I took a flash photo and the background is pitch black or very dark
This is the flip side of question 7. In P program mode and all flash-using PIC icon modes except for night mode if your camera has it the camera uses the flash as the primary light source for the foreground subject. If the ambient light levels are low, therefore, the background will turn out very dark. This is because the flash is not illuminating the background and the shutter speed is too short to expose adequately for background areas. Remember that the light from any battery-powered flash...
Modelling flash
Large studio flash units frequently have incandescent tungsten bulbs built in alongside the main flash tube or tubes. These constant-light bulbs cast light on the subject in much the same way as the actual flash bulb would. This constant light is known as a modelling light, as it allows you to preview the flash effect in a rough fashion - or at least see where the flash shadows and reflections are likely to fall. The Canon modelling flash feature lets you simulate the effect of the flash going...
General flash photography tips
Remove any lens hoods when using an internal flash. If you don't you'll probably notice a dark crescent-shaped flash shadow at the bottom of your photos. Don't stand closer than a metre or so 3 feet to your subject unless you have a macro flash. You'll get similar shadowing at the bottom of the photo. An external unit with a small diffuser can help, though. If the tilt swivel head is not set straight on, double-check its position if you switch from landscape to portrait orientation or...
ATTL advanced TTL
Canon's first step in altering flash exposure design was the creation of A-TTL, or advanced through the lens flash metering, which was introduced with the T90 camera and continued on to the EOS series of film cameras. A-TTL flash units 300TL and EZ series Speedlites only send out a brief burst of light during the metering phase. ie when the shutter release button is pressed halfway This preflash is recorded by an external sensor on the front of the flash and used to determine a reasonable...
Using wireless ETTL
You can specify one of four different data channels for flash control, and each flash unit can be put into one of three groups. The four channels are there so that up to four cameras can use wireless E-TTL in the same physical location without conflicting with each other, and the three groups are there so that independent flash output ratios can be specified though only with certain cameras see below . When wireless mode is used with any type A body you have full E-TTL metering, FP mode, FEL...
Save Energy SE mode
Most EOS flashes go into low-power or SE mode called Energy Conservation Control in some Canon material after a predetermined period of time - usually 90 seconds or 5 minutes - in order to minimize battery drain. Some flash units are always in SE mode when powered on. However, since it can be annoying to have your flash unit turn itself off in the middle of setting up a shot some flash units have a three-position switch - off, on and SE. The ability to override SE mode is very important for...
Av aperture priority mode flash
Av mode lets you set the depth of field by specifying the lens aperture. The camera then chooses a shutter speed ranging from 30 seconds to the camera's X-sync speed, in order to expose the background correctly. If that means the shutter speed is some really low value so that you need to use a tripod to avoid camera-shake blur, so be it. In dark conditions, therefore, Av mode works in slow sync mode. Flash duration flash output is determined by the flash metering system. Like Tv mode the camera...
Flash metering principles
Flash metering has very different requirements from normal ambient light metering for the reasons outlined above. Ambient light metering is performed well in advance of the shutter opening. EOS cameras, for example, activate the internal light meter when you press the shutter release button down halfway. But the subject-illuminating flash pulse, however, occurs after you press the shutter release all the way. That means that the flash pulse appears after the mirror has flipped up blocking the...
Fill flash ratios
The fill flash ratio is commonly described in terms of the ratio of ambient light plus fill flash combined, compared to the fill flash alone. Canon EOS gear, however, usually lets you adjust the fill flash in terms of stops of flash output, in either 1 2 or 1 3 stop increments. What's the relationship between the two ways of describing fill flash A ratio of 1 1 would mean that the flash unit is the sole source of light 0 ambient 1 flash and therefore you wouldn't have a fill flash situation. A...
Setting stroboscopic flash
High-end Canon hotshoe flash units have a stroboscopic mode, activated by pressing the mode button until MULTI is displayed on the rear LCD panel. You can then enter the firing frequency in hertz ie the number of flashes per second and the power output setting. The 5xx flashes also let you specify the actual number of stroboscopic light flashes as well. The 4xx flashes don't, so you have to calculate that number from the time period the shutter is kept open and the number of flashes per second...
Existing documentation
Learning more about flash photography with EOS cameras is hard as there's relatively limited information available on the topic. Canon's manuals tend to be fairly short, and not much information has been published about the flash algorithms used by EOS cameras. There's a brochure on the topic - Canon's Flash Work, but unlike the excellent and similarly titled book Lens Work, the flash brochure does not go into much detail. Hove Silver Pixel Press published a book on the Canon Speedlite 540EZ...
Handlemount grip flash
Canon still make one large flash unit of this type, the 480EG. It's basically a flash bracket with a massive heavy-duty flash attached to the side. The camera sits on the bracket and is held in place via the tripod mount. This type of handle flash is sometimes jokingly referred to as a potato masher flash unit. The 480EG is a high-output flash unit meant for press or wedding photographers, but hasn't been updated in some time and is a TTL-only flash no A-TTL or E-TTL support . Nowadays people...
