Background
Entry-level and mid-range digital SLR cameras have built-in flash units. These built-in flash units are extremely useful for normal flash photography where needed.
Nevertheless, built-in flashes have their limitations. In some situations they are not powerful enough - for example, shots of large groups or stage photos taken from the audience. When taking ordinary snapshots of people or objects, they tend to produce flat-looking photos because the flash illuminates the subject directly head-on.
Canon produces five different EOS-compatible clip-on and standalone flash units. These units give photographers choices: from more versatile normal flash photography all the way up to professional-level flash photography that responds to a wide variety of shooting conditions.
This article introduces the features and their applications of the newly released Speedlite 430EX II when used in combination with an EOS Digital camera with built-in flash.
Overview and characteristics of the 430EX II
The new Speedlite 430EX II (Photo 1) is based on the 430EX, which was released in March 2005. It is a digital-era flash unit with improved functionality, operability, and reliability. The unit's characteristics are outlined below.
(1)Maximum guide number 43
The guide number ranges from 25 to 43 (at ISO 100 in meters) corresponding to lens focal lengths from 24 to 105mm. What this means is the 430EX II can produce up to 11 times the light output of the EOS Kiss X2's built-in flash.
(2)Auto zoom adjustment for the image sensor size
The flash-coverage angle of the EOS Kiss X2 is fixed so that it always covers the angle of view of a 17mm lens. With the 430EX II, however, the system automatically recognizes the current focal length of the lens and the camera's sensor size and automatically sets the appropriate zoom angle to cover the angle of view of the shot.
(3)Built-in 14 mm wide panel
When the wide panel is in position, the flash coverage is set to match a 14-mm lens (on a camera with a 35mm full-frame sensor). Thus, the unit could cover the angle of view of an 8.75 mm ultra wide lens.
(4)Bounce adjustment
The pop-up position of built-in flashes is fixed (see Photo 2 for an example of the photo results). On the 430EX II, however, the flash head can be adjusted as shown in Figure 1, permitting a wide range of bounce flash techniques.
Bouncing the flash off the ceiling or other surfaces creates a soft, indirect light, which enables the photographer to attain very natural-looking flash photos. Photo 3 shows the benefits of the bounce flash versus Photo 2, taken with a direct head-on flash.
(5)Compatible with E-TTL II autoflash, which automatically provides natural-looking flash photos
The 430EX II uses the E-TTL II autoflash (a preflash-evaluative exposure adjustment system). E-TTL II uses a reference exposure aperture, set either automatically or manually, and in just 0.002 seconds fires a weak pre-flash just before the exposure, detects the overall light conditions in the scene with the camera's multi-segment light sensor, instantly evaluates and determines the subject's position and the shooting conditions. It then calculates and stores the necessary flash power to make a natural-looking photo. It then immediately fires the main flash.
We'll look closer at the E-TTL II's operating sequence and its relationship with the shooting modes later in this article.
(6)Built-in AF-assist beam
When using the EOS Kiss X2 alone, the camera will fire the built-in flash intermittently when needed as an AF-assist beam.
When the 430EX II is mounted, however, the built-in flash cannot be used. so the 430EX II's built-in AF-assist beam (which supports one to nine AF points) is used.
(7)Fast Recycling of only 0.1 to 3 seconds
Using a new technology developed for the 580EX II, the 430EX II's recycling times are as much as 20% shorter than the 430EX's.
(8)Silent recycling
The recycling whine has been eliminated by raising the frequency of the oscillator circuit above the threshold of human hearing (to 70 kHz) with a microprocessor frequency controller. This technology was developed for the 580EX II.
(9)Quick camera-attachment locking mechanism
The 430EX II uses a simple and reliable quick-lock and quick-release lever instead of the previous screw collar, to mount it to the camera. This system was well received on the 580EX II, and gives a dramatic improvement in handling of the unit. It also features a lock-release button to prevent the lock from accidentally releasing.
(10)Nine custom functions
The 430EX II comes with the nine custom functions listed in Table 1. The missing numbers are for custom functions found on the high-end 580EX II but not included on the 430EX II.
|
 |
Newly added functions |
(11)Camera menu for setting flash functions
When the unit is attached to an EOS-1D Mark III, EOS-1Ds Mark III, EOS 40D, or EOS Kiss X2, the user can set the flash's functions and custom functions from a camera menu (Figure 2) displayed on the camera's control panel.
 |
 |
| Figure 2: EOS Kiss X2's external flash control menu | |
(12)Improved reliability
The following improvements, based on the 580EX II, have been implemented to make the 430EX II more reliable.
