relative aperture การใช้

• The simpler half-lens was of adequate quality for the narrow angle of view and small relative aperture.
• Combinations of shutter speed and relative aperture that resulted in the same exposure were said to have the same " exposure value"
• Zoom lenses typically have a maximum relative aperture ( minimum f-number ) of 2.8 to 6.3 through their range.
• High-end lenses will have a constant aperture, such as 2.8 or 4, which means that the relative aperture will stay the same throughout the zoom range.
• Extremely small apertures such as f / 64 can be used without issues of diffraction on the lenses, of much larger focal length than those used for smaller images ( a small relative aperture is still a fairly large hole, reducing diffraction ).
• A more typical consumer zoom will have a variable maximum relative aperture since it is harder and more expensive to keep the maximum relative aperture proportional to the focal length at long focal lengths; 3.5 to 5.6 is an example of a common variable aperture range in a consumer zoom lens.
• A more typical consumer zoom will have a variable maximum relative aperture since it is harder and more expensive to keep the maximum relative aperture proportional to the focal length at long focal lengths; 3.5 to 5.6 is an example of a common variable aperture range in a consumer zoom lens.
• Its film was Ilford Photo SR101 in the form of 0.93in discs punched from 35 mm strip; weight 801; diameter 1.5in; length 1.25in; field of view 186 deg; exposure time 0.3 millisec; effective relative aperture, approximately f / 8; 192 cameras were made in the initial production run.
• The f-number ( relative aperture ) determines the depth of field, and the shutter speed ( exposure time ) determines the amount of motion blur, as illustrated by the two images at the right ( and at long exposure times, as a second-order effect, the light-sensitive medium may exhibit reciprocity failure, which is a change of light sensitivity dependent on the irradiance at the film ).
• The 1961 ASA standard PH2.12-1961 " American Standard General-Purpose Photographic Exposure Meters ( Photoelectric Type ) " specifies that " The symbol for relative apertures shall be f / or f : followed by the effective f-number . " Note that they show the hooked italic f not only in the symbol, but also in the term " f-number ", which today is more commonly set in an ordinary non-italic face.
• For infinitely distant objects the radius Of the chromatic disk of confusion is proportional to the linear aperture, and independent of the focal length ( " vide supra ", " Monochromatic Aberration of the Axis Point " ); and since this disk becomes the less harmful with an increasing image of a given object, or with increasing focal length, it follows that the deterioration of the image is proportional to the ratio of the aperture to the focal length, i . e . the " relative aperture . " ( This explains the gigantic focal lengths in vogue before the discovery of achromatism .)