Don’t waste time juggling the ISO between shots! In this tutorial we show you why Auto ISO can work in your favour when light levels are low and unpredictable.
Normally you need to treat automatic modes on digital SLRs with caution. You’re trusting a machine to make better decisions than you would, and there will be lots of situations where the only way to get great shots is to take control yourself.
However, there is one automated option where the camera really can do the work for you. Auto ISO is designed for conditions where the light levels are low and unpredictable. You want to be able to shoot at the minimum ISO possible but without using dangerously slow shutter speeds.
These settings are just a simple bit of arithmetic. You’re not asking your camera to use its own judgement, which is where most automatic modes cause problems. It does what you would have done anyway, as you’ll see…
How to use Auto ISO effectively
01 Know your limits
Start by opening the Shooting menu and then the ISO sensitivity settings. On this screen, set the Auto ISO sensitivity control to On, then set the maximum ISO and minimum shutter speed you want the camera to use – you can judge these according to the situation you’re in.
02 Get shooting
Now see what happens when you shoot. We’re shooting in the Guildhall Market in Bath, which is under cover. Our camera has selected the lowest ISO it can (ISO640 for this particular shot) in order to achieve our minimum acceptable shutter speed of 1/60 sec.
03 Give your camera a hand
The lower your minimum shutter speed, the more leeway you’ll give the camera with the ISO setting. If you are shooting at 1/60 sec, switch on the lens’s image stabilization, if available, and brace the camera against walls, tables or doorways where possible to reduce blurring.
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What’s the highest ISO I should use? Find the answer here