I recently picked up a true 1:1 macro lens, the Lester A. Dine 105mm 2.8, and have been experimenting with it endlessly. One thing I discovered about macro photography is that the depth of field is exceptionally shallow, even at the largest (smallest) aperture. This is exacerbated if you’re using extension tubes to get larger than 1:1 reproduction.
One way to combat this limitation (if you view it as such) is through a technique called focus stacking. Like HDR photography, multiple exposures are combined using software (in my case, Adobe Photoshop CS5) to create the final image.
The camera setup for my example was pretty simple. I used a set of Zeikos extension tubes to get closer to my subject, my fiance’s engagement ring, and shot with a tripod and remote shutter release.
I tried a few flash setups, but couldn’t get the lighting I wanted, so I ended up balancing my continuous ring light above the ring. All of that was sitting on top of a large piece of Plexiglas.
Once I had the lighting and orientation the way I wanted, it was time to start shooting!
With focus stacking, all you need to do is choose your desired aperture, white balance, and other exposure settings (none of these should change during shooting), focus on part of your subject (starting at either the front or the back) and shoot away. Between shots, adjust your focus slowly through the whole subject. The total number of shots you’ll need depends, of course, on your subject and the aperture you’ve chosen. For my example, I shot 22 “slices,” but only ended up using 21 in my stack (the last shot left too much of the entire subject out-of-focus and ended up being detrimental to the process).
I imported the individual photos into Adobe Lightroom 4 and adjusted the white balance on all of them before exporting to Photoshop. Selecting the shots you want to use, right-click and go to Edit in -> Open as layers in Photoshop.
Once all of your slices are loaded in Photoshop as layers, select all of them, go to Edit and Auto-Align Layers. I usually leave it set to Auto, though this time around I did click the Geometric Distortion option. It may be trial and error depending on your subject. When I ran it the first time without the geometric distortion correction, Photoshop couldn’t line up all the pieces correctly.
After that’s done (which may take some time depending on your system limitations), go back to Edit and Auto-Blend Layers. For those who don’t know, this is also where you’d go in order to create a seamless panoramic image in Photoshop. If things aligned correctly, Photoshop should be smart enough to know you’re stacking and already have Stack Images selected. By default, the Seamless Tones and Colors option is checked (and may also involve a bit of trial and error). I unchecked this option after my first run through ended up with some funky color changes. The second comp resulted in a much more natural looking image.
The resulting comp probably won’t always need as much cleanup work as mine, but I have a feeling the extension tubes had something to do with it. Since all of the images are stacked and masked in Photoshop, it’s relatively simple to go through and pick and choose which things to keep and which to mask out. This is exponentially harder to do if you have the Seamless Tone and Color option checked.
Here’s the final image after cleaning it up in Photoshop and doing some basic Lightroom edits. The resulting image shows much more focus and detail than I would’ve been able to get with a single exposure. It can be a time-intensive process, but can give you some extraordinary macro results. And like really good HDR, you’ll know you’ve done a good job when it’s not immediately evident that anything was done at all.