Lens with larger f-numbers take darker images. This is because the brightness of an image relative to the brightness of the scene decreases with the square of the f-number. The focal length to aperture diameter ratio increases when the f-number increases. Since the focal length is further, less light hits the sensor. When the f-number is doubled, the exposure must be increased by four times for the camera to have the same illuminance.
qqqube
Some other kinds of f-numbers are h-stops and t-stops. An H-stop is an f-number for measuring effective exposure based on the area covered by the holes in diffusion discs or sieve aperture and a T-stop is an f-number adjusted to account for light transmission efficiency.
eliot1019
Quick correction from the professor that second bullet's "F-stops" should be "F-number"
randyfan
The following is a brief description detailing the relationship between f-number and depth of field: Smaller apertures, which correspond to larger f-numbers, produce a larger depth of field effect. The larger (wider) apertures correspond to smaller f-numbers and have a shallow depth of field effect. Shallow depth of field is very useful in photography, allowing the possibility to isolate the subject and make it stand out. This is ideal for portraits because the photographer may want the subject to stand out sharply against a blurred background.
jchen12197
In lecture, the professor said to read "Common F-stops" as "Common F-numbers". Are these terms just interchangeable or do they mean something different?
Lens with larger f-numbers take darker images. This is because the brightness of an image relative to the brightness of the scene decreases with the square of the f-number. The focal length to aperture diameter ratio increases when the f-number increases. Since the focal length is further, less light hits the sensor. When the f-number is doubled, the exposure must be increased by four times for the camera to have the same illuminance.
Some other kinds of f-numbers are h-stops and t-stops. An H-stop is an f-number for measuring effective exposure based on the area covered by the holes in diffusion discs or sieve aperture and a T-stop is an f-number adjusted to account for light transmission efficiency.
Quick correction from the professor that second bullet's "F-stops" should be "F-number"
The following is a brief description detailing the relationship between f-number and depth of field: Smaller apertures, which correspond to larger f-numbers, produce a larger depth of field effect. The larger (wider) apertures correspond to smaller f-numbers and have a shallow depth of field effect. Shallow depth of field is very useful in photography, allowing the possibility to isolate the subject and make it stand out. This is ideal for portraits because the photographer may want the subject to stand out sharply against a blurred background.
In lecture, the professor said to read "Common F-stops" as "Common F-numbers". Are these terms just interchangeable or do they mean something different?