Kenko (2012), Auto Extension Tube Set Directions for Use. Kenko Tokina Co., Ltd., Tokyo.
Leica (2013a), Leica Summilux-M 35 mm f/1.4 ASPH Technical Data. Leica Camera AG, Solms.
Leica (2013b), Leica Summilux-M 50 mm f/1.4 ASPH Technical Data. Leica Camera AG, Solms.
Harold M. Merklinger (1992), Depth of Field Revisited. Dartmouth, Nova Scotia. A short version of a series of articles that first appeared in Shutterbug in 1991-1992. The author wonders why he rarely achieves satisfactory sharpness with the hyperfocal distance, and shows why another focusing strategy gives better results.
Hubert H. Nasse (2011), Planar—The history and features of one of photography’s most important high performance lenses. Carl Zeiss, Oberkochen, 5.
Gunther Wegner (2017), Diana lernt fotografieren. gwegner.de Verlag, Ahrensburg. The basics of photography from a practical point of view. Chapter 4 on image composition is highly recommended, especially for beginners.
Zeiss (1997a), Depth of field—An insider’s look behind the scenes. Camera Lens News No. 1, Carl Zeiss, Oberkochen, 3.
Zeiss (1997b), Resolution of camera lenses: Where are the limits—and why? Camera Lens News No. 2, Carl Zeiss, Oberkochen, 2-3. Limitations of resolution due to diffraction, depth of field, film, and motion.