There are three simple points to remember when using your SLR camera in the field. If you gain an understanding and mastery of these three aspects of camera use, you will be able to add a solid foundations to your photographic repertoire.
The aperture is defined by how big or small you decide to make your F-Stop. The lower the F-Stop (eg: f2.8) the wider the aperture on the lens. Lower F-Stops mean that there is more light coming through the lens in a set amount of time, thus making the shutter speed quicker. Lower apertures are used primarily for portraits and in low light.
As a simple rule of thumb when out in the field:
Use a small F-Stop of 2.8 – 5.6 for portraits of cats, people and birds.
Use a medium F stop of 9 – 10 for elephants, rhinos and giraffes
Use a larger F-Stop of 16 or 18 for landscapes, trees, herds of animals and group photos
By setting your SLR camera to take photographs based on the aperture priority, it will automatically adjust your shutter speed to suite it.
The best time to take pictures based on your chosen shutter speed is in low light or exceptionally bright light. If it is dark, try and set a longer shutter speed so that the picture will come out looking light enough. Be sure to use a beanbag when doing this as long shutter speeds require that the camera is steady.
I also set my shutter speed when attempting panning photographs of animals running in the low light. If you set your shutter to about 1/60 if allows enough time for the background to blur whilst the animal to be kept in focus provided your focal point is maintained during the entire shot.
The ISO of a camera denotes how sensitive the image sensor is to the amount of light present. The higher the ISO, the more sensitive the sensor and the greater the potential for taking pictures in low-light situations. The lower the ISO, the less sensitive the sensor and the greater the potential for taking pictures in harsh light situations.
For morning and afternoon shooting it is reasonable to keep your ISO around 400, however some of the more advanced cameras have the capabilities to set ISO much higher. Test your camera out and use an ISO that works for you, just be careful that your photographs are not to noisy.
When you increase the ISO, the image sensor records a fainter light signal, however it also records fainter noise (any signal that is not attributed to the light from your subject). The ratio of light signal to noise determines the ‘noise’ element in your photograph.
One Other Tip:
If you want to create great silhouettes then drop your camera down a few stops. Your ranger will be able to show you how to do this, however the more you drop the stops the more saturated the background will become against the foreground darkened forground image. Best used in early morning or late afternoon.
I use this effect a lot when photographing silhouettes of trees, people, horizons just after the sun has set and the sky gets colorful. How have you found these three aspects affect your ability to take better pictures? Let me know in the comments section below.