Camera & Lens
Camera & Lens
The exposure triangle is a useful way of describing the relationship between the three aspects of exposure. Each corner of the triangle represents one of the three variables, aperture, shutter speed and ISO. Adjusting just one of these will make the photo darker or brighter and will change the appearance of the photo based on what you have changed. E.g. using a longer shutter speed will introduce motion blur to your photo but also make the photo brighter (increased exposure) due to more light hitting the sensor. The easiest way to understand it is to see the picture.
ISO – In film cameras, the ISO refers to how sensitive the film is to light. In a DSLR the same concept applies, but it refers to the sensor setting instead of film. Basically, the lower the ISO number, then the less sensitive it is to light. If you are out photographing things in the bright midday sun, then you will probably want to use the lowest setting available (probably ISO 100 or 200). Conversely if you are photographing poorly lit scenes then higher ISO settings are in order. Just remember than the higher ISO settings often bring the problem of digital noise (unwanted speckles and spots in your images). Usually the top end DSLRs are better at handling noise problems at higher ISO settings.
Shutter Speed – This one is fairly self-explanatory. Shutter speed simply refers to the amount of time that the shutter on the camera opens for when you take a shot. A shorter shutter speed will result in less light hitting the sensor and will have the effect of “freezing” motion. A longer shutter speed will allow more light to hit the sensor and any movement in the scene will appear blurred in the direction it was moving (“motion blur”) which can often be a desirable effect depending on what you are trying to achieve. Each shutter speed setting doubles (or halves) the speed compared to the next setting. Don’t forget to check out our beginner’s guide to shutter speed priority mode on your camera.
Aperture – This refers to the size of the opening in the lens that lets light hit the sensor. Wider apertures obviously allow more light in and narrower allow less light in. The size of the opening is measured as f/1.4, f/2.8, f/4, f/5.6,f/8, f/16, f/22 etc (commonly referred to as “f stops”). The small the number, the larger the opening and each “stop” up from there effectively halves the size of the opening (and thus the amount of light entering the camera). Aperture also allows you to control depth of field.