Looking at old photographs evokes a wonderful sense of nostalgia in most of us. Whether you’re preserving a special occasion, photographing your favourite place or just taking a happy snap, we’ll give you some technical tips on how to make your picture just a little more perfect!
Last month we gave you the low-down on some serious photographic mumbo-jumbo such as shutter speed and aperture, film speed, depth of field and composition. This month we delve a little deeper into these topics plus a few more, to find out which techniques you need to master in order to make the most of your photographic opportunities.
Although most cameras these days do not use film, light sensitivity is still traditionally described as ‘film speed’, even on a digital camera. The light sensitivity range of a camera is indicated by the ISO number, as defined by the International Organization for Standardization. The higher the ISO, the more light-sensitive the camera’s sensor is. This is useful for low light conditions, but the ‘noise’ increases as the ISO is increased, and the loss of image quality soon becomes evident.
The aperture of a lens determines how much light can travel through the optics. The different sizes of aperture are called ‘f-stops’: the smaller the f-stop number, the larger the lens opening. For example, f2.8 is quite a large aperture that can be used in low light conditions to allow more light into the camera for correct image exposure. The smaller the aperture, the less light enters the image plane. The aperture also affects the depth of field: the higher the f-stop number (i.e. the smaller the aperture) the deeper the depth of field will be, with a wide range of distances in focus. More on this below!
The length of time the shutter takes to close is known as the shutter speed, and it’s one way of determining how much light reaches the image plane. It also allows you to change the way movement is captured: a fast shutter speed freezes motion, and a slow shutter speed can suggest movement in a still photograph through the blur of moving objects, and can create a ‘ghosting’ effect. If the shutter speed is too slow, you are also more likely to get camera shake, which is an undesirable blurring of the entire image.
Depth of field
You can control the extent of image sharpness and subject emphasis by using the phenomenon called ‘depth of field’ – that is, the distance between the closest and the furthest points that are in focus. Use a shallow depth of field when you want to put the focus on a particular area of an image and blur the rest of it, thus emphasising the point of interest. If you want the whole image to be in focus, from objects in the foreground all the way to those in the background, then you will need a deep focus. Essentially, your distance to the subject, the focal length of your lens and the aperture are the factors you must manipulate to control the depth of field.
Understanding the quality of light is important, so when you switch on that flash, decide why you need it and what you want to achieve. The best results usually involve blending the available light with some flash to make the image ‘pop’ or to lighten dark areas and add to the ambient light. Consider diffusing your flash by bouncing it off a wall or ceiling for a soft light quality. Adjust the output of the camera flash to compensate for light lost this way and to balance out the exposure variables.
How to avoid camera shake
The ISO number, aperture and shutter speed have to be coordinated to achieve the correct exposure for the particular conditions you find yourself in. If you are hand-holding the camera and/or photographing a moving subject in low light, push up the ISO and open up the aperture, but avoid shutter speeds of less than 1/60 of a second, or you will probably get camera shake. If you have a steady hand you may get away with a slightly slower shutter speed. When photographing people, they should not be moving if you are shoot at 1/60 or slower. This can prove tricky, so add flash if the situation allows.