Definitions
There is 1 meaning of the phrase
Focal Ratio.
Focal Ratio - as a noun
The ratio of the focal length to the diameter of a (camera) lens system
Synonyms (Exact Relations)
f numberspeedstop numberExample Sentences
"The telescope has a focal ratio of f/10."
"Photographers often prefer lenses with a wide focal ratio."
"A lower focal ratio allows for brighter images."
"A higher focal ratio is better for capturing more details in the image."
"The focal ratio greatly affects the exposure time needed for astrophotography."
