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State-of-the-Art Technology Fusing Light and Personal Expression
What you see is what you get with E-TTL autoflash and a multi-zone metering sensor. E-TTL autoflash Speedlites broaden possibilities with natural-looking flash lighting. The E-TTL (Evaluative TTL) autoflash system uses the EOS camera's mufti-zone metering sensor to central the flash output. The mufti-zone metering sensor is Iinked to the camera's multiple focusing points so that the metering is weighted at the point where focus is achieved (where the main subject is assumed to be). The existing Iight level is also metered to enhance exposure accuracy. With multiple metering zones, the flash exposure is very precise. The EX Speedlite first fires a preflash whose reflected light is metered by the multi-zone evaluative metering sensor along with the existing light.
(On the left) :
EF 17-35mm f/2,8L USM, 1/90s at f/4 - Fish Market, 10:00
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| The correct flash output is then calculated and stored in memory. Starting from the instant the shutter button is pressed, the E-TTL autoflash system works as shown in the sequence chart below. The optimum flash output is calculated so that the exposure is well balanced between the existing or natural light and the flash illuminating the subject. As with a normal exposure without flash, the flash exposure is centered on the subject (where focus is achieved). Bright or reflective subjects in the background are also detected and the exposure is controlled accordingly. |
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Advanced Speedlite features are fully automatic.
The E-TTL autoflash system calculates and stores the flash
output before firing the main flash. Besides functioning as the main light, the Speedlite can aise be used as supplemental light in a variety of ways. In low light, automatic slow-speed sync exposes bath the subject and background correctly (with aperture-priority AE). For fill flash in daylight, high-speed sync (FP flash) is effective. |
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E-TTL autoflash system operation flow |
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I. Shutter button pressed halfway
Autofocusing and evaluating metering (with the multizone sensor linked to the focusing point) are executed simultaneously. The existing light is thereby metered. |
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2. Shutter button pressed completely.
Preflash is fired, and the reflected light is metered by the multizone evaluative metering sensor. |
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3. The meter readings of the existing light aria preflash are compared and the main flash's output is calculated and stored in memory |
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4 The reflex mirror goes up, the first shutter curtain starts to open, the main flash fires, the film is exposed, the second shutter curtain, and the reflex mirror goes back down. |
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5. The flash exposure confirmation lamp lights. |
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| With FE lock, you can lock the flash exposure for the subject and change the framing while retaining the correct flash exposure. And when the EOS-lV or the EOS-3 is combined with the Speedlite 550EX or the Macro Ring Lite MR-14EX, E-TTL wireless autoflash enables a flash ratio to be set with two slave groups consisting of multiple Speedlite 550EXs. The two Speedlites also feature flash exposure bracketing (FEB), which brackets the flash exposure automatically. All these advanced techniques are now easier than ever before, with a natural-light Speedlite like never before. E-TTL autoflash extends the boundaries of flash photography. |
Part of Canon "Flash Work" / E-Version © by Daniel ROCHA
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