ISO in Digital PhotographyIn Digital Photography ISO measures the sensitivity of the image sensor.
The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain.
Higher numbers mean your sensor becomes more sensitive to light which allows you to use your camera in darker situations. The cost of doing so is more grain (although cameras are improving all the time and today many are able to use high ISO settings and still get very useable images).
An example of a situation you might want to choose a higher ISO would be photographing an indoor sporting event where the light is low and your subject is moving fast. By choosing a higher ISO you can use a faster shutter speed to freeze the movement.
The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain.
Higher numbers mean your sensor becomes more sensitive to light which allows you to use your camera in darker situations. The cost of doing so is more grain (although cameras are improving all the time and today many are able to use high ISO settings and still get very useable images).
An example of a situation you might want to choose a higher ISO would be photographing an indoor sporting event where the light is low and your subject is moving fast. By choosing a higher ISO you can use a faster shutter speed to freeze the movement.
ISO Settings and GrainAs mentioned – the cost of choosing higher ISO settings is that you begin to get higher grain or noise in your images the higher you go.
This is illustrated below with two enlargements shots
the one on the left is taken at 100 ISO and the one of the right at 3200 ISO.
This is illustrated below with two enlargements shots
the one on the left is taken at 100 ISO and the one of the right at 3200 ISO.
100 ISO is generally accepted as a ‘normal’ or ‘standard’ ISO and will give you lovely crisp shots (with little to no noise/grain).
Most people tend to keep their digital cameras in ‘Auto Mode’ where the camera selects the appropriate ISO setting depending upon the conditions you’re shooting in (it will try to keep it as low as possible) but most cameras also give you the opportunity to select your own ISO also.
When you do override your camera and choose a specific ISO you’ll notice that it impacts the aperture and shutter speed needed for a well exposed shot. For example – if you bumped your ISO up from 100 to 400 you’ll notice that you can shoot at higher shutter speeds and/or smaller apertures.
Questions to Ask When Choosing ISO When choosing the ISO setting I generally ask myself the following four questions:
Situations where you might need to push ISO to higher settings include:
Most people tend to keep their digital cameras in ‘Auto Mode’ where the camera selects the appropriate ISO setting depending upon the conditions you’re shooting in (it will try to keep it as low as possible) but most cameras also give you the opportunity to select your own ISO also.
When you do override your camera and choose a specific ISO you’ll notice that it impacts the aperture and shutter speed needed for a well exposed shot. For example – if you bumped your ISO up from 100 to 400 you’ll notice that you can shoot at higher shutter speeds and/or smaller apertures.
Questions to Ask When Choosing ISO When choosing the ISO setting I generally ask myself the following four questions:
- Light – Is the subject well lit?
- Grain – Do I want a grainy shot or one without noise?
- Tripod – Am I using a tripod?
- Moving Subject – Is my subject moving or stationary?
Situations where you might need to push ISO to higher settings include:
- Indoor Sports Events – where your subject is moving fast yet you may have limited light available.
- Concerts – also low in light and often ‘no-flash’ zones
- Art Galleries, Churches etc- many galleries have rules against using a flash and of course being indoors are not well lit.
- Birthday Parties – blowing out the candles in a dark room can give you a nice moody shot which would be ruined by a bright flash. Increasing the ISO can help capture the scene.