Focus Stacking is very popular with people who specialize in macro photography. The simple reason being the knife edge depth of the field on many macro lenses.  A 105mm macro lens with an f-stop of 40 might have a depth of field of 0.25 inches. That is under ideal conditions. This makes for some serious problems when you are taking an image of an object of irregular shape or much larger size.

Focus stacking is one of the more technical aspects of Adobe Photoshop. It takes a bit of planning, a bit of money, and some experience. I have suffered my share of failures in getting this skill set into my tool box, so don’t be upset if the first few tries don’t work out for you.

The technique of focus stacking begins in the camera.  The first thing you are going to need is a proper macro lens. Macro lenses are rather specialized, though they can be used for both macro and portrait photography with a bokeh effect. For shooting,  I use a Nikkor 105mm micro lens. I decided on a 105mm as my research indicated that shorter focal length lenses had a tendency to cast shadows in some images. A second reason is magnification; I could be further from the object. Some of the short focal length lenses have you nearly up against the target to get a proper photo.  I could be several inches away and still get a clear, crisp shot.

There are also auto focus macro extension tube sets that can be added to telephoto lens sets, but I have found they don’t really deliver. I am a high detail kind of photographer and telephoto lenses already have a number of glass elements to overcome for a clear, detailed image. Adding an additional piece of glass of dubious quality is not going to be the same as a dedicated macro lens.

Next is a good sturdy tripod. I’m not made of money so I had to be very careful about which tripod I added to my photography kit. I have found that you pretty much get what you pay for when it comes to tripods. The one you can get at Target for $75 is not as versatile as a Vanguard tripod and head combination. Find one that meets your needs. I went with a carbon fiber tripod with a ball head and never looked back. It has been around the world a few times and occupies that sweet spot between cost, weight, size and need.

An optional, though highly recommended, tool for macro photography and focus stacking is a macro focusing rail. Before I purchased one of these handy tools, my success rate was not as good as I would have preferred. When your depth of field is about 1/16th of an inch, trying to find the next focus point without this can be difficult in the best of circumstances, if not outright impossible. With this tool, you do not change your focus point in the camera, you move the entire camera and with it, the focus point is moved in increments. I have a success rate of around 95% with a focusing rail.

A remote trigger is a good idea to have around for many reasons and would be an excellent tool in speeding up the process. If you do not have one, I recommend using the camera timer to avoid shaking and vibration during exposure.

So okay, you have the equipment. Now here are a few points from my experiences in macro photography. First thing to do is turn off any long exposure noise reduction. I am not a big fan of noise, but not exactly happy with noise reduction and its effects on the clarity of my photos. With long exposure noise reduction in macro photography, it is twice as bad. You could get the same effect with a telephoto lens and some heavy cropping.

You will need to shoot in manual mode. Set your ISO to the lowest possible setting i.e. 100 in most cases, then make sure your white balance is set to match your lighting. Focus can be affected by a bad white balance.  This will insure that all the photos will have the same properties, outside of the changing focus point.

For this exercise, I grabbed an old coin out of the drawer. I laid it on a sheet of white stock paper and focused a single light source on the subject. This will add contrast, which, in my experience, adds to my success rate. Then I started taking photos using the focus rail to move the focus point from the top to the bottom of the coin.

My camera was set to f-40 and a shutter speed of 1/1.3. This gave me a depth of field of about 1/4 of an inch. Using the focus rail, I moved the camera about 1/5 of an inch per photograph. This gave me some focal overlap with each image. As you can see in the above gallery, the focus point moves from the bottom to the top of the coin. The yellow tape measure is an attempt to show where the focus point is at any point.

Now we open all the images in Photoshop. First thing you should do is inspect the images to make sure they are clear, but avoid any editing of the individual images. Wait for after you have merged them into one file.

From there, go to File>Scripts>Load files into Stacks, and add open images into the file field. You will notice a box that asks if Photoshop should attempt to align the images; you should check this and let it do its job.

As you can see, Photoshop has created a single document with five layers. If any of your images were out of place, Photoshop went the extra mile and aligned them to the others. This is not unheard of, and if you have been using a focus rail, chance are they were slightly off. Now, if everything is good, time for the real work to begin.

Under Edit, you will find Auto-Blend Layers… Go ahead and give that a tap and tell the dialog box to work with the stack Images and make sure Seamless Tones and Colors is checked. This is going to take some horsepower. The more images you have taken, the longer it is going to take. We are not talking hours, but there is a lot of computations going on, so sit back for a minute or so.

If all went right, you should see a single well-focused image. If you look at the layers menu, you can click on the layers and see what Photoshop used and what it discarded. I’ve tried to make head or tails of why it made certain decisions, but it make no sense to argue with success.

Now you can flatten the image and do any editing you might feel is necessary. My final image needed a slight bit of Smart Sharpening, but not much else.

Now, focus stacking is not just for macro photography. Case and point is the title images above. For these photos, I used a 50mm lens and a tripod. No focus rail this time. It was actually easier as my depth of field was much wider and had more overlap.

The techniques is effectively the same, just a different subject. The end product is a full-focused image and, with a bit of editing and a nice vignette for drama, a nice image.