The three elements of the exposure triangle are aperture, shutter speed, and ISO settings.
Changing one of these elements means that you will have to change one or both of the other two in order to achieve a properly exposed image.
This article will focus on the effect of the ISO settings and what it means to your photograph.
In simple terms, the ISO settings deals either with the sensitivity of the film (in old film cameras), or the sensitivity of the sensor, (in digital cameras).
With film cameras, this setting is fixed based on the film type you put in, this meaning you only have the aperture or shutter speed in your control (so choose your film wisely before setting off on a shoot).
However, in digital cameras, you have the ability to change this setting as and when you please.
Various ISO Camera Settings To Choose From
In most digital cameras, there are several options you can choose for your ISO settings. 100, 200, 400, 800, 1600, and some good DSLR cameras go beyond this to 3200 and more. Each time, the value pretty much doubles.
In simple terms, you would set your ISO settings to a low number if you are in bright conditions, or high ISO settings if you are in dark surroundings.
Basically, the higher the number, the more sensitive to light your sensor is.
If you were to pick high ISO settings in a bright sunny environment, then you would find that your image is extremely overexposed and difficult to see what it has captured.
In contrast, if you are taking photos of dusk and were to use low ISO settings, then your image would be underexposed, and would look black.
And this is why it is important to set the ISO first to the environment before composing your shot and deciding on aperture and shutter speed values.
Of course, you can play with your ISO settings to produce creative images. Sometimes over exposed shots can look very good if deliberately made that way.
For example, you can explore form and blend your subject in with the white background over exposing the shot will produce. But you will need to have full mastery of the concept before attempting anything like that.
Another thing to consider with your ISO settings is that the more sensitive you make your sensor (by setting a high ISO value), then the more of a grainy effect you are likely to get.
Also called ‘noise’, images taken in dark conditions are very susceptible to this effect, and your blacks may not look pure and be grainy or noisy.
Many modern digital cameras are overcoming this problem, and this has led to newer models being able to cope with even higher ISO settings before a grainy effect is experienced.
Of course, you may wish some of your images to have a grainy effect, it is not always undesirable.
You can be very creative by allowing a high ISO to dominate your images to convey a different mood or emotion.
Generally though, once you have established the environment you are in, you simply set your ISO settings to relate to that and not touch them again until you change your lighting environment.
This leaves you to focus on the other two parts of the exposure triangle, where you will establish which priority you need to focus more on, depending on the subject you are shooting.
Your ISO settings are normally the first consideration you make when composing a photograph, so establish the environment you are in, and set your ISO accordingly.
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