I have recently been trapped inside the house by the weather during Christmas break, but I still wanted to play with my camera. So, I have been resorting to setting up things in the house to photo, as in my full frame/APS-C sensor comparison blog.
Today, I decided to experiment with focus-stacking using Photoshop. I have messed with this before, but not really had a practical use for it. So, I decided that I would practice a bit just in case it became handy in the future.
The scene: a bunch of Santas and nutcrackers that my girlfriend decorated with. In the two photos below, you can see that in one photo the items in the far-ground are in focus while the foreground Santa is out of focus. And when the foreground Santa is in focus, the far-ground items are out of focus. This was all shot at f/8 and stopping down the lens further wasn’t going to help that much.
So, I ended up taking seven photos, manually focusing on varying depths into the scene. My first trial didn’t go well as I didn’t maintain a constant exposure and I relied on auto-focus. With camera metering, some of the exposure levels were based on Santa and some on the bright window in the background. Switching to manual mode and manual focus, I got much better results.
Next, I imported the seven raw images into Photoshop as layers, then I had to rasterize each image, then align them, and then use the Auto-blend layers function. The auto-align corrects for the distortion from each focus setting so you lose a bit of the edges.
Below is a screen cap showing how Photoshop masked the data in one of the images for the final blend. Note also that the corners are gone as it corrected for distortion between images.
Next, I exported the final merge to a TIFF and went to Lightroom to make further adjustments. I had to crop out the rough edges, and warm up the scene a bit. And as you can see, all of the Santa and Nutcracker faces are in focus. Even that elf on the clock in the back is in focus. The blend did kind of make a mess with the blinds in the background, but I didn’t make any images with them in focus.
So, for taking a series of images for focus-stacking some key points are:
- Maintain exposure. This will probably require you to shoot in manual mode unless you want to hold the exposure lock button the entire time.
- Use a tripod so that the images line up well.
- You may have to resort to manual focusing, as even with single-point autofocus the camera may not accurately focus on what you want.
Other than that, the Photoshop process is very simple. Thanks for reading, please leave comments below.
2 thoughts on “Focus Stacking”
A friend of mine took some macro images of peppercorns using a similar technique but he used a focussing rail. I think that he ended up needing about 12 shots to get everything in focus.
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I have set this up to practice a couple of times now because it seems like it would eventually be useful in taking landscape photos, but I have never used this technique in practice. I will try to look for an opportunity in the wild.