Canon EOS flash system
Encyclopedia
Canon Inc.
is a Japanese multinational corporation that specialises in the manufacture of imaging and optical products, including cameras, camcorders, photocopiers, steppers and computer printers. Its headquarters are located in Ōta, Tokyo, Japan.-Origins:...
's EOS flash system refers to the photographic flash mechanism used on Canon's film
Photographic film
Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variable crystal sizes that determine the sensitivity, contrast and resolution of the film...
(35mm
35 mm film
35 mm film is the film gauge most commonly used for chemical still photography and motion pictures. The name of the gauge refers to the width of the photographic film, which consists of strips 35 millimeters in width...
and APS
Advanced Photo System
Advanced Photo System is a film format for still photography first produced in 1996. It was marketed by Eastman Kodak under the brand name Advantix, by FujiFilm under the name Nexia, by AgfaPhoto under the name Futura and by Konica as Centuria.- Design :The film is 24 mm wide, and has three...
) or digital
Digital camera
A digital camera is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. It is the main device used in the field of digital photography...
EOS
Canon EOS
The Canon EOS autofocus 35 mm film and digital SLR camera system was introduced in 1987 with the Canon EOS 650 and is still in production as Canon's current DSLR system...
single-lens reflex camera
Single-lens reflex camera
A single-lens reflex camera is a camera that typically uses a semi-automatic moving mirror system that permits the photographer to see exactly what will be captured by the film or digital imaging system, as opposed to pre-SLR cameras where the view through the viewfinder could be significantly...
s. The line was first introduced in 1987. It has gone through a number of revisions over the years, as new flash exposure metering systems have been introduced. The main light-metering technologies are known as A-TTL, E-TTL, and E-TTL II.
The EOS flash system is capable of wireless multiple flash control, whereby a master flash unit or IR transmitter (ST-E2) mounted on the camera body can control up to 3 groups of flash units. The Canon EOS 7D
Canon EOS 7D
The Canon EOS 7D is an 18.0 effective megapixel APS-C crop CMOS digital single-lens reflex camera made by Canon. It was announced on September 1, 2009...
is the first camera body to be able to control Speedlites wirelessly without the use of a Master Speedlite or IR transmitter; two other current EOS models, the 60D
Canon EOS 60D
The Canon EOS 60D is a digital single-lens reflex camera from Canon. It is part of the Canon EOS line of cameras and succeeds the EOS 50D. It was publicly announced on August 26, 2010....
and 600D/Rebel T3i
Canon EOS 600D
The Canon EOS 600D is an 18.0 megapixel digital single-lens reflex camera, released by Canon on February 7, 2011. It is known as the EOS Kiss X5 in Japan and the EOS Rebel T3i in the United States and Canada...
, also have wireless flash capabilities.
Metering systems
Canon has introduced several different metering systems for its flash products: A-TTL, E-TTL, and E-TTL II. Each system represents different approaches to achieving the proper flash exposure.A-TTL
A-TTL is an initialism that stands for Advanced-Through The Lens flash metering. As with ordinary TTLThrough-the-lens
Through-the-lens metering is a photographic term describing a feature of cameras capable of measuring light levels in a scene through their taking lenses, as opposed to a separate metering window...
flash exposure systems, a sensor inside the camera reads the amount of light being reflected off the film during the exposure. When the sensor determines that the exposure is sufficient, it terminates the flash pulse. A-TTL, first seen on the T90
Canon T90
The Canon T90, introduced in 1986, was the top of the line in Canon's T series of 35 mm Single-lens reflex cameras. It was the last professional-level manual-focus camera from Canon, and the last professional camera to use the Canon FD lens mount...
(which predates the EOS family), is a flash exposure system that adds a brief preflash during exposure metering when the camera is in the programmed exposure (P) mode. The amount of light returned from this preflash is used to determine an appropriate tradeoff between aperture and shutter speed in P mode. Depending on the specific flash unit and whether or not it is set to bounce, the preflash might be infrared or it might be the normal white flash. In an A-TTL system the sensor that reads the preflash return is located on the flash unit; this caused some issues especially when using filters as the filter would cover the lens (but not the sensor outside the lens) thus causing inaccurate settings. Some early Canon EOS cameras also used the A-TTL preflash in non-programmed exposure modes to detect "out of range" conditions; the "out of range" warning feature was dropped on later models, reportedly due to patent conflicts.
E-TTL
E-TTL (Evaluative-Through The Lens) is a Canon EOS flash exposure system that uses a brief pre-flash before the main flash in order to obtain a more correct exposure. Unlike TTL and A-TTL metering, which use a dedicated flash metering sensor mounted in the base of the mirror box, E-TTL uses the same evaluative metering sensor used for ambient metering. Like TTL (and like the actual flash metering, but not the pre-flash, of A-TTL), the sensor is internal to the camera and takes its exposure via the lens so any filters added to the lens will also affect the E-TTL readings giving more accurate exposure information to the camera.The pre-flash occurs immediately before the main flash (except when using the camera / flash in 2nd curtain synch mode) and is barely perceptible, although can be seen if you watch carefully for it. The pre-flash may cause undesirable reactions of animate objects. E.g., humans may blink as a reaction to the pre-flash, and have their eyes closed by the time the main flash occurs. When using flash exposure lock (FEL), the pre-flash is fired when FEL is activated.
