films which are currently available.

The most sophisticated technology in an interchangeable-lens, mechanical film camera was the shutter. Once auto exposure came into being, and with it the onset of electronics, the exposure system was the significant factor. Autofocus was next, and even more sophistication in autoexposure, where the camera contains reference information of literally thousands of different exposure scenarios. Still with all this technological advancement, the camera body remains the component with the least longevity and resale value.

Fixed-lens cameras have a different dynamic. As new models are introduced, some become obsolete and disposable, while others may become classic and collectible. Older mechanical cameras may still be worth servicing and maintaining, while for electronic digital cameras, there is simply no repair path. So, if you are particularly fond of your digital camera, take good care of it until you are ready to part with it. They are not as durable as their mechanical ancestors.

You can easily make a camera yourself, and this ability has lead to a significant movement in photography through the use of the pinhole camera. Take a suitable lightproof container, place an aperture the size of a pinhole at one end and a means of capturing an image at the other, and you have a pinhole camera. An aperture the size of a pinhole behaves like a lens stopped way, way down, and as such has infinite depth of field. So much in fact that focusing is not necessary.

The iconic pinhole camera is a cardboard oatmeal container with a pinhole made in aluminum foil on one side, and a piece of photographic paper taped to the other. The resulting paper negative is contact-printed onto another piece of photo paper, or using today’s technology, simply scanned and inverted. Taken to the other extreme, a sophisticated camera can be constructed of wood using 4x5 or larger sheet-film holders and precise, laser-drilled pinholes that create spectacular time-exposure photographs.

Cameras come in many different designs which are suited to different purposes.

The view camera is essentially a large bellows with a lens board on one end, and a sheet film holder at the other. Although primarily used for studio work, the more portable field camera can be taken on location to capture incredibly sharp and detailed landscapes. The lens and shutter are combined into a single unit, and a ground glass used in place of the film holder for focusing and composition, not unlike the LCD of a modern digital camera. Because the front and back of the camera can tilt and shift, perspective control and depth of field enhancement are built-in. Digital image capture is accomplished by replacing the film holder with a digital back.

The medium-format camera takes 120 or 220 roll film, or has a sensor larger than 24mm x 36mm. They come in SLR, TLR, rangefinder and viewfinder designs. Digital image capture is accomplished by replacing the film holder with a digital back, and integrated digital models are becoming popular.

The SLR or single-lens reflex is a TTL (through-the-lens) design which employs a mirror (the reflex part) to divert the image to the viewfinder for focus and composition. To take the picture, the mirror flips up and the shutter opens to expose the film. This enables the photographer to preview focus, composition and depth of field exactly as they will appear in the photograph, all in the same view. Digital image capture is accomplished by purchasing a digital SLR body that is compatible with your existing range (if any) of interchangeable SLR lenses.

The TLR, or twin-lens reflex uses two optical systems in unison, one for previewing the image, and one for capturing it. When one is in focus, so is the other, but parallax error and the inability to preview depth of field still remain an issue. TLRs typically do not employ interchangeable lenses, although one model, the Mamiya C330, did. There are no commercially-available options for digital image capture, although some have experimented with shooting the ground glass of the viewfinder.

The rangefinder camera surpasses the SLR in both quality and compactness, and uses a rangefinder, sometimes with an integrated viewfinder, to determine focus. However, depth of field preview is not possible, and unless specifically corrected for, parallax still remain an issue. Due to the elimination of the mirror box, the lenses, which are usually interchangeable, are set closer to the film plane and therefore more compact and accurate. There is currently only one model of digital rangefinder, the Leica M9.

The manual-focus viewfinder camera is the most economical to produce, combining an uncoupled optical viewfinder with a simple zone-focusing system. The subject-to-camera distance is measured or estimated and set on a focus scale on the camera’s fixed lens. Some cameras employ a small enough aperture that the range of sharp focus extends from about 10 feet to infinity. These single-zone cameras are known as fixed-focus. There are no commercially-available options for digital image capture.

The auto-focus viewfinder camera is the precursor to the modern digital camera. Combining a sophisticated auto-focus and auto exposure system with a fixed zoom lens, it is just one step away from the modern compact digital camera as we know it today.

The “compact” digital camera may or may not employ an optical viewfinder, but almost always uses an LCD display to preview the image to be captured as well as review those that already have. Although this is technically a TTL system, the resolution of the LCD display may be insufficient as a means of focus and depth-of-field preview.

The “bridge” digital camera is a more sophisticated version of the compact digital camera, with greater control over exposure and focus, and often employing an optical viewfinder. It has the physical appearance and layout of a compact rangefinder. Like the compact digital, it also contains an LCD which can be used to preview and review images.

