Abstract: The Canon EOS system

Photography - Canon EOS, digital, nature


Targeted towards professional and advanced amateur users, the 540EZ replaced the current Speedlite 430EZ as Canon's most sophisticated clip-on type flash unit. Main features include:

  • Full EOS system compatibility
  • Warmer color balance and improved flash exposure control reliability
  • Higher flash output (Maximum Guide Number: 54/177, ISO 100 m/ft.)
  • Extended auto-zoom coverage for focal lengths from 24mm to 105mm
  • Built-in wide panel for focal lengths as wide as 18mm
  • Exposure confirmation in A-TTL and TTL automatic flash control modes
  • Three-zone flash metering for EOS cameras with multi-point AF systems
  • Built-in AF auxiliary lamp compatible with 5-point AF when used with EOS-1N and EOS-1N RS
  • Manual flash control at 8 output levels from full power to 1/128
  • Improved stroboscopic flash operation up to 100 Hz (flashes per second)
  • Enhanced tilting capability from -7~ for close-ups to 90~ for bounce flash
  • Defeatable Save Energy (SE) function for superior operability


The Speedlite 540EZ is compatible with all EOS cameras. Moreover, any EF lens can be used as long as the flash coverage angle is sufficient. When used with an EOS that has multiple focusing points, (such as the newly introduced EOS-1N and EOS-1N RS, as well as the EOS A2 and A2E and the EOS Rebel X and XS ), the 540EZ automatically weights its flash exposure in the area of the active focusing point using the camera's multi~zone flash metering system. This results in outstanding exposure accuracy with off-center subjects, and frees the photographer to concentrate on optimum composition. It also makes the 540EZ especially valuable for capturing peak moments in flash photography of people and other moving subjects. In other areas of performance, the 540EZ features improvements in flash exposure control at all shooting distances, as well as slightly warmer color balance than previous EOS Speedlites for more pleasing color reproduction of skin tones.


The 540EZ has a maximum guide number of 54/177 (ISO 100, m/ft.), compared to 43/141 for the previous 430EZ. This powerful light output makes the 540EZ suitable for virtually any shooting situation. Benefits of the increased power include faster recycling at short to intermediate range as well as extended range for fill-in flash and long distance flash photos. Alternatively, the extra power can be used to increase depth of field for close-up work through the use of smaller apertures.


The 540EZ features an internal motorized zoom mechanism for automatic adjustment of flash coverage angle in 7 steps from 24mm to 105mm. The zoom mechanism can also be set manually at 24mm, 28mm, 35mm, 50mm, 70mm, 80mm and 105mm settings. The extended range provides full coverage for popular zoom lenses such as the EF28-105mm f/3.5-4.5 USM.

A built-in wide panel can be used to increase flash coverage for lenses with focal lengths as short as 18mm. Ideal for use with Canon's popular EF20-35mm zoom lenses, the wide panel also diffuses the flash illumination for a pleasing effect. In addition, the wide panel can be positioned perpendicular to the flash head. This setting improves the lighting quality of bounce flash portraiture by adding some sparkle, or catchlight to the subject's eyes.


When used with an EOS camera, the 540EZ is capable of everything from simple, automated flash shooting to advanced techniques such as flash exposure compensation, automatic flash control based on user-selected shutter speed and/or aperture settings, manual firing with eight selectable output levels, and intricate multiple-flash lighting setups using EOS multi-flash accessories.


A-TTL stands for Advanced Through the Lens automatic flash control. When used with an EOS camera set to Program AE or Full Auto mode, the camera and 540EZ work together to automatically set the appropriate aperture and shutter speed for proper flash exposure for indoor and low-light scenes as well as backlit subjects in daylight. This setting makes fine quality flash photography easy for anyone in any situation.


TTL automatic flash shooting is possible in other shooting modes such as aperture-priority AE, shutter~priority AE or manual exposure mode. These modes allow the photographer to select aperture, shutter speed or both settings simultaneously while flash exposure is automatically controlled.


