As much as we like to think photography is a pure art form, we do still have to consider basic physics when we create images. One major sticking point is that when you close in on a subject, there’s something that happens all the time in macro photography: the depth of field becomes increasingly shallower. Normally, a couple of stops down on the aperture can solve this problem but, at extremely close ranges, you can’t always get exactly what you want and you must contend with issues like diffraction if you keep pushing your aperture ever more closed. This is where focus stacking can save the day, because it lets you create images with deep depth of field without many of the downsides of conventional shooting. Thanks to modern cameras and image-editing software, it hasn’t been easier.
So how do you do it?
Shooting
The process of focus stacking starts during shooting. If you mess up here it can make things a lot more difficult, if not impossible, later. It isn’t that problematic, however, because the essential equipment is still just a camera and a tripod—make it an extra sturdy tripod, if possible. From here on you will want to set up your shot as normal, since the actual focus stacking process doesn’t begin until you are ready to hit the shutter.
Let’s go over some shooting tips that will help make this process as seamless as possible. First, you are going to want to be shooting in manual, because focus stacking involves taking multiple images in a row and then blending them. The closest you can get the images to match in the capture stage, the easier the editing will be. Second, manual focus is almost required, unless you are using a camera with a built-in focus-stacking function, such as the Nikon D850 I used for this article, which can be set to do all the hard parts for you by automatically shifting focus and capturing a series of images based on your parameters.
When working with your camera’s settings, generally there aren’t any huge rules, though stopping down a bit can help because it means you will be likely hitting the sweet spot of performance for your lens and have slightly deeper depth of field, which will result in smoother blurring and, potentially, a need for fewer photos.
Once all that is sorted out, the process is simple. Working from front to back, or vice versa, you take an image of where you want the plane of focus to start and keep adjusting the focus for each shot thereafter, until you reach where you want the focus to end. This can mean as few as three images or even up to hundreds, depending on how precise you need the final product to appear and how shallow your depth of field is during capture.
Now that you have the raw files, it’s time to jump into the meat of this tutorial.
Editing
There are a few pieces of software that can handle focus stacking, but here I am going to stick with one of the most common options: Adobe Photoshop CC, which is available in the Creative Cloud Photography Plan.
Step 1: Using either Bridge/Camera Raw, my preferred option, or Lightroom, find all the raw images you will use to create the final photograph. Select them all and make sure that any changes to exposure, shadows, highlights, etc. are made universally across each image. Basically, here is where you make some initial changes and ensure everything matches for easier blending later.
Step 2: With all your images now selected in Bridge or Lightroom, you are ready to go to Photoshop, and there is a fun trick that makes it super easy to pull them all in as layers in a single document. For Bridge, this is found in Tools > Photoshop > Load Files into Photoshop Layers. In Lightroom, it is under Photo > Edit In > Open as Layers in Photoshop.
Step 3: Now that the hard part is done, there are a couple of tools to get the effect we are after. First, use Photoshop’s Auto-Align Layers tools set to Auto to make sure everything is lined up. The reason for this is because things like focus breathing can result in the sequence of images not being perfectly matched. Second, you will use the Auto-Blend Layers tool with Stack Images and Seamless Tones and Color selected to create a complete image.
Step 4: Ta-da! After a short processing time, you should now have something very close to your final image. It is possible certain layers didn’t blend perfectly and some manual masking or editing may be needed, or that you need to crop out some of the edges, but you are so close to the finish line as long as you followed the earlier instructions.
Step 5: From here you can crop down to your final image and make any standard edits and adjustments you need. Then export it to whatever format you would like to share online or make a print.
Being careful and organized is critical for focus stacking and, with a little bit of practice, you should be able to add this tool to your repertoire easily. It may not be needed all the time, but for the moments it is useful it can be a real lifesaver, allowing you to create a difficult shot without compromising on image quality.
Click here to learn more about Macro Photography. Do you have any of your own tips for pulling off the perfect stack? Any questions? Please feel free to leave a comment below!
