At what distance are the Imatest charts tested? - Printable Version +- Opticallimits (https://forum.opticallimits.com) +-- Forum: Forums (https://forum.opticallimits.com/forumdisplay.php?fid=4) +--- Forum: Sony (https://forum.opticallimits.com/forumdisplay.php?fid=14) +--- Thread: At what distance are the Imatest charts tested? (/showthread.php?tid=1003) |
At what distance are the Imatest charts tested? - Canuck - 11-05-2015 At what distance are the Imatest charts tested for various focal lengths? I am particularly interested in prime lenses for the wide angle, normal, and short telephoto ranges (35mm equivalent). Thanks for a great and very informative site. At what distance are the Imatest charts tested? - Klaus - 11-05-2015 The object magnification is what counts - the focus distance derives from there. Generally we are using: - Full format: 1:34 - APS-C: 1:52 - Four-Thirds: 1:63 As an exception to the rule, we are sometimes using less or more depending on the lens type. Out of curiosity I once tested an full format ultra-wide lens at 1:80 but that didn't really make a substantial difference. Vice versa, a test at 1:10 had a much high impact but then print quality is certainly also a limiting factor. At what distance are the Imatest charts tested? - Canuck - 11-06-2015 Thanks. What is the size of the test chart? At what distance are the Imatest charts tested? - Klaus - 11-06-2015 The std chart is currently 130x90cm (see Lens Test FAQ for details). At what distance are the Imatest charts tested? - joachim - 11-06-2015 Quote:The std chart is currently 130x90cm (see Lens Test FAQ for details).If my algebra is correct, that is about 2m for a standard lens. At what distance are the Imatest charts tested? - Canuck - 11-06-2015 This subject is new to me so forgive me if I am incorrect in saying that I calculated 1.65 meters for a 50mm lens on a full-frame body. At what distance are the Imatest charts tested? - Klaus - 11-07-2015 Quote:If my algebra is correct, that is about 2m for a standard lens. That is correct. http://www.giangrandi.ch/optics/focalcalc/focalcalc.shtml Just enter 900mm (Object size), 24mm (image height), 1.93m (distance) into the form. |