Doug Kerr
Well-known member
Over the last week or so I have posted a number of essays discussing relationships in exposure metering as practiced by traditional free-standing exposure meters, their "photographic exposure recommendation" then being used to set shutter speed and aperture on a digital camera.
Of course today that technique is used by few photographers (and thus my essays are of only archeological interest). Rather we tend to use the automatic exposure control functionality of our modern digital cameras. That functionality involves increasingly-sophisticated algorithms operating on measurements of scene luminance at many points in the image, possibly even at each sensel.
Yet we still have the opportunity to set the sensitivity of the camera (as an "ISO number"), or have the camera choose that for us. How does that fit into modern types of exposure control?
I have almost no information on that. We might suspect that for a test shot of a uniform-luminance scene (such as a test card), the phtometric exposure on the sensor would be the same as we would expect for a shot controlled by a traditional exposure meter, with some (unknown) value of K. But maybe not. And what might that value of K be?
Best regards,
Doug
Of course today that technique is used by few photographers (and thus my essays are of only archeological interest). Rather we tend to use the automatic exposure control functionality of our modern digital cameras. That functionality involves increasingly-sophisticated algorithms operating on measurements of scene luminance at many points in the image, possibly even at each sensel.
Yet we still have the opportunity to set the sensitivity of the camera (as an "ISO number"), or have the camera choose that for us. How does that fit into modern types of exposure control?
I have almost no information on that. We might suspect that for a test shot of a uniform-luminance scene (such as a test card), the phtometric exposure on the sensor would be the same as we would expect for a shot controlled by a traditional exposure meter, with some (unknown) value of K. But maybe not. And what might that value of K be?
Best regards,
Doug