· Metal mounting foot
To increase the rigidity of the mounting foot, the material was changed from plastic to metal.
· Improved communication reliability
Reliability of communications between the camera and the flash unit has been improved by optimizing the contact shape and contact pressure.
· Safety mechanism prevents flash-head overheating
With the move to digital, there are many more opportunities to fire the flash repeatedly in a short time since the number of shots one can take is virtually unlimited, unlike in the old days when you had to change film every 36 exposures.Repeatedly firing the flash, however, runs the risk of damaging the flash head and surrounding components because the flash head heats up rapidly.
The 430EX II has a safety mechanism that engages after 60 consecutive full-power flashes and forces the unit to wait eight to 20 seconds between flashes. Once the safety mechanism is engaged, it remains in effect until the flash is not fired for about 15 minutes. The unit then returns to its normal flash ready state.
(13)Continuation and improvement of the 430EX's superb functions
Table 2 compares the main specifications of the 430EX and the 430EX II.
Operating sequence and characteristics of the E-TTL II autoflash system
· Same operation, whether using the built-in flash or the 430EX II
The camera, naturally enough, takes care of all the built-in flash's automatic exposure controls. When an external flash unit is attached, the basic operations remain virtually the same on EOS cameras using E-TTL II. Thus, conceptually, the following ideas are correct.
· All that changes is that a more powerful flash replaces the built-in flash
· The pop-up signal of the built-in flash switches on the 430EX II
· E-TTL II autoflash operating sequence
Improvements were made steadily to the preflash-evaluative exposure adjustment system first developed in 1995. This evolved into today's E-TTL II autoflash system - which also includes the lens-to-subject distance - after the calculation algorithms were completely revamped in 2004.
When the shutter button is pressed halfway, the E-TTL II system immediately performs operations A to F in Figure 3.
| A | : | The EOS transmits the lens's focal length to the 430EX II (automatically sets the 430EX II's inner zoom). | |
| B | : | The EOS autofocuses. | |
| C | : | The EOS measures the ambient light (the scene's light levels) through the lens, following the set metering mode (E-TTL II automatically sets EOS-1D-series models to evaluative mode in this case). | |
| D | : | An algorithm finds the appropriate exposure using the shutter and aperture. | |
| E | ,F | : | The EOS sets the aperture and shutter speed according to the algorithm's result. These settings are made essentially in the same way as normal AE shooting with no flash, following the constraints of the shooting mode as shown in Table 3. |
|
When the shutter button is pressed down completely, the system immediately performs operations G to N.
| G | : | The multi-segment AE sensor measures the instantaneous ambient light prior to the preflash. |
| H | : | The EOS sends a preflash command to the 430EX II; the 430EX II fires the preflash (1/32nd of a full flash). |
| I | : | The multi-segment AE sensor measures the light reflected from the subject. |
| J | : | The EOS determines and stores the appropriate flash power required to render the scene naturally by comparing the metering results from G and I, identifying abnormally reflective areas (hot spots) and point-blank reflective areas (and either ignores these areas or de-emphasizes their weighting in the subsequent calculation), taking into account the lens-to-subject distance, and running algorithms to estimate the subject's zone and find the weighted average of the sensor output in the corresponding area. |
| K | : | The EOS transmits the flash power to the 430EX II (as a multiple of the preflash) and sends the main flash command (this completes the flash exposure adjustment). |
| L | : | The EOS adjusts the exposure according to the combination of E and F (to expose for the background). |
| M | : | The EOS processes the image taking into consideration the color temperature - transmitted from the 430EX II - at the moment the flash fired. |
| N | : | The photo is complete. |
· Characteristics of the E-TTL II autoflash system
Below are listed some of the characteristics of the E-TTL II autoflash system.
| (1) | Provides easy operation of automatic flash photography and a natural ambience to photos. |
| (2) | When using the flash in low-light situations or in the aperture priority AE mode, the flash switches to auto slow sync operation, which makes it possible to expose both the subject and the background properly. *A tripod is needed because of the slow shutter speeds in this case; however, hand-held shooting may be possible in some situations by increasing the ISO speed. |
| (3) | Able to independently adjust the background exposure and the flash subject's exposure. |
| (4) | When using the flash after setting the background exposure manually, the manual background exposure setting is preserved and the system controls the flash exposure automatically (based on the manually set aperture). |
| (5) | E-TTL II autoflash can control complex flash lighting situations, such as using multiple wireless flash units. |
This concludes this month's tour of the 430EX II and the E-TTL II autoflash system. Just think of the 430EX II as a more powerful flash unit that conceptually works just like your built-in flash. Test it out for yourself on your camera.