Article

How to set and use PRE

If you have not already done so, read the page on white balance settings   first.

The PRE setting is used:-

• where we want the most accurate colours.
• where there are strong dominant colours in our scene.
• in difficult situations, like mixed lighting.
• where we don't know what other setting would work well.

We could use PRE all the time but the extra work involved cannot be justified for a lot of the more general shots. We can set PRE either using the WB setting on the camera body or from the menu choice. See white balance settings Details on setting a PRE by measuring the light is below. When we go to PRE it's set at the last PRE reading we set it at, and some cameras have the ability to have up to 5 PRE settings and to switch between them. From the menu you can, with some models, go onto the PRE setting and copy a PRE to a storage slot where you label it for future use, or select a PRE from another photo see below. Use the PRE menu choice to use a PRE you have previously set. From the camera body select PRE and then with the sub command you can select with some models the PRE you have set.

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We can set the PRE either by measuring the colour of the light or to be the same as the white balance setting of another shot.

Setting PRE from another shot

• go into the menu option for PRE and set it based on another photograph and select the photo.

Setting the PRE based on the colour of the light

• See below.

Setting PRE by measuring the colour of the light

You can do this from either the menus or from the camera controls, but let's look at the way with the camera controls, the menu route is the same process but following menu choices.

Select PRE with WB (see white balance settings if you don't know how to do this).

1. Press WB and then press and hold down WB until PRE flashes.
2. While PRE is flashing point the camera at a grey card or target and press the button as if taking a photograph.
3. The camera will show either "GOOD" On "No Gd".

• If GOOD you have recorded the PRE which is in PRE setting space 0.
• If No Gd, it didn't work, maybe you didn't have the grey card covering the whole image, try again.
• Nothing showing - you took too long and the PRE stopped flashing before you pressed the shutter and instead you took a photo of the grey card.

From menu settings you can do the same.

PRE is a very powerful tool with far more capability than we have illustrated here, it can be used with false grey targets to introduce deliberate biases, for example to warm up the images, and in combination with other target systems, see Other steps we can take on white balance.