AboutDavid Silver Expertise My name is David Silver. Antique and classic cameras, vintage photographs, general photography and all areas of the history of photography are my expertise.
Experience I've been a professional photographer and a student of the history of photography for nearly 30 years. During that time my collection of vintage cameras and photographic paraphernalia has grown beyond 2000 significant pieces. I've published nearly 70 articles in the field, including 16 in the popular "Buying Classic Cameras" series for PHOTO SHOPPER MAGAZINE from 1995 to 1997, I'm currently a contributing editor for CAMERA SHOPPER MAGAZINE and McKEOWN'S PRICE GUIDE TO ANTIQUE AND CLASSIC CAMERAS, and I've written numerous entries for WORLD BOOK ENCYCLOPEDIA. Portions of my collection have been displayed in museums and special exhibits in the past two decades, and many of the items were photographed as illustrations for books. In 1985 I founded the International Photographic Historical Organization (InPHO), which eventually evolved into its intended purpose as the best first resource for information on the history of photography. I'm also a founding member of several e-mail forums dedicated to specialized areas of photography, and I'm the moderator of the Internet Directory of Camera Collectors (IDCC), which remains the largest and most successful such group in the world. For more information about the International Photographic Historical Organization and its many services, please visit its web pages at:
Expert: David Silver Date: 6/30/2006 Subject: Why Does Macrophotography entail higher exposure?
Question Hi David,
Having grasped why the diameter of the same f stop opening is larger for longer lens, I'm onto a new puzzle. Why does close up photography require higher exposures?
I've put my thoughts on a webpage, going back to first principles with a pinhole camera :-
Just as Newtonian physics, which is so applicable to normal observable phenomena, cannot explain activities at quantum or atomic levels, using an idealized model of photography by pinhole cannot explain the complexities of true optical refraction. Your thoughts expressed on the web page make sense only in an ideal focal range covering an ideal object. Don't forget, in macrophotography it's not just a matter of how close you get...you must also consider how small the object is! We do not take close-ups of an elephant, we take close-ups of a bug sitting on the petal of a flower. An elephant, despite its overall dark color, relects an enormous amount of light. A tiny bug, even if brightly colored, reflects very little light (much of which at close range will scatter too much to be effectively gathered by a lens). And we, the photographers, are MUCH bigger than the bug, such that when we move in closely to take a picture we inevitably block out much of the illumination. There are intuitive and practical issues to consider in macrophotography that are not part of any equation, and "magnification" (which you dwell on in your web page) is not much of a factor at all. Every close-up picture requires careful thought and specific analysis to understand the unique illumination conditions of that particular shot. As much as possible, photographers turn to artificial lighting methods that render the shot as "normal" as they can. There are some outrageous calculations in the physics of optics that do explain the phenomenon of light transmission fall-off in macrophotography (defined as focal ranges inside the focal length of the lens, giving 1:1 magnifcation or greater), much of it due to diffraction, but I'd rather not deal with them. They make my head hurt! Instead think of the practical matters I've explained. The scientists don't, they insist on their ideal world of perfect equations and perfect objects and perfect illumination, and I'm afraid that's why they're often very bad photographers!
