F-number / aperture number How can we help? Search Created On17 April 2021byMario Fischer Print You are here: KB Home Dual Optics Knowledge Base (FAQs) F-number / aperture number <Back The F number is the ratio of the focal length and the diameter of the entrance pupil. The smaller the index, the larger the size of the lens.
Created On17 April 2021byMario Fischer Print You are here: KB Home Dual Optics Knowledge Base (FAQs) F-number / aperture number <Back The F number is the ratio of the focal length and the diameter of the entrance pupil. The smaller the index, the larger the size of the lens.
