Canon T4i Flash

Canon EOS Rebel T4i Flash

The Rebel T4i's built-in flash has a guide number rating of 43 feet (13 meters) at ISO 100, translating to a range of about 12 feet at ISO 100 with either kit lens at wide-angle (at f/3.5) and about 7.5 feet at telephoto (at f/5.6). Coverage is specified at 17mm or 28mm equivalent. The Canon T4i gives you a lot of control over flash exposure, allowing you to adjust flash and ambient exposure independently of each other, in one-half or one-third EV increments. This makes it easy to balance flash and ambient lighting for more natural-looking pictures. The Rebel T4i also uses E-TTL II control for both the built-in and compatible external flashes, a standard that promises and seems to deliver better, more balanced exposures. (TTL refers to "Through The Lens" metering.) Both evaluatative and average E-TTL II metering modes are available, and the flash can be timed to fire immediately after the first curtain opens, or right before the second curtain closes, allowing for motion trails that lead or follow the subject position at the moment the flash fires.

Another nice touch is the Canon T4i's Flash Exposure Lock function, which fires the flash under manual control before the actual exposure, to determine the proper exposure setting. This struck us as very handy, akin to the more conventional autoexposure lock function for handling difficult ambient lighting conditions. A Flash Exposure Compensation feature controls the flash exposure +/- 2 stops in 1/2 or 1/3-stop increments.

As you'd expect, there is a dedicated flash hot-shoe on the Canon T4i's pentamirror housing, for use with external flash units. Like most consumer SLRs, the Canon T4i offers no PC-Sync connector for triggering studio strobes, etc. Maximum flash x-sync speed is 1/200-second.

The 7D, 60D and T3i were the first Canon SLRs to support wireless flash control using the built-in flash, and the Canon T4i follows suit. That is, the T4i's built-in flash can act as a controller or commander to one or more remote wireless flashes. You can have the built-in flash contribute to the exposure, or just command the remote flashes. Like that of the 60D, the Canon T4i's wireless flash capability supports four channels and defines two groups (the 7D defines three groups). Exposure compensation and flash ratio of 1:8 to 8:1 can be set on a per-group bases, allowing a lot of control over how multiples flashes contribute to the final exposure. Additionally, there's an Easy Wireless Flash mode, which simply fixes the flash strobes to all operate as one group with a 1:1 flash ratio.

Canon's Speedlite 270EX, 270EX II, 320EX, 430EX II, and 580EX II (as well as certain of its historic flash models) enable advanced features such as true FP (focal plane, referred to as HS) flash sync, flash exposure bracketing with external flash units, flash modeling, and E-TTL II exposure control. FP sync requires a flash unit to provide uniform light output for a relatively long period of time, long enough for the focal plane shutter curtain to fully traverse the sensor plane. Uniform, long-duration flash pulses like this permit use of shutter speeds as high as the 1/4,000-second maximum that the Canon T4i is capable of. This can be invaluable when you want to exclude ambient light from the exposure.