Post-Processing: Focus Stacking
Next up, we're gonna do some focus stacking. So, we've already talked about focus stacking in-camera with Olympus's in-camera focus stacking, but we can also stack photos after we shoot on the computer, and we have a couple of options to do that. We can do that with Photoshop or we can do that with software that's dedicated to focus stacking like Zerene Stacker or Helicon Focus. What we're looking to achieve is something like this where everything that we want in focus is in focus, and everything that we don't want in focus is out of focus. This allows us to create results that aren't always possible with a single shot in-camera. So, the first thing we need to do is bring some photos into Lightroom. I've already pre-selected three photos to work with my stack. These photos were intentionally shot, focusing on different areas of my subject, and you'll see what I mean in just a second. None of these photos are ideal on their own, but when we stack them together, we're gonna get a really ...
cool result. So here, Photo 1, the front of the eyes are not in focus. This photo would be considered a miss. Next, we almost have the front of the eyes in focus. The focus is a little bit closer to me, but not the front of the eyes, also a miss. The third photo has the front of the eyes in focus, but now the back of the eyes are out of focus. And what I want is the front of the eyes, the face, the back of the eyes, all in focus. But I want to keep this nice soft background around the subject, and because we have these three overlapping focus areas, we can merge these together in post and create a stack that's all in focus the way we want it. So, the first thing that I like to do when I'm preparing photos for a stack is set myself up for success. Stacking software, whether it's Photoshop or something else, have the ability to auto-align your layers and auto-align areas, but it's even better if we can help it out. So, the first step is going to be to help that out. We're gonna go in and develop our photos, and we can pick any one. So I'm gonna pick the third shot because that's the closest to the result that I want, and the first thing I'm going to do is crop. So we'll crop it to a 4 x 5 ratio, and we're gonna crop vertically, and make sure you leave a little bit of area above and below the subject because I shot this handheld, and we need to compensate for my movement. So as I'm adjusting my focus in or out, I'm moving ever so slightly. I'm doing everything I can to stay perfectly still, but inevitably, there's some movement. So, as you can see, before I even crop from 1 to 2 to 3, these photos are not perfectly the same. And, we're gonna try and straighten that out before we go into our stacking software. So, back to that crop, we'll go to 4 x 5 portrait. Give a little bit of buffer above and below, like this, and what I like to do is find reference points in my crop because what I want to do is crop these three images the exact same way as one another. So, here I have this intersection at the right edge of the eyeball, or of the eye, and I'm going to use that as a reference point when I crop my other images. Like this, and then I can go through and make my other adjustments. Fortunately, this image doesn't need all that much work, but I'll make a couple of quick adjustments to push it where I want it. So slight exposure adjustment, some more contrast, I'm gonna bring up the highlights to lighten that green in the background, just a bit of texture. I really like this purple wave through the eye. I'm gonna come in here, and I'm gonna adjust the saturation to the purple and bring it up a bit here in luminance. And then we're gonna reduce noise outside of the face of the fly. We'll do that the same way we did with the Crane Fly. We draw an area that we don't want to impact with noise reduction, invert that area, and reduce the noise. And you'll see here again, just like with the Crane Fly, here's a lot of noise reduction, here's negative noise reduction, and here's in the middle. So, it's not particularly noisy, especially when we're zoomed in this far, but it is more appealing if we smooth it out. So here's what we've got. Now what's great in Lightroom is you can apply these settings to multiple photos. So this is the only photo that I have to process. With the other two photos in my stack, I'm just gonna get them aligned to the base photo, which is this one. So I'm going to copy my settings, I want to make sure that I'm including crop. I didn't do any spot removal, but I wouldn't want to keep it anyway. So we copy the settings. We go to the next photo, paste, next photo, paste, and we have three images that are processed identically and cropped the same. But we still have some movement to account for, and again, we can rely on our software to align them, but I like to get them as close as possible before I go there. So all we have to do is move the fly to our best guess using that reference point that I mentioned for each of the three photos. So now we'll be much closer to aligned. And that gives us a much better chance to have a successful stack. So now we're ready to export our photos. We select the three photos we want to export, right click, choose Export, find our location, I already have that location chosen, make sure that our quality's a hundred percent, and export those three photos. When it's time to bring those photos from Lightroom into Photoshop to do your stack, all you have to do is choose File>Script>Load Files Into Stack. You browse for your images and choose the photos that you'd like to focus stack. Before hitting Ok, make sure you click Attempt to Automatically Align Source Images. We've already aligned them somewhat, but this will go the rest of the way and finalize the alignment. You'll see Photoshop bring your images in as three individual layers that you can work with individually if you need to. Once those images are loaded, select the layers that you want to stack, go to Edit, Auto-Blend Layers, choose Stack Images, and your stack begins. One really nice thing about stacking in Photoshop is the fact that it saves your layers, and it doesn't destroy anything, meaning, you'll end up with three layers that have masks, so if there's an area that didn't quite blend perfectly or that you don't like the results or you want to make a change, you can go back into those layers, adjust the masks or the contents of the masks and revise the results. And now our stack is complete. Photoshop automatically fills in the edges using Content Aware Fill, and we have the result that we wanted. So, unlike any of the three source images, everything that we wanted in focus is in focus, from the front plane of the fly's face, all the way to the back of the eyes and up behind the eyes. As I mentioned, you'll have three layers with masks merging together the in-focus areas, and a new layer with the stack. All of the areas we want in focus are in focus, from the front of the face all the way to the back of the eyes and just beyond. To save this image, simply save it like you would any other image in Photoshop, and we'll save it as a JPEG, and that's it. The best way to focus stack on your computer is with dedicated focus stacking software, so now I'm gonna take those same fly images and stack them using Helicon Focus, which is a dedicated stacking program. We open Helicon Focus, and all you have to do is drag your source images into the window. Here's those same three images we just stacked in Photoshop. We drag them in, you can see it works very quickly, and we have our three source images. With Helicon Focus, you have three rendering method options. You have Method A, which produces smooth transitions and preserves color. Method B, which is the depth map. That works best for continuous surfaces, and Method C, which is good for intersecting objects and deep stacks. Since we have a shallow stack that is not a smooth surface, we're going to use Method A. You can zoom in to see the details here, and all we have to do is click the Play button to render, and our stack is complete. It's that easy. So if we zoom in over here, we can see nice and clean and on the left we have our source images, and we can look at one image at a time. So, Image 1, 2, or 3 will display on the left. And if you're happy with the results, our stack is complete. If you aren't completely happy with the results, you can re-render using Method B or C or you can even retouch the image to bring in areas from a source image. For instance, if I wanted to use source image for this area of the fly's leg, all I have to do is take my brush and brush over that area and now that area from the source image I've chosen comes into my result. When you're happy with the result, all you need to do is right click on the thumbnail, say Save, choose your destination and name, image quality, and you're all done.