Focus Stacking is a technique that is very popular, if not essential in macro photography. You take several photos and relatively low apertures, while shifting the focus of the lens from the closest point of the subject, to the furthest, then stack them in post processing software, so that that you have an image that is completely sharp from front to back.
So why would you want to use focus stacking instead of an aperture like f/11 or f/16? Well, there are times when you may have a subject really close to your lens that you want in focus, as well as something in the background. Now sometimes getting everything sharp is physically impossible, like in this photo here.
Mud Cracks in Death Valley
Now if you tried to use a small aperture, like f/18 or f/22, 2 things will happen. One, you still would never be able to get all of the scene completely sharp. It just isn’t possible. Physics, amirite? Secondly, using an aperture that small will cause the image to get soft, or lose sharpness on the edges of the frame. Thats just a product of letting light into a small hole in the lens.
So the solution to these problems is Focus Stacking. My technique for this is quite simple. Once I have composed my image and determine that I need to focus stack, I take a few steps. First, I focus on the closest point of my subject. Now I prefer manual focus using the back LCD screen on my camera, as I find it is more accurate that way. You can use autofocus as well, or if you have a mirrorless camera or Nikon d850, you can also use the focus peaking feature. I then take 3-6 shots at an aperture of anywhere from f/5.6 to f/8. Each shot I move the focus point back a little and take the next shot.
Once I’ve taken all the shots I think I need, I’ll bring them into Lightroom and Photoshop for post processing. I usually do just some basic adjustments in Lightroom to white balance, sharpening, contrast etc. Once I've done that to the first image, I will sync the other images to the edited one.
Next, with all of the images still selected, I will right click, select “Edit In” and then “Open Layers In Photoshop.”
Once in Photoshop, I make sure all the layers are once again selected. I go up to “edit” then select “auto-align layers.” This will align all the layers so that there is no ghosting during the blending process.
Next, with the layers still selected, I go to “Edit” then “Auto-Blend Layers” This is allowing Photoshop to actually stack and blend the images together.
Once the image is done, just crop it to your liking, and you’re set! Just make sure to double check the image to make sure everything was blended properly. Photoshop normally does a really good job and I usually don’t have any blurry issues. You can see the masks here which shows what Photoshop did to blend certain parts of each image that was sharp.
From here you just continue on with your own workflow with post processing. Thank you for reading this tutorial and if you’re interested in watching this in video form, it is up on my YouTube channel! Just click the link at the top of my homepage to check out my channel and make sure to subscribe for lots of tutorials and behind the scenes videos.