"F Stop" is a ratio between focal length and lens aperture. When comparing lenses of the same focal length, it is an indication of the lens aperture. The smaller the "F Stop" the wider the lens aperture and the more light the lens allows into the camera. This is important to lenses with adjustable irises (both manual and auto). Our vari-focal, manual and auto-iris lenses have an "F Stop" value of 1.0, giving a far better aperture than most and consequently a better image, particularly in lower light conditions.

Focal Length
The Lens Iris