How to Focus stack in Photoshop CS4

Photoshop is full of clever, cool little tricks that it can take quite some time to fully experience them all. One of the cleverest tricks comes in the Photoshop CS4 and allows you to combine different images of the same object and combine the areas of sharpness. By doing that you would be creating a focus stack and increasing the depth of the field in the photo. So sit back and find out how to create a focus stack using Photoshop. Enjoy!