Canon SPEEDLITE 420EX: Fit for Digital?

So you got that fancy digital SLR camera but flash exposures still look kind of flat and unappealing. Red eyes are still not fully eliminated (despite pre-flash) and far objects underexposed. The problem is not your technique but the limited capability of any built-in flash due to position and size.

An external flash helps out, and top models pack massive power and many features for demanding amateurs and professionals alike. The Canon Speedlite 420EX strikes a good balance between professional features and cost. Note: Not all cameras support all functions of an advanced flash like the 420EX. I am using the Digital Rebel with a modified firmware to enable FEC (Flash Exposure Control) in the camera and mirror lock-up. Even without the changes, this camera falls into the Type-A category and supports e-TTL, High speed sync and FE lock. So called Type-B cameras force the 420EX into the less powerful TTL mode which excludes pretty much all features mentioned above. Some point-n-shoot cameras provide a hot shoe as well but be advised that this is almost exclusively TTL only.

An external flash also helps to reduce power consumption of the camera and in the case of the Digital Rebel to reach about 600 exposures on a standard battery charge. Depending on flash exposure, the 420EX will reach between 200 and 1400 flashes and on average that should be a good match for the camera rating. (Canon points out that the flash count is based on alkaline batteries and 1500mAh NiH batteries (rechargeable) only yield about 75% as many flashes. Nevertheless, the latest NiH batteries reach up to 2500mAh and that should be at least on par with the yield from alkaline batteries. Unchanged is the recycling time of the 420EX, which is naturally handicapped over the 1.5V alkaline batteries since rechargeable batteries only provide 1.2V on average no matter how many mAh.)

The excellent manual is included in an English version and French. Each feature is discussed in very good detail, but very few specifics pertaining digital photography. The flash comes with a pouch and a stand.


MAIN FEATURES

The hot shoe (mounting foot) is e-TTL compatible and a locking ring makes sure that the flash doesn't slide off. The battery chamber holds 4 AA batteries and the lid is hinged to the housing so it doesn't get lost.

AF Assist: The front bears an AF assit beam emitter which projects a red cross pattern to ease focusing. It works amazingly well and allows even in dim rooms a safe focusing on a uniformly white wall. This is a significant improvement over the white light assist that's built in to the Digital Rebel. The extended range of up to 7m for the AF Assist is a nice side effect of this feature.

Power: Typical built-in flashes have limited power due to size and available battery power from the camera. Most internal solution are rated at about 5 - 7 m to be effective (as they usually don't zoom either). The 420EX is rated to reach up to 23m in the widest setting (24mm) and even 42m at the most focused setting (105mm). Consider the up to as depending on the reflectivity of your motiv. It may absorb more light and shorten this distance significantly. Further, the AF assist may not reach that far anyway (if no good contrast is available).

Recycle time: A close cousin to the used power is the recycle time in a sense that the 420EX is capable to adjust the output power and with it the used power from the built-in buffer. Further it depends on the used batteries' capacity how quickly the flash can recharge. In the lowest setting (FEC = -2 stops) and with fresh alkaline batteries the flash is able to recover in less than a second. For the maximum output power (FEC = +2 stops), this time increases up to 7.5 seconds. For normal use I measured around 4 - 5 seconds on average with rechargeable NiH batteries (1850mAh). The shorter the recycling time the less power has been used to refresh and most likely more flash can be fired. In fact, for close-ups the used energy is so minimal that recycling is virtually instant.

Swivel: The flash head can swivel upward and provides click positions at 0, 60, 75, and 90 degree. This allows to use flash either direct or bounce off the ceiling. The result are more natural flash exposures for most bounce settings. For a slightly different effect or if there is no reflective (preferably white) ceiling, the head can also swivel right (up to 90 degree) and left (up to 180 degree). Upward and sideways swivel can be combined at will. This may be the single argument for the 420EX versus the 220EX which is fixed and allows direct exposure only.

Zoom: The covered area of the flash is adjusted automatically according to the focal length of the lens. The longer the focal length of the lens the smaller the coverage area at the same distance. In return the flash can be more focused and therefor reach farther. The 420EX adjusts between 24mm and 105mm focal length and the equivalent coverage area. These numbers equal 35mm photography and when using an APS sized film or sensor, the coverage area translates into 15mm to 65mm. Nevertheless, the 420EX measures the readout from the lens (true focal length), which is correct for 35mm and safe (oversized) for APS sized film and sensors. (i.e. Using 35mm lens setting on a Digital Rebel will tell the 420EX to cover 35mm which is actually the equivalent of a 56mm focal length.)

FP Flash: Normally the flash fires when the shutter opens and longer exposures record what happens after the flash. So-called Second-Curtain Syncronization (FP Flash) allows to fire the flash right before the shutter closes. This is especially important for moving objects to maintain the correct sense of motion. This function is activated on the 420EX and controls the timing based on the camera's feedback.

Slave: The 420EX cannot control other flash units but it functions as a slave when used with a master unit (i.e. 550EX or ST-E2). Unfortunately most Canon SLR cameras don't have a master unit built in. Nevertheless, depending on flash setup and your ability to dish out for several flash units the result can be creative and of excellent quality due to the full e-TTL capability even in multiflash setups.

Modeling Flash: Describes the ability of your camera to preview Depth of Focus and fire the flash unit at 70Hz for 1 second. If your camera falls into that category, this great feature allows to preview shadow cast which is most important for multiunit setup and film photography. (Digital cameras might as well just shoot a picture and review that for a preview. Many cameras, including the Digital Rebel, do not support this function.)


SUMMARY

I have been using the built-in flash for many years and never dared to invest in an advanced external flash like the 420EX. Now that I used it for a week, I must admit that I feel I should have done that earlier. However, the needed $165 are still a significant consideration.

Size and user interface of the 420EX are well balanced and even for novices quickly to master as there is very few manual controls on the 420EX. After all, one can always shoot in full automated mode and the e-TTL guarantees significant improvements over most integrated flashes. Unmatched by any integrated solution is the bounce capability which boosts the natural appeal significantly. This may also be the one reason to step up to a 420EX instead of a 220EX. (A 550EX is overkill for users that don't need more than one flash.)

For getting the most out of an advanced flash unit like the 420EX, make sure to use it with a fully e-TTL capable EOS camera to access all the functionality. (Canon refers to that as a Type-A camera.)

For my pictures the 420EX did improve flash photography significantly and focusing in low light conditions improved a lot as well. Given that these were exactly the most annoying issues I had indoors, the new flash unit helps a great deal and is worth every single Dollar of the $165 that I paid.

The only feature I cannot access with the Digital Rebel (EOS 300D) is the modeling feature. Given the digital nature of the camera it's not really necessary anyway.

© 2004, theuerkorn