Rapidfire mode
Electronic flashes work by charging up a capacitor with electricity, then releasing the stored-up power in a split-second burst of light. This charging process, the recycle time, takes up to a few seconds on larger units - which can be a problem if you need to take several flash photos in fairly rapid succession, such as at a wedding. Many EOS flashes have the ability to be triggered even if not fully recharged, on the theory that there are times when you're better off being able to take a...
What about third party units
A number of companies other than Canon sell EOS-compatible flash units. The vast majority, however, are TTL only. There is also a small risk of compatibility problems with both current and future EOS camera bodies. If you're satisfied with TTL operation particularly if you have a type B camera with no plans to upgrade to a type A and you've tested the flash unit to ensure that it works with your existing camera body, then an inexpensive third party unit may be the way to go if you're on a tight...
Bounce flash swivel and tilt
Many of Canon's external flash units have the ability either to tilt or both tilt and swivel the flash head independently of the flash body. The 430EZ, for example, lets you tilt the head from 0 straight on to 90 . Left swivel goes from 0 to 180 -facing backwards Right swivel only goes from 0 to 90 . There are click stops at various detent positions, and a spring-loaded bounce latch keeps the flash head pointed head-on. Tilt and swivel let you bounce reflect the flash unit's light off walls,...
Cameras
Cameras with fixed 35mm internal flash coverage, GN 12 EOS 750 first EOS camera to sport a built-in flash , 700, 10 10s, Rebel S 1000F, EOS 5000 888. Cameras with fixed 35mm internal flash coverage, GN 14 EOS Rebel II S 1000FN . Cameras with fixed 28mm internal flash coverage, GN 12 Rebel X EOS 500 Kiss, Rebel 2000 EOS 300 Kiss III, EOS Kiss III L, EOS 300V Rebel Ti Kiss 5, Rebel G EOS 500N New Kiss, EOS 3000 88, 3000N 66. Cameras with fixed 28mm internal flash coverage, GN 13 EOS Elan II E 50...
TTL and ATTL flash metering patterns
The flash metering pattern is determined by the type of flash sensors built into the camera. If the camera has only one focussing point then it will have a single zone flash sensor. Flash metering is conducted using this sensor in a centre-weighted averaging pattern. If the camera has multiple focussing points then it will have multiple zones what Canon call their AIM system. The number of flash metering zones depends on the camera model. For instance, the EOS 10 10s has three focussing points...
Trigger circuit voltage
Old flash units - both studio and hotshoe-mount - used pretty high voltages between the camera and the flash - often from 25 to 250 volts. This is because the flash units were fired by simple switches - electrical contacts. Modern cameras, however, rely on electronic circuitry rather than electric switches. This allows for more flexibility and the possibility for computerization, but the circuits can't withstand high trigger circuit voltages anything above 6 volts, in the case of EOS cameras,...
Auto fill reduction
Also called automatic reduction of flash output in some Canon documentation. Canon EOS cameras automatically use regular flash exposure with no compensation when ambient light levels are low - 10 EV or lower. However, when ambient light levels are brighter - 13 EV or higher - the camera will switch to fill flash mode and reduce the flash unit's output level. It does so in TTL mode by dropping flash output by 1.5 stops. Between 10 and 13 EV the camera will smoothly lower the flash unit's output...
AF assist light
It's very hard for cameras based on passive autofocus mechanisms this includes all EOS cameras except the manual-focus EF-M to focus when it's dark, since they rely on contrast between light and dark areas. For this reason many EOS cameras have a built-in light that automatically illuminates in low light situations to help the autofocus system to work. On many of these cameras this is a relatively discreet patterned red light from a bright red LED light emitting diode , but on some it's an...
Manual flash triggering for light painting
A fun way of taking interesting photos in the dark is to trigger a flash unit manually whilst leaving the shutter open - sometimes called open flash. For example, you could set your camera on a tripod, open the shutter by putting the camera into bulb mode, and then walk around the scene with a flash unit, painting the scene with light. Coloured gels can be taped over the flash head as well, to illuminate the photo with different colours of light. Canon Speedlites with manual controls or old...
How wireless ETTL works
Canon's wireless E-TTL system employs brief digitally-encoded pulses of light either visible or infrared, depending on the master unit used to transmit commands from a master flash unit to a slave unit or multiple slaves. It doesn't use radio signals like most third party systems, so you can't trigger flashes remotely from great distances, such as the other side of a sports arena. But it's ideal for quick, portable and flexible flash setups in smaller spaces. Canon chose light-controlled...