E-TTL II
E-TTL II is basically a software improvement on E-TTL and is now a standard in all EOS cameras introduced with or after the Canon EOS-1D Mark IICanon EOS-1D Mark II
The EOS 1D Mark II is a professional 8.2 megapixel digital single lens reflex camera camera body produced by Canon. The EOS 1D Mark II is the successor of the EOS 1D.-Features:The EOS 1D Mark II features:* 28.7 × 19.1 mm CMOS sensor...
in 2004. E-TTL II is implemented in the body, not the flash unit, and therefore can use existing E-TTL flash units and EF lenses.
The main improvement of E-TTL II is that it gives a more natural flash exposure, by being able to handle tricky scenes where normally the old E-TTL system will be thrown off. Such improvements are possible because E-TTL II now incorporates lens-to-subject distance information in its calculation (where available) to assist in determining an approximate guide number
Guide number
The guide number for an electronic flash measures its ability to illuminate the subject to be photographed at a specific film or sensor sensitivity and angle of view...
for flash output. The flash metering system is also no longer linked to the AF system, where in the old E-TTL metering bias is given to the selected AF point. Rather, E-TTL II compares the ambient and the pre-flash light levels of the scene to determine where the subject lies, in conjunction with subject distance information if available. This gives the photographer flexibility to lock focus and recompose the scene without fooling the flash metering system. 'Hotspots' (areas of high reflectance) that will normally throw off the flash metering system are also ignored in the calculation.
Speedlite products
Speedlite is the trade nameTrade name
A trade name, also known as a trading name or a business name, is the name which a business trades under for commercial purposes, although its registered, legal name, used for contracts and other formal situations, may be another....
for Canon's line of external flashes
Flash (photography)
A flash is a device used in photography producing a flash of artificial light at a color temperature of about 5500 K to help illuminate a scene. A major purpose of a flash is to illuminate a dark scene. Other uses are capturing quickly moving objects or changing the quality of light...
for use with their EOS line of cameras
Canon EOS
The Canon EOS autofocus 35 mm film and digital SLR camera system was introduced in 1987 with the Canon EOS 650 and is still in production as Canon's current DSLR system...
. It is similar but not to be confused with Nikon Corporation's "Speedlight
Speedlight
Speedlight is the brand name used by Nikon Corporation for their photographic flash units, used since the company's introduction of strobe flashes in the 1960s. Nikon's standalone Speedlights have the SB- prefix as part of their model designation...
" brand for their flashes. The Speedlite name is also used by Ricoh
Ricoh
or Ricoh, is a Japanese company that was established in 1936 on February 6th, as , a company in the RIKEN zaibatsu. Its headquarters is located in Ricoh Building in Chūō, Tokyo....
for its unrelated product line of flash units, such as the Ricoh Speedlite 202.
The brand names are intended to indicate that strobe flashes produce much shorter and more intense bursts of light than earlier photographic lighting systems, such as flashbulbs, or continuous lamps used in some studio situations.
320 EX
In 2011, Canon introduced a new flash that has a built-in LED light. One reviewer noted that the flash occupied a completely new niche in the Canon flash lineup, "slotting between the 270 EX II and the 430 EX II", and added that it did not replace a previous model.The LED can be used as a spotlight to see objects in dim light before taking a photo, but is primarily present to provide fill light for video shooting. The aforementioned reviewer also stated that the LED could be used in some situations as a substitute for a standard flashlight.
400 series flashes
Canon's external flashes with model numbers in the 400 range tend to be their midrange external flashes. They all tend to have the ability to adjust the direction of the flash via a swivel head, which allows the photographer to bounce the flash off walls, ceilings, and other objects, diffusing the light that hits the subject and reducing the harsh shadows associated with on-camera flash. The 400 series differs from the higher end 500 series mostly by lacking a remote controller.420 EX
The Speedlite 420EX is an external flash made by Canon. The Speedlite 420EX is one of Canon's older midrange flashes, being replaced by the 430EX in 2005. It was primarily intended for users wanting to step up from the entry-level flashes, as well as for use as a slave flash along with the more advanced Speedlite 550EX flash.Compared to its predecessor, the 380EX, it provided slightly more power, an improved autofocus assist beam, tilt and swivel (the 380EX could only tilt), and the ability to serve as a slave in Canon's wireless multiple-flash system. Like the 380EX, the 420EX did not provide user controls (other than enabling and disabling high-speed sync); any flash-related settings, such as exposure compensation or second-curtain synchronization, had to be set using the body.
