Camera School
In the second of our series on getting better bird photos, Paul Sterry of Nature Photographers offers five tips on fine-tuning and using your camera’s settings
Settings and fine-tuning are covered in this tutorial
Your camera’s menu and control buttons allow for a multitude of settings options. Many are irrelevant for everyday photography, some are positively unhelpful, but a few are crucial. Familiarise yourself with the essentials, and some basic photographic principles, to get the most from your camera.
1 ISO
ISO is a measure of the sensor’s sensitivity to light: the greater the number the more sensitive the camera is to light. Image ‘noise’ (the equivalent of film grain) increases with ISO but, in good light, the effect is trivial with ISO settings under 800. You might choose 200-400 ISO if photographing relatively static subjects, but switch perhaps to 800-1,000 ISO for birds in flight. Increasing the ISO allows you to use faster shutter speeds and greater depths of field, both advantageous features for action shots.
2 Aperture and depth of field
The depth of field of a lens is the zone of focus either side of the focal plane; with telephoto lenses it is extremely limited, often just a few millimetres. The zone is variable and determined by the aperture of the lens – the larger the f-stop number, the smaller the aperture and the greater the depth of field. In most circumstances an aperture between f/8 and f/11 is advisable.
3 Exposure and exposure compensation
The amount of light reaching the sensor is determined by shutter speed (how long the shutter is open) and lens aperture diameter (given as an f-stop number). There is a direct relationship between the two: narrow aperture by one f-stop (eg from f/8 to f/11) and you double the shutter time needed for the correct exposure at the same ISO. Generally it is best to rely on your camera’s ability to determine exposure automatically and digital sensors can cope with a wide range of brightness and shadows in a single frame. But with a pale bird against a dark background, you will need to think about the exposure. Activate the highlight alert feature on playback (or scrutinise the histogram) to be sure that highlights have not been ‘blown’; if they have then compensate accordingly. Consider using -0.3EV Exposure Value compensation as your default setting; but with a white tern set against dark blue sea you might require -1.3EV or even -1.7EV. No single setting will suit all types of photography so keep monitoring your playback previews and adjust exposure compensation accordingly. Return your settings to your personal default at the end of a session requiring exposure adjustments.
4 Hand-holding and image stabilisation
Some telephoto lenses are simply too heavy to hand-hold for any length of time. But if you adopt this approach with smaller lenses, a rule of thumb gives you some parameters to work with: to minimise ‘camera shake’ shutter speed needs to roughly equal or exceed the focal length of the lens. These days most lenses have inbuilt image stabilisation which enables stability at slower shutter speeds than normal (claims of two stops are made). Remember that image stabilisation works on the camera and lens, and has no effect on a moving subject. And sometimes it can be a disadvantage: when using a tripod under certain circumstances, or fast shutter speed, for example. So be prepared to disable this function at certain times.
5 Image formats
Modern digital image files are huge, and to avoid clogging up their camera’s memory cards, most photographers opt to save their images in compressed format. There are two routinely used options: RAW format, where lossless compression produces relatively large files; and JPEG format, where adjustable compression is not lossless, but the resulting file sizes are relatively small – both have advantages and disadvantages. More information is captured using RAW when compared to JPEG format, and potentially more information can be retrieved from RAW files if, for example, you have subtly ‘blown’ the highlights. But with everyday bird photography, it is almost impossible to tell the difference between results taken using optimum quality JPEGS and those obtained with RAW files. And, if you are shooting thousands of images in a single session, then file size, with its implications for storage and processing, can be significant. Ultimately, it is a personal choice. So, take the same shot in RAW and JPEG and compare them for yourself. Turn off any internal image sharpening in your camera and archive your best images on your home computer as unsharpened TIFF files, a format that does not employ compression. Only apply sharpening to file copies that have been resized to the required output dimensions.