In A-TTL and TTL modes, the 540EZ provides a flash exposure confirmation signal using a green lamp that lights for 2 seconds after the picture is taken to indicate that the flash exposure was correct. This feature is particularly useful during bounce flash photography.


The 540EZ features a built-in flash exposure compensation function which allows the photographer to adjust flash illumination independently from existing light exposure with all current EOS cameras when coupled directly to the camera's hot shoe or connected by Off-Camera Shoe Cord 1 or 2. The level of compensation can be set in 1/3~stop increments up to ~3 stops. Compensation settings on the 540EZ have priority over the camera's flash exposure compensation settings.


When desired, 540EZ flash output can be manually controlled at any of eight individual power settings from full power down to 1/128. The 540EZ's large, illuminated LCD panel shows all settings clearly, including a distance reading that's automatically calculated based on power setting, film speed, focal length and aperture in use. This feature allows the photographer to adjust camera settings or flash-to-subject distance depending on the desired result.


For interesting lighting effects, the Speedlite 540EZ can be fired at rates from 1 to 100 Hz (flashes per second) in its stroboscopic flash mode. This feature comes in handy when trying to record a range of movement, such as a golf swing or tennis stroke. It's also a lot of fun for offbeat, creative flash photos. In addition to the firing rate, users can select the total number of flashes from 1 to 100, as well as manual flash control settings down to 1/128 power.

Additional 540EZ features include:

* BOUNCE FLASH: The flash head can be angled upward or to the right or left for bouncing the flash off of nearby surfaces such as a ceiling or wall to create a softer lighting effect. The flash head can also be angled 7~ downward to provide full flash coverage for close-up shots.

* AF AUXILIARY LIGHT CORRESPONDING TO FIVE FOCUSING POINTS: The built-in AF auxiliary light automatically fires in low light and low-contrast situations to aid the camera's autofocusing system. When combined with the EOS-1N or EOS-1N RS, the AF auxiliary light emission automatically corresponds to the camera's five autofocusing points. The effective distance range for the central focusing point is 0.5~15m/1.6~50 ft.

* FLASH SYNC TIMING: The sync timing can be set to either first-curtain sync, which fires the flash as soon as the shutter is fully opened, or second-curtain sync, which fires the flash immediately before the shutter closes.

* SE (SAVE ENERGY) FUNCTION: When the flash is set to SE mode, the power automatically turns off after 90 seconds of non-operation in order to conserve battery power. A 3-position main switch allows full-time operation as well, ideal for remote operation.

* MODE MEMORY: All flash settings are automatically memorized when power is shut off, and are even retained for up to 90 seconds while changing batteries.

* RETRACTABLE SHOE LOCK: A spring-loaded locking pin on the accessory shoe ensures a secure fitting to EOS cameras equipped with a matching socket.


The body of the 540EZ has been designed to meet the following objectives:

* RELIABILITY: Speedlite 540EZ is constructed to the highest standards of reliability and quality to meet the needs of demanding professional photographers who use electronic flash regularly.

* OPERABILITY: Control buttons are large for ease of use but recessed to prevent inadvertent operation. A 2~step procedure allows users to select and lock in critical settings such as flash exposure compensation.

* DISPLAY PANEL READABILITY: The size of the LCD panel is 2.3 times larger than that of the 430EZ, with priority placed on improving overall readability. A built-in illuminator is available at the touch of a button for easy visibility under any shooting conditions.


Speedlite 540EZ runs on 4 AA-size batteries. Users can freely select alkaline, rechargeable Ni-Cd or the new AA~size lithium cells. The 540EZ is also fully compatible with dedicated external power supplies such as Canon's popular Compact Battery Pack E and Transistor Pack E, which are already on the market for use with Speedlites 480EG and 430EZ. Their additional power extends the versatility of the 540EZ for professional flash photography by reducing recycling time between flashes and increasing overall shooting capacity.


Canon's line of dedicated flash accessories for Speedlite 540EZ includes Off-Camera Shoe Cord 2 for separating the flash from the camera, as well as adapters and cords for configuring elaborate multiple flash set-ups. Even when using more than one flash, exposure can be controlled automatically by the EOS TTL system.