Its autofocus assist system was designed to cover Canon's autofocus layouts with between 1 and 7 autofocus points; it was not designed to cover the 45-point autofocus layout used by higher-end bodies. It used two lamps to project horizontal and vertical patterns, which matched the line sensitivity of the autofocus sensors used in those autofocus layouts. Either or both patterns would be projected depending on the body being used and the user's selection of autofocus sensor(s).
Canon Museum:420EX
430 EX and 430 EX II
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
controller, such as Speedlite 550EX or Speedlite 580EX II.
The flash head can swivel up (to 90°), right (to 90°) and left (to 180°). The swivel properties allow the photographer to bounce the flash off walls, ceilings, and other objects, diffusing the light that hits the subject and reducing the harsh shadows associated with on-camera flash.
Both flashes support TTL, E-TTL, and E-TTL II flash metering and have Guide Number
Guide number
The guide number for an electronic flash measures its ability to illuminate the subject to be photographed at a specific film or sensor sensitivity and angle of view...
s of 141ft/43m (at ISO 100 and 105 mm).
The Speedlite 430EX II improved on its predecessor by adding a stronger, all metal foot with quick release mechanism, silent flash recycling, and 20% shorter recycle times.
500 series flashes
Canon's external flashes with model numbers in the 500 range tend to be their high end external flashes. All three products so far have included a controller that enables wireless control of other flashes. Another common feature is the ability to adjust the direction of the flash via a swivel head. The swivel properties allow the photographer to bounce the flash off walls, ceilings, and other objects, diffusing the light that hits the subject and reducing the harsh shadows associated with on-camera flash.550 EX
Canon EOS
The Canon EOS autofocus 35 mm film and digital SLR camera system was introduced in 1987 with the Canon EOS 650 and is still in production as Canon's current DSLR system...
, primarily the Canon EOS 3
Canon EOS 3
The Canon EOS-3 is a 35mm film single-lens reflex camera for professionals and advanced amateurs built by Canon of Japan. It was introduced in November 1998and was offered as recently as 2007, though is no longer....
. The 550 EX can act as a controller that enables wireless control of other flashes. Until the release of the Speedlite 580EX in late 2004, the 550EX was Canon's top-of-the-line flash.
580 EX and 580 EX II
The Speedlite 580EX and Speedlite 580EX II are flashes made by Canon for use with their EOS line of cameras. The 580 EX was succeeded by the Speedlite 580EX II in early 2008. The flashes in the 500 EX series can act as a controller that enables wireless control of other flashes. They also have a slightly stronger maximum flash output and a more durable casing.Key features of the 580 EX II that make it desirable are a built-in PC terminal, metal foot, faster recycling time and a much easier-to-use battery cover.
ST-E2 transmitter
The Speedlite Transmitter ST-E2 is a camera-mounted infraredInfrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
controller for Canon's flashes. It allows for multiple off-camera flashes to be fired in E-TTL mode without the need for connecting wires.
Flashes being triggered by the ST-E2 can be assigned to either group A or group B, and the ST-E2 can be configured to with a user-set ratio of flash output between the two groups, with ratios varying from 8:1 to 1:8 in half-stop increments.
High-speed sync is also supported by the ST-E2, but it does not support second-curtain synchronization or stroboscopic flash.
A built-in focus assist light allows the ST-E2 to be used to help a camera focus in very low light.
While the Speedlite 580EX and Speedlite 580EX II flashes use visible light for communicating with slave flashes, the ST-E2 uses near-infrared light, and has a quoted range of 10-15m indoors, and 8-10m outdoors.
The ST-E2 uses a single 2CR5 lithium battery, which is said to be good for 1500 transmissions.
Macro flash products
Canon also has some flash products for macro photographyMacro photography
Macrophotography is close-up photography, usually of very small subjects. Classically a macrophotograph is one in which the size of the subject on the negative is greater than life size. However in modern use it refers to a finished photograph of a subject at greater than life size...
, the Macro Twin Lite MT-24EX and Macro Ring Lite MR-14EX circular-shaped flashes.
Misc. accessories
Canon also sells several supporting accessories for its Speedlite products. Among these are the Off Shoe Camera Cord OC-E3, Compact Battery Pack CP-E4 (an external battery), and the Speedlite Bracket SB-E2, which allows off-axis flash.External links
- Canon Flash Work (for E-TTL II) - Official CanonCanon Inc.is a Japanese multinational corporation that specialises in the manufacture of imaging and optical products, including cameras, camcorders, photocopiers, steppers and computer printers. Its headquarters are located in Ōta, Tokyo, Japan.-Origins:...
web site with information and tutorials for the use of Speedlites with EOS SLR cameras which utilize E-TTL II. - Canon Flash Work (for E-TTL) - Older unofficial Flash Work website (hosted at ifrance.com) with tutorials for the original E-TTL implementation.