Everything You Need to Know About Focus Stacking

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Nowadays it’s becoming harder, and harder to get the entire image sharp with the constantly wider lenses and more extreme foregrounds that are used in photos. Even great apertures aren’t enough to get both foreground and background in focus, or as sharp as you would desire them to be. Although hard, this is not impossible. Focus stacking for sharper images has become a go-to technique for photographers of all levels to achieve images that are sharp throughout the entire frame, front and back.

Focus stacking is a technique that combines the use of a camera and a post-processing software to merge multiple photos. Focus stacking is commonly used in various forms of photography but is most known within landscape. macro and wildlife genres. The technique involves capturing two or more images with different focus lengths throughout the scene. Later one, these images are brought together using the sharpest areas of each image to create one crisp photo. The result is an image that has a sharp foreground, middle ground and background.

There are quite a few benefits to this technique, but it takes a little longer in the field, and in post-production. As mentioned above, images won’t be sharp all the way through if you use a wide angle lens and place a subject close to it in the foreground. When there is such a large distance between the foreground element and the background, only parts of the images you shoot will be usable. By capturing multiple images with different focus points throughout the frame, the final image will be sharp all the way.

In macro photography, which I am no expert on, getting the entire flower or insect sharp is often a hassle. Zooming in so close for those shots will surely put something else in your frame out of focus. This is where the stacked image technique comes in handy. Just capture the subject your focusing on, using multiple images, and blend them together to create a macro shot that has the entire rose in focus.

Focus stacking might be a nice tool to have handy when you need it, but the time and effort spent isn’t always necessary. Most of the time, having soft areas in your photos just adds to the appeal of the image. The technique is only beneficial us certain scenarios, most of which were already mentioned above. Some may include:

  • Photographing a scene with great distance between the foreground and background.
    Using an ultra wide angle lens and there’s a subject close to it.
  • Zooming in on a scene, such as a forest, and you want everything to be sharp even with an open aperture.
  • Photographing small scenes and macro photography in general.
  • Or if you don’t have a macro lens, but want to zoom in using a normal lens to make it look like a macro shot. Stacking helps create this final look also.

A good practice is to capture a test shot with the optimal aperture such as f/11 and zoom in to see if everything is sharp. If the foreground subject or distant mountain is visibly soft and slightly out of focus, that’s a good indication that a stacked focus image should be used.

So all of this sounds dandy but how does it actually work? Even though it’s an advanced technique, it’s actually not as difficult as you might fear. Capturing multiple images with different focus points is rather easy and if you’re already familiar with blending multiple exposures for better dynamic range this won’t be that hard.

If you’re new to Adobe Photoshop this might be confusing and even demotivating but, trust me, with some practice it won’t be long until you master the art of focus stacking (and so much more!).

Part 1: Capture Multiple Images In the Field

Now that we know what focus stacking is, why you should use it and when it is beneficial, let’s look at how it’s done. As I mentioned this is a two-step technique where the part one takes place in the field.

Start by setting up your image just like you would normally do. Find the composition and perspective you prefer and set the ISO, shutter speed, and aperture.

While it’s not essential, it’s highly recommended to use a tripod for this technique. Since you will capture multiple images of the same scene, a tripod ensures that the camera stands still so the images will be the same – this is important when we blend them together in Photoshop later on.

Adjust the Focus

After finding the composition and adjusting the settings, change the focus point to the object nearest your lens. This can be done by using either manual focus or automatic focus or both.

Take the first image when the camera has focused on the nearby object. When the image is taken, adjust the focus point to be slightly further away, for example, in the middle ground. Repeat the process and then move the focus point even further away.

How many images you need depends on the individual image. In most cases two or three images are sufficient. However, some images require twice as many shots to get the entire image sharp.

If you’re unsure how many images you need to capture, simply look at those you’ve already got and check if everything is sharp if they were to be combined. If you’re still unsure take a couple images extra with different focus points, just in case.

That’s it! The first part of this technique is not that difficult and after doing it a couple times you’ll quickly see how many shots a specific image requires.

Let’s quickly recap how to focus stack:

  1. Find your composition like you normally would do.
  2. A tripod is beneficial but not essential.
  3. Focus on the object closest to the lens and take an image
  4. Adjust the focus to be further away (how much depends on the distance between the foreground and background) and take another shot.
  5. Repeat step number 4 until you’ve got enough images to make the entire image sharp.

Part 2: Focus Stacking Post-Processing Technique

Now that you’ve captured multiple images with different focus points it’s time to head back to the computer and blend them together.

The following steps might be a little confusing for those who don’t have much experience in post-processing software but by following these instructions step by step the result will be one razor-sharp image.

Adobe Photoshop is the most used software for advanced image processing. Experienced users can achieve endless techniques and effects in this software and it’s considered by many landscape photographers to be an essential tool.

The Photoshop algorithm will analyze each individual pixel and select only the sharpest one from each image before it creates a merged file.

Focus Stacking in Adobe Photoshop Step-by-Step:

  1. Open the images as Layers in Photoshop (If you use Lightroom select all images and chose Edit in… -> Open as Layers in Photoshop
  2. With all layers selected go to Edit -> Auto Align Layers
  3. Duplicate all layers (this might come in handy later)
  4. With only the duplicates (or only originals) selected go to Edit -> Auto Blend Layers. Select Stacking Images and check the box for SeamlessTones and Colors.
  5. Photoshop is now automatically blending the image.
  6. Zoom in 100% and check if every area is sharp
  7. If there are areas that are unsharp, create a merged layer with a white layer mask and move one of the unedited layers beneath it. With a black brush paint the sharp image back in.

It got a little confusing there at the end, right? That’s ok. In most cases you don’t actually need to use the duplicated layers but every now and then you do.

Helicon Focus us another software that many photographers use, but I will be honest and tell you right away that I do not have any experience with Helicon Focus.

If you’d like a recap on Aperture, take a look at “Open Wide! A Look At Aperture” here.

 

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