It’s probably a matter that need not concern users of budget-priced fixed lens compact digicams but it is a subject of great matter to those who own DSLRs and other sundry ‘clever’ compacts. Exposure is where it all begins and, sometimes, disastrously ends.
The relationship of lens aperture and shutter speed is one which all too often unnerves the novice. Throw in the charms and complications of the ISO setting and you often have a maze without an exit.
Author Stansfield sets out the territory be explaining the differences between exposure and metering: ‘Exposure is a term that describes the actual settings used to capture an image, whereas metering provides only a suggested group of settings that you are free to ignore, over-ride or adjust …’
A helpful section on lens aperture takes the reader through the mysteries of f stops, how they are determined and relate, answering the eternal question as to why f8 is double the exposure of f11! And why you can capture a photo with the lens set at f4 and and exposure of 1/1000 of a second that will equal one taken at f5.6 and 1/500 second.
Acknowledging the role of post processing, the book explains that primary exposure depends on a camera’s settings of lens aperture, shutter speed and ISO setting when making the initial exposure, while secondary exposure refers to post-exposure corrections made in-camera or with the help of applications such as Photoshop after downloading.
Explanations then follow on the role of auto exposure, Program, aperture and shutter priority as well as manual exposure. Other modes such scene mode and picture styles are explained.
The role of differing lens focal lengths is discussed with especial reference to the effect that a wide angle lens setting can have when compared to that of a narrow (ie tele) lens setting: the wide can often include large areas of bright sky, dramatically affecting correct exposure.
Other topics include dealing with over- and underexposure, light and its variables, composition, metering modes, white balance, depth of field, image noise, dynamic range, ND and polarising filters, High Dynamic Range and more.
An amusing sidelight is the brief reference to reciprocity failure, an issue that used to affect film photographers when making extended exposures in low light. Worry no more! Digital cameras have killed that one!
For such a small book (15x18cm) there is a surprising depth of information. To be realistic, while the book’s small size leads to its pocketability, the subject is not one that you will need to consult in the field … however, the compact size makes the info within its 192 pages very accessible.
At the back of the book are a useful, slip out pair of reference cards giving depth of field tables for a variety of lenses and digital sensor sizes.
Author: A Stansfield.
Length: 190 pages.
ISBN: 978 1 906672 99 7.
Price: Get a price on Understanding Exposure at Amazon where it is currently 22% off.