How to measure the dynamic range
To get the right exposure, you need to know the brightness range you’re dealing with. Here’s how to do it.
Switch to manual
In M mode you can note down the exposure readings and choose how you interpet them, rather than relying on the camera’s ideas about correct exposure.
Choose an aperture
If you select a specific aperture, you only need to change one variable – the shutter speed – to work out the best exposure. Let’s go for f/8.
Swap to spot
Now select the spot metering mode. This takes an exposure reading from a small area around the selected focus point only – so switch to single-point AF mode.