through-the-lens metering
Quick Summary
Through-the-lens (TTL) metering is a photography technique where the camera's built-in exposure meter measures the light as it passes through the lens and strikes the film or image sensor. This method allows the meter to account for factors like the lens's angle of view, close-up adjustments, and stray light, providing more accurate exposure readings than external meters.12
Older cameras used separate, handheld exposure meters that measured either incident light (falling on the subject) or reflected light (bouncing off the subject). Modern cameras, especially single-lens reflex (SLR) models, integrate TTL metering systems, often using silicon photodiodes to measure light and automatically adjust shutter speed or aperture for optimal exposure. Some advanced TTL systems even measure light directly off the film or shutter blind (off-the-film or OTF) for precise flash control.12
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technology of photographyExposure-metering systems…coming through the lens (TTL metering) and so allows for the lens’s angle of view, close-up exposure corrections, stray light, and other factors. Some TTL systems divert the light from the lens to a photocell before it reaches the screen (e.g., by beam-splitting arrangements or the use of photocells…
Read More…coming through the lens (TTL metering) and so allows for the lens’s angle of view, close-up exposure corrections, stray light, and other factors. Some TTL systems divert the light from the lens to a photocell before it reaches the screen (e.g., by beam-splitting arrangements or the use of photocells…
Read More- technology of photographyAutomatic meter control
Cameras with through-the-lens (TTL) exposure meters—and also hand-held meters pointed at the subject—measure the average reflected light intensity, yielding reliable exposures for subjects of average contrast and brightness distribution. Subjects of extreme contrast or very bright or dark dominant areas need overriding exposure corrections; automatic cameras often…
Read MoreCameras with through-the-lens (TTL) exposure meters—and also hand-held meters pointed at the subject—measure the average reflected light intensity, yielding reliable exposures for subjects of average contrast and brightness distribution. Subjects of extreme contrast or very bright or dark dominant areas need overriding exposure corrections; automatic cameras often…
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