The “super-zoom” digital camera is a more sophisticated, less compact version of the bridge camera. Super zooms have the physical appearance and layout of an SLR, but as the name suggests have a fixed zoom lens of unusually wide range. They use an electronic viewfinder in place of the reflex mirror for more reliable, TTL composition under bright conditions.

The “mirrorless” digital camera is an interchangeable lens camera that is more compact than a super zoom but with quality rivaling that of a DSLR. Its closest cousin in the film world would be the rangefinder. Many of these cameras are based on the micro-four thirds standard employing a 17mm x 13mm sensor (half the width and height of 35mm or full-frame digital). While the LCD is used primarily for composition, many also have optional, detachable electronic viewfinders, not unlike a rangefinder.

All digital cameras (with the exception of the Leica M9) are auto focus, auto exposure cameras, but may have limited manual exposure and even more limited manual focus capability.

Film cameras may or may not have auto exposure or auto focus, depending largely on their date of manufacture.

A quick guide to camera types and their uses. Keep in mind that any camera can be used for any purpose; it’s not the equipment so much as the photographer using it that makes the photo. However, as an example, a 35mm or digital SLR with an available tilt-shift perspective control lens may be more suitable for those shooting architecture than say a mirrorless digital camera with nearly the same optical quality.

View Camera - Studio, product, fashion, portraits

Field Camera - Landscape, architecture, portraits

Medium Format SLR - Fashion, product, portraits, landscape, nature, architecture, sports

Medium Format TLR - landscape, portraits, snapshots

Small Format SLR - Fashion, product, portraits, architecture, nature, sports, snapshots

Rangefinder - Landscape, nature, portraits, photojournalism, snapshots

Viewfinder - Lomography, snapshots

Compact Digital - Snapshots

Bridge Camera - Product, nature, portraits, snapshots

Superzoom - Product, nature, portraits, snapshots

Mirrorless - Landscape, nature, portraits, photojournalism, snapshots

Flange Focal Distances

Mount	Flange focal distance
Pentax Q mount	9.20 mm
C-mount (Bolex, Eclair and Bell & Howell)	17.52 mm
Sony E-mount	18.00 mm
Micro Four Thirds System	20.00 mm
Samsung NX mount	25.50 mm
RED ONE interchangeable mount	27.30 mm
Leica M mount	27.80 mm
M39 (Leica) Screwmount	28.80 mm
Contax G	29.00 mm
Olympus Four Thirds System	38.67 mm
Konica AR	40.70 mm
Canon FL	42.00 mm
Canon FD mount	42.00 mm
Start (Soviet SLR)	42.00 mm
Minolta SR mount	43.50 mm
Fujica X bayonet	43.50 mm
Canon EF mount	44.00 mm
Canon EF-S mount	44.00 mm
Praktica B mount	44.00 mm
Sigma's SA mount	44.00 mm
Minolta/Sony A mount	44.50 mm
Pentax K mount	45.46 mm
M42	45.46 mm
Contax C/Y Mount	45.50 mm
Olympus OM mount	46.00 mm
Nikon F-mount	46.50 mm
Leica R mount	47.00 mm
Arri PL	52.00 mm
T mount	55.00 mm
OCT-19	61.00 mm
Mamiya 654	63.30 mm

Sensor Sizes

			Sensor (mm)
Type	Aspect Ratio	Dia. (mm)	Diagonal	Width	Height
1/3.6"	4:3	7.056	5.000	4.000	3.000
1/3.2"	4:3	7.938	5.680	4.536	3.416
1/3"	4:3	8.467	6.000	4.800	3.600
1/2.7"	4:3	9.407	6.721	5.371	4.035
1/2.5"	4:3	10.160	7.182	5.760	4.290
1/2.3"	4:3	11.044	7.70	6.16	4.62
1/2"	4:3	12.700	8.000	6.400	4.800
1/1.8"	4:3	14.111	8.933	7.176	5.319
1/1.7"	4:3	14.941	9.500	7.600	5.700
2/3"	4:3	16.933	11.000	8.800	6.600
1"	4:3	25.400	16.000	12.800	9.600
4/3"	4:3	33.867	22.500	18.000	13.500
1.8" (*)	3:2	45.720	28.400	23.700	15.700
35 mm film	3:2	n/a	43.300	36.000	24.000

The Lens

The lens is the part of the camera which gathers light from the scene to be captured and projects it onto the film or sensor.

Because a single lens element is prone to distortion, additional elements are added to correct for these distortions. These elements are arranged in groups, and make up the “formula” of a lens. These formulas are frequently licensed to third parties, who then manufacture the lens to the original specifications.

