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Old Jun 19, 2003, 1:50 PM   #1
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Default Is there a relation with Depth-of-Field and Metering?

As most of us know, consumer digital cameras - from your lowly HP 1.0MP to your high-end Minolta 7Hi, has a small CCD sensor in comparison to 35mm film. The two common standard sizes are .555" and .666". I have learned in the past that my Olympus C-4000 (for example) has 5 times (5x) the Depth-of-Field (DOF) compared to 35mm film. Therefore, my C-4000's setting of f2.8 has the same DOF as f14 in 35mm equivalency.

The question is: Does the camera meter for a "true" f2.8 aperture, or is it metering at f14? If the latter, then does that mean if I had a 35mm camera, and set the aperture to f2.8, the meter would set a faster shutter speed VS. my Olympus C-4000 which has 5x the DOF?

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Old Jun 19, 2003, 3:16 PM   #2
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No, the shutter speed and f-stop are all the same regardless of what camera! ie take a meter reading with a handheld meter and the same settings would apply to any digicam, Minox, APS, 1/2 frame, 35mm and all the way up to Medium format/View cameras! 8)

This DOF differences however exist even before digicam between the different film formats... :lol:
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Old Jun 19, 2003, 5:50 PM   #3
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Default Re: Is there a relation with Depth-of-Field and Metering?

Quote:
Originally Posted by The_Oz
As most of us know, consumer digital cameras - from your lowly HP 1.0MP to your high-end Minolta 7Hi, has a small CCD sensor in comparison to 35mm film. The two common standard sizes are .555" and .666". I have learned in the past that my Olympus C-4000 (for example) has 5 times (5x) the Depth-of-Field (DOF) compared to 35mm film. Therefore, my C-4000's setting of f2.8 has the same DOF as f14 in 35mm equivalency.

The question is: Does the camera meter for a "true" f2.8 aperture, or is it metering at f14? If the latter, then does that mean if I had a 35mm camera, and set the aperture to f2.8, the meter would set a faster shutter speed VS. my Olympus C-4000 which has 5x the DOF?
Although the diameter of your digital f2.8 is (according to you) the same size as the f14 on the 35mm, you have to remember that your lens numbers will be much smaller than the 35mm equivalent because of the much smaller size of the CCD.

The actual definition of the F-stop number is a mathematical relationship of the focal length of a lens and the size of the lens opening or aperture. F-stop is defined as focal length in mm of the lens divided by diameter of the lens opening in mm. Because the *actual* focal length of the lens is much smaller (due to the size of the CCD being much smaller than 35mm film), the aperture opening will also be much smaller...but because it's a ratio it should give you the same effect that the equivalent F-stop on a 35mm.
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