Affiliation:
1. University of Georgia, Athens, GA;
Abstract
In this study, we propose a novel and direct method of determining the focal length of a converging or diverging lens using a smartphone. The standard optical sensor used in modern smartphone cameras is an active-pixel sensor called the complementary metal–oxide–semiconductor (CMOS). The CMOS is covered by an assembly of five to seven camera lenses that can be moved along the axis of the camera to electronically adjust its overall effective focal length, i.e., the autofocus feature. This collection of lenses, referred to as a system of adaptive optical lenses, can be treated as a single effective converging lens that forms a real image on the CMOS sensor array. We assume that the image distance between the CMOS sensor array and the smartphone camera lens (SCL) is a constant. Based on this assumption, a two-step procedure is proposed to accurately obtain the focal length of a lens without the need for additional lenses.
Publisher
American Association of Physics Teachers (AAPT)
Subject
General Physics and Astronomy,Education
Reference11 articles.
1. CMOS image sensors
2. Optical analysis of miniature lenses with curved imaging surfaces
3. “Basic optics system OS-8515C: Instruction manual with experiment guide and teachers’ notes,” https://d2n0lz049icia2.cloudfront.net/product_document/Basic-Optics-System-Manual-OS-8515C.pdf.
4. Measuring the focal length of a camera lens in a smart-phone with a ruler