)2&86,1* WKH 9,(:&$0(5$ $6FLHQWLILF:D\ WRIRFXV WKH9LHZ&DPHUD DQG (VWLPDWH'HSWKRI)LHOG J E\+DUROG00HUNOLQJHU )2&86,1* WKH 9,(:&$0(5$ $6FLHQWLILF:D\ WRIRFXV WKH9LHZ&DPHUD DQG (VWLPDWH'HSWKRI)LHOG E\ +DUROG00HUNOLQJHU 3XEOLVKHGE\WKHDXWKRU 7KLVYHUVLRQH[LVWVLQ HOHFWURQLF 3') IRUPDWRQO\ ii Published by the author: Harold M. Merklinger P. O. Box 494 Dartmouth, Nova Scotia Canada, B2Y 3Y8 v.1.0 1 March 1993 2nd Printing 29 March 1996 3rd Printing 27 August 1998 1st Internet Edition v. 1.6 29 Dec 2006 Corrected for iPad v. 1.6.1 30 July 2010 ISBN 0-9695025-2-4 © All rights reserved. No part of this book may be reproduced or translated without the express written permission of the author. ‘Printed’ in electronic format by the author, using Adobe Acrobat. Dedicated to view camera users everywhere. FOCUSING THE VIEW CAMERA iii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iv Merklinger: FOCUSING THE VIEW CAMERA &+$37(5 7DEOHV FRQWLQXHG +LQJHOLQHWLOW (IIHFWLYHWLOWIRUERWKVZLQJDQGWLOW /HQVWLOWDQJOHIRUJLYHQIRFDOOHQJWKfDQGGLVWDQFHJ 'LVWDQFHJ IRUJLYHQWLOW %DFNIRFXVGLVWDQFHA 'HSWKRI)LHOG /HQVWRSODQHRIVKDUSIRFXVGLVWDQFHD +\SHUIRFDO'LVWDQFHH ,QGH[WR7DEOHV UHSHDWHG %ODQN&KDUWV ,QVHUWVSURYLGHGZLWKSULQWHGYHUVLRQ 7KH1DWLRQDO$YLDWLRQ0XVHXP2WWDZD 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There is an important caveat, however. I was never happy with some of the technical terms I used in that article and have struggled to find new language. Specifically, in the Shutterbug article I used the term “bore sight’ to describe an important (vector) direction for view cameras. Those words better describe a different direction. The term derives from fire arms where the bore sight is simply established by by looking down the bore of the gun, from breech to muzzle. The camera equivalent is probably looking through the center of the lens with one’s eye positioned in the geometric center of the ground view camera glass screen. To actually do this would, of course require a hole in the ground glass and the removal of the lens components leaving only the diaphragm. At the risk of confusing the readers of that earlier article, I have changed the meaning of “bore sight” to mean precisely what I have just described. The original direction I used that term for, I have relabeled the “principal axis” of the camera. Please note that this is the principal axis of the camera, not the lens. This principal axis is established primarily by the orientation of the film, or electronic image sensor. It is the principal axis that determines the apparent perspective of the image. I am told that, in the usual language of perspective, what I am calling the principal axis is normally termed “the line of vision”. For a ‘normal’ camera, that is for a camera that has its lens axis perpendicular to the film and centered on the image, the principal axis of the camera, the axis of the lens and the bore sight all coincide. This coincidence of important axes simplifies the associated optical physics considerably. This coincidence is an assumption that underlies nearly all descriptions of photographic optics that I have seen. For view cameras, where it cannot be assumed that these three axes coincide, the mathematics unfortunately gets rather complex. Yet the fundamental principles are still relatively simple, and are within the grasp of all of us to understand. Essentially, the Scheimpflug rule and the hinge rule explain everything; add one extra consideration and depth-of-field is explained also. In order to assist people visualize the Scheimpflug and hinge rules, I generated a few animated computer “movie” files. These files can be found on my web site: http://www.trenholm.org/hmmerk/HMbook18.html. I would also like to acknowledge that in spite of my best intent, I have realized that I did make one or two unintended mathematical approximations (in both books) concerning depth of field and perhaps should