The technical description is a picture where all the tones are squashed into the brighter end of the tonal scale and where the highlights may be completely ‘clipped‘ (lost). The artistic description is a photo that’s lighter than the photographer intended.
Exposure explained
Exposure is a big, BIG subject. Even today, getting the exposure right is both an art and a skill, and however sophisticated the in-camera metering systems become, the photographer is still the only one who knows what the picture needs to look like.
Essentially, you control the exposure using shutter speed (the length of the exposure), the lens aperture (how much light it lets through) and the ISO setting (the sensor's sensitivity setting). Each of these is a subject in its own right.
Cameras offer a variety of metering systems to measure the light, and you can choose how to control the shutter speed and lens aperture – or let the camera set them both – using the camera's exposure modes.
So here's a selection of articles about everything related to exposure – how it works, the tools available, and why the camera won't always get it right.
Photo by Annie Spratt on Unsplash
Exposure latitude
A term used to describe a film’s tolerance to overexposure and underexposure and its ability to capture tones in the brightest and darkest parts of a scene, even in high-contrast lighting. The modern-day equivalent with digital sensors is dynamic range, though sensors rarely approach the dynamic range (exposure latitude) of film.
Zone System
A system developed by the great landscape photographer Ansel Adams for measuring the light levels throughout a scene and allocating them to ten brightness ‘zones’. The idea was to develop the film to a specific level of contrast that captured the full range of tones and make appropriate artistic interpretations with dodging and burning during the print-making process. It worked well with the very exposure tolerant sheet films of the day, where each negative was processed individually, but it’s mostly of academic interest today since digital sensors don’t offer this extended exposure latitude.
Underexposure
Where a picture comes out darker than you expected because of the way the camera has adjusted the exposure, or where you deliberately make the photo come out darker for dramatic effect.
Shutter speed
The length of time the shutter is open during the exposure and usually quoted as fractions of a second. Each shutter speed is half as long as the one before, for example 1/30sec vs 1/60sec. This exposure ‘halving’ is the basis for balancing up lens aperture and ISO settings. A few cameras have external shutter speed dials but most simply display the shutter speed on the LCD display – you turn a control dial to change the speed.