The focal length of a lens determines its angle of view, or how much of the scene in front of the camera is captured in terms of width and height. Different focal lengths capture different perspectives, which varies depending on the “format” or dimensions of the captured image when measured diagonally. For example, a 35mm frame has a diagonal measurement of 43mm, and so a lens of this same focal length would be considered “normal” in this format.

Interchangeable Lenses
More sophisticated cameras, such as DSLRs, Mirrorless EVILs and Rangefinders have lenses which can be removed and replaced with lenses of other designs and focal lengths to extend their capabilities. Some of the different lens types are:

Prime lenses are multi-element lenses with only a single focal length. They are relatively faster, lighter in weight, and more compact than zoom lenses.

Zoom lenses are multi-element lenses with a continuously variable focal length within a preset range. They are somewhat slower, heavier and larger than prime lenses, although more convenient. However, because they can take the place of several prime lenses, overall they may conserve space and weight. Technology has advanced lens design such that today’s zoom lenses may produce better quality images than yesterday’s prime lenses. However, individually, prime lenses still have a size and weight advantage.

Normal lenses attempt to capture the natural perspective of an image as seen by a human observer. In the full-frame 35mm format, a lens with a focal length of 43mm would be considered normal. However in the early days of photography, 50mm had become the accepted standard due to the higher degree of sharpness of longer lenses. Today, lenses within a range of about 40mm to 60mm are considered normal.

Wide angle or “shorter” lenses capture a wider than normal angle of view, allowing more of the scene to be captured, or allowing the photographer to shoot in more confined spaces. They have a large depth of field, making them easy to focus. Because they tend not to amplify camera movement, they can be used with slower shutter speeds or smaller apertures. In the 35mm format, lenses within a range of about 28mm to 40mm are considered wide angle. 

Telephoto or “longer” lenses capture a narrower than normal angle of view, allowing objects which are far away to be captured as if they were closer, or to permit more space between the photographer and the subject. Because they tend to amplify the camera’s movement, they are generally used with faster shutter speeds and larger apertures. Telephoto lenses benefit most from “vibration reduction” or “image stabilization”. In the 35mm format, lenses within a range of about 100mm to 300mm are considered telephoto.

Super wide-angle lenses are used to immerse the viewer in the subject or give a sense of vast space. They have enormous depth of field and so are very easy to focus. In the 35mm format, lenses within a range of about 16mm to 24mm are considered super wide-angle.

Super telephotos lenses are used to capture intricate details of distant objects and to create intimate, covert images. They have extremely narrow depth of field and are difficult to focus and to hold steady. Therefore, they are often used with tripods. In the 35mm format, lenses within a range of about 300mm to 600mm are considered super telephoto.

Fisheye lenses are ultra wide angle lenses which generally provide a 180° angle of view, but do so with a distorted (non-rectilinear) projection. They require almost no focusing. Fisheye lenses come in two varieties. Circular fisheyes project a circular image on the negative or sensor, surrounded by black. If pointed upward, you would see a 360° view of the entire horizon around the outside of the circle. Full frame fisheyes crop the image in such a way that the diagonal measurement of the frame constitutes a 180° angle of view. Fisheye lenses can be used to create fun, humorous snapshots, or photos which possess an unusual, intriguing perspective. In the 35mm format, lenses in the range of 16mm are considered super telephoto.

Catadioptric lenses are a special type of super telephoto lens which employs two mirrors in place of refractive lenses to extend the light path, resulting in a shorter physical length. This also has the affect of reducing the number and weight of glass elements. They are smaller, lighter and less expensive than fully refractive telephoto lenses of the same focal length, and have almost no chromatic aberration. However, they produce a distinct, donut-shaped bokeh, are relatively slow, are difficult to focus and have poor contrast and saturation. With a little practice however, they can produce compelling images, not unlike the other extreme, fisheye lenses. Catadioptric lenses are generally available in the range of 500mm to 800mm and have a single, fixed aperture.

Macro lenses are a special type of normal to medium-telephoto lens which possesses closer focusing capability, but retains infinity focus. This allows the image to be magnified to a greater extent than with a standard lens. In many cases, a macro lens can also substitute for a standard lens. However, if infinity focus is not required, any lens can be converted to a macro lens by reversing it or fitting extension rings (short focal length), or close-up lenses (long focal length) to it. 

Perspective Control lenses are a special type of wide to moderately long lens which allow similar “movements” to view cameras. This allow you to shift and/or tilt the lens to increase depth of field without stopping down or to correct perspective distortion created by photographing a large object, such as a building, from a less than ideal vantage point.