Enabling second curtain sync
This depends very much on the camera and flash unit that you're using. Early on, Canon put control for this feature on the flash unit. Later they switched to putting control for this feature on the camera body. So whether you have second-curtain sync available to you depends on a complicated set of permutations. Many mid to high end Canon flash units, listed below, have a button or switch which lets you enable second curtain sync. It's usually marked with a triple triangle gt gt gt symbol or...
Flash exposure lock FEL
EOS cameras type A which support E-TTL also support flash exposure lock when used with EX flash units. This feature lets you lock flash settings in, then optionally recompose the image before taking the final photo. This allows you to adjust the flash settings in certain difficult to meter cases. Canon first introduced FEL in 1986 with their T90 camera and 300TL flash, but dropped the feature with the first EOS cameras. It wasn't until 1995, with the introduction of the Elan II E 50 55 and...
Do not focus and recompose
The fact that the camera biases flash exposure to the nearest focus point, if the camera has multiple focus points, is important to keep in mind. If you're in the habit of using the old focus, lock AE and recompose image technique, be sure not do this when taking flash photos. Flash metering occurs after ambient light metering, so in this case you're locking AE but not flash metering, and therefore recomposing messes up your flash metering. Instead, select the focus point that's closest to your...
Exposure value EV
The sensitivity of camera gear at autofocussing or determining correct exposure metering is rated in terms of EV - exposure value - for a given lens type and film speed. Since the amount of light hitting the surface of film is determined by exposure time shutter speed and lens aperture, exposure values are simply combinations of shutter speeds and apertures. For example, f4 at 1 30 sec has an EV of 9, which is the same EV as f2 at 1 125. Toomas Tamm has a complete EV table on his Web site. Both...
Sigma
Sigma, Japanese maker of many third-party lenses, build four flash units compatible with Canon EOS. Two are TTL - the EF-430 ST and the EF-500 ST, and two are E-TTL - the EF 430 Super and the EF-500 Super. Some of these flash units are listed on Photozone. The EF-500 Super is particularly well regarded by a lot of EOS users, since feature-wise it's nearly identical to Canon's 550EX, which costs twice as much. The Sigma flash is not built as sturdily as the Canon, but it's hard to argue with the...
Which bodiesflashes have FEC
Flash exposure compensation may or may not be available to you, depending on which camera body and flash you have. Most midrange EOS cameras support FEC for internal flashes, but most low-end EOS cameras do not. Also, remember that FEC will not work in the basic PIC metering modes - just P, Tv, Av and M modes. For FEC to work with an external flash you need one of the following two cases either both a camera capable of supporting FEC on external flash units and a flash unit capable of receiving...
Disabling ETTL
There are times when TTL metering may be more desirable than E-TTL. A common example is a studio setting where analogue optical slave units can be fooled by the E-TTL preflash. The 550EX, MR-14EX and MT-24EX let you disable E-TTL via a custom function, but they're the only ones. All other EX flash units will always operate in E-TTL mode when mounted to an E-TTL-capable camera, even if the camera is also capable of supporting TTL. One way around this is to buy Canon's Hot Shoe Adapter for wired...
The Off Camera Shoe Cord
The OCSC 2 is a simple coiled cord with sockets on either end that lets you attach a flash unit to your camera's hotshoe and move the flash independently of the camera, up to a distance of about 60 cm 2 feet . This cord, though expensive, preserves all flash functions including E-TTL if it's available, and is useful for mounting a Speedlite flash to a flash bracket. It's pretty short, however. You can connect two of them together if you need more distance, but Canon do not recommend this...
Flash exposure compensation FEC
There are times when you may want to adjust the total flash output from a flash unit above or below what the assumed mid-tones that the camera thinks you probably want. For example, a scene that's mainly white or mainly dark will fool automated sensors, so you may want to override the flash unit. This is flash exposure compensation referred to as fill-in ratio control or flash level control in older Canon material. As noted in the section on fill flash, a common application for flash is...
German Flash Canon
Metz, a respected German maker of flash units, sell quite a few Mecablitz flashes that work with EOS cameras by means of an adapter system. Photozone list some of them - the 54MZ-3, 50MZ-5, 40MZ-3, 40MZ-1, 40MZ-3i, 40MZ-1i, 40MZ-2, 40AF-4 and 32MZ-3 - and describe their features. The Metz range is, in fact, much more extensive than Canon's, and Metz offers features that Canon do not - such as flash units with memory settings, built-in secondary reflectors, clip-on coloured filters and audio...
List of which bodiesflashes have FEC
Camera bodies which do not support any kind of FEC even with flash units with external FEC controls Camera bodies which only support FEC when used with an external Speedlite flash unit which has FEC controls EOS 600 630, RT, 700, 1, 10 10s, all EOS 1000 series cameras, all EOS Rebel series cameras, all EOS Kiss series cameras, 300, 300V, 500, 500N, 5000 888, 3000 88, 3000N, IX Lite IX 50 IX 7. Camera body which supports FEC on the internal flash but not on external flash units unless they have...