What is Focus Stacking?

JGaulard

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If you're a macro photographer, you need to know what focus stacking is. You don't even need to be a very experienced macro photographer or one who wants to learn every last detail there is to know about this type of photography. The reason you can be a newbie is because what I'm about to explain is a simple concept to understand and to execute. As long as you have a copy of Adobe Photoshop installed on your computer and a camera in hand, you'll be fine.

Okay, here's what focus stacking is. It consists of taking a few different photos of the same object from the same position, but with a focus on different elements of that object. So for instance, let's say you took three photos of a flower. You'd first focus on the front petals and then, after that, you'd focus on the center of the flower and then finally, you'd focus on the rear petals. If you've ever photographed flowers before, you know that the depth of field can sometimes be shallow with these close up types of images. The three different shots of the same flower with a focus on varying parts of that is part of an effort to get around that obstacle. For a very thorough description of focus stacking, please read my previous post on the topic.

Anyway, please allow me to continue. After you take the three images with different focal distances, you can process those pictures in a photo editing application such as Adobe Photoshop to actually "stack" them. Photoshop will analyze each image and will find the sharpest area of the photos. Then, it will combine the first sharp area with the second and third sharp areas and will create an entirely new image that's sharp from front to back. This technique is extraordinarily helpful when it comes to, like I said, macro and up close photography because those types are famous for having very shallow depths of field because of their proximity to their subjects. Even if you use a very small aperture, you'll still end up with a shallow depth of field in these cases.

To accomplish something like this in Photoshop, you'll first need to import your images as layers in the same file. This is called loading files into a stack. Once you have the images in a file as layers, you'll need to go ahead and select all of them in the Layers panel. After that, you'll go to the Edit > Auto-Blend Layers menu item and click. This will open up the Auto-Blend Layers dialog. Go ahead and select the Stack Images option and then be sure to check the boxes for the next two options below that one. Click OK and you're done. Photoshop will process the images and will give you a final photo with a much deeper depth of field than you'd ever be able to capture with just your camera and lens alone. That's really all there is to it.

After reading through what I just wrote, I think I'll sum things up by saying that "focus stacking" is the process of stacking your images on top of one another. It's then the process of keeping the areas of each image that are sharp and discarding the areas that are blurry. You need to capture the appropriate images and Photoshop will do all the processing after that.

Do you have any further advice for when it comes to focus stacking? Do you have any questions about this process? If so, please share below. Thanks!
 
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