Lens Focal Lengths
Which length and type of lens you select depends on the type of imagery you are planning to capture.

24-35mm — architecture, landscapes, photojournalism.

35-75mm — general purpose

75-200mm — portraits

200-1200mm — nature, wildlife, sports

Lens Mounts
There are many different types of lens mounts between brands of camera. Each has its own mechanical properties and “flange focal distance” (the distance between the outermost surface of the lens mount and the film/sensor plane) requirements. Some lenses can be easily adapted to other bodies, while other are more difficult. Lenses with shorter flange focal requirements cannot be used with bodies that have  longer flange focal requirements unless additional optics are employed. This makes them similar to a teleconverter in that light loss and additional aberrations are introduced. Camera/lens combinations that do not require optical elements yield considerably better results. Lens conversions are generally for manual shooting only; aperture coupling and auto focusing are not supported.

This table shows the flange focal distance for popular lens mounts:

Mount	Flange Focal Distance	Year Introduced
Canon EF	44.00 mm	1987
Canon EF-S	44.00 mm	2003
Canon FD	42.00 mm	1971
Canon FL	42.00 mm	1964
Contax/Zeiss M42 Screw (42 x 1mm)	28.8 mm	1949
Contax C/Y	45.50 mm	1975
Contax G	29.00 mm	1994
Fujica X	43.50 mm	1980
Konica AR	40.70 mm	1965
Leica M	27.80 mm	1955
Leica R	47.00 mm	1964
Leica M39 Screw (39 x .977mm)	28.80 mm	1930
Minolta SR	43.50 mm	1958
Minolta/Sony A	44.50 mm	1985
Sony E	18 mm	2010
Nikon F	46.50 mm	1959
Olympus OM	46.00 mm	1972
Olympus Four Thirds	38.67 mm	2003
Olympus/Panasonic Micro Four Thirds	20 mm	2008
Pentax M42 (42 x 1mm)	45.46 mm	1952
Pentax K	45.46 mm	1975
Pentax Q	9.2 mm	2011
Samsung NX	25.50 mm	2010
Sigma SA	44.00 mm	1992
Soviet M39 Screw (39 x 1mm)	45.2	1930
Tamron T2 Screw (42 x .75mm)	55.00 mm	1957

Freelensing
A technique that has gain popularity amongst the “Lo-Fi” or “Toy Camera” movement is called freelensing. This is the practice of removing the lens from an interchangeable lens camera and shooting through a lens of a different mount type by simply holding the lens in front of the camera mount. This introduces light leaks and tilt-shift characteristics which can add a creative flare to the photograph.

Lens Characteristics
Lenses can exhibit certain characteristics in different combinations and proportions, making each one unique. A lens which is very sharp, but has a high degree of chromatic aberration may not look much better than a softer lens with little or no chromatic aberration.

Bokeh is the appearance of the out-of-focus areas, that is, the area beyond the plane of sharp focus. It is more easily achievable with lenses of medium to long focal length, as they naturally possess a narrower depth of field. A smoother bokeh is said to be more appealing as it is less distracting when used to separate the subject from the background or forground. Catadioptric lenses have the most distracting bokeh, the highlights being composed of tiny rings rather than solid disks.

Chromatic aberration is the color fringing that appears along the boundaries of light and dark areas within the image and is corrected by combining elements with different dispersion characteristics. Axial CA occurs across the entire image plane and can be reduced by stopping down. Transverse CA occurs toward the outside of the image, and is unaffected by stopping down. However, transverse CA is relatively easy to correct during post-processing.

Coma manifests itself as a v-shaped or comet-like flare in the image, and is corrected by using multiple lens elements.

Spherical aberration results in a softening or blurring of the image due to light rays not all converging on the same spot. It can be minimized through the use of aspherical lens elements. Lenses bearing the word “Aspherical” or “ASPH” in their designation contain these elements which greatly reduce spherical aberration.

Most of the lenses available today are autofocus, which simply means that the camera senses the sharpness of the image and rotates the focus ring for you to bring the image into sharp focus. It does not however know exactly what you wish to focus on, so a sophisticated zone system is employed to allow you some control in this area. Autofocus is always a compromise, because although it’s faster than a human, it’s not ultimately as accurate.

Many manual focus lenses are available for autofocus interchangeable-lens SLR systems, and they are greatly improved by the autofocus sensor which still tells you when the image is in focus, even though the camera is not controlling the lens. Most systems allow you to focus autofocus lenses manually, but their operation is nowhere near as smooth and precise as a dedicated manual-focus lens.