Exposure is one of the key elements in photography that is often overlooked by the automatic settings on your camera. In this introduction, I will try to explain what exposure is and how it can be manipulated to alter your images. As with most aspects of photography, practice is key to finding what works for you, your camera and your finished image. Although there are ‘guidelines’ in photography, any rules that govern ‘how to take the perfect image’ should be broken (repeatedly!)
So what is meant by exposure
In simplest terms, exposure to how much light is hitting the photosensitive material (film or digital sensor). Generally, you are trying to replicate the image with what you see with the naked eye. Too much light on the sensor and the image is too bright (overexposure) and too little light on the sensor and the image is too dark, with tones all muted and mixed (underexposure).
Your eyes are amazing and can detect the smallest variations in light (contrast) and is far more dynamic than the limited range that is possible with your camera. (I used to work for an eye surgeon and the abilities of the human eye still fascinate me. The range of colours and the constant feedback to the brain). Work with the fixed limitations of your camera, to get the image that you would like.
In this image (House of Parliament), the clock face of Queen Elizabeth Tower (Big Ben) is overexposed (there is too much light to see the details on the clock face). However, if I were to expose for the clock face to look at the details, then the rest of the building, the bridge and even the bus on the bridge would be underexposed. Also though I could see all these aspects with my eyes in full dynamic range, the range of my camera would not allow for this. Hence the finite dynamic range of the camera is the only constraint that you are working with.
For every image, there isn’t a ‘right or wrong’ exposure. When I was attending photography meetups and workshops before, students were always asking what should my aperture be, what should my ISO be, why am I not getting the image I want. This because there are no hard and fast answers! Each subject is different (is the light itself the matter?), the light changes second by second (especially with the constant clouds in the UK!) and the saturation, vibrancy and drama changes on the exposure.
By underexposing this image of a man on the beach, I would able to capture the pink and blue of the sky in Turkey. Although the man is slightly in shadow and mixed, the sky is vibrant and saturated. No colour or exposure edits were made to this image in post-processing. This image was much lighter in person (with my own eyes) but work with the restraints of your camera.
Underexposure – generally appear darker than the naked eye, leading to possible drama or mood. Can lead to colours being more saturated, toning down highlights but can cause of loss of detail in the shadows and low tones
Overexposure – generally appear lighter or whiter than the naked eye, can cause a sense of lightness and romantic feel of the image (hence why so many Instagram filters give the appearance of overexposure). Can also create a loss of detail in the highlights and too much can cause an almost abstract feel to the image.
Exposure is a product of three camera controls – ISO, aperture and shutter speed. These three components are known as the photographic triangle. We will discuss each of these components in more detail separately as part of our Photography 101 online guide.
Many artists have advanced their art by breaking the conventional barriers and being non-conformists. Understand the principles and disregard all the rules! You are the creative imagination behind your images.