Focus Stacking FAQs: Software, Equipment & More (Digital Photography)
What Is Focus Stacking?
Almost every photograph has a part that’s in good focus, and one or more parts not. The part in focus is the depth of field for this shot. Several factors can influence depth of field, including distance to the subject, aperture and focal length of the lens. In many landscape shots, the depth of field—the area in good focus—can be many yards wide, while in some close-ups it may be only a couple millimeters or less.
How to Focus Stack
- Keep the F-Stop Close to the "Sweet Spot": Most if not all lenses have a “sweet spot”, an aperture setting that gives the best quality photos. For my Nikon lenses, it is usually between f8 and f11. Many people believe that by increasing their f-stop numbers, closing down the aperture opening of the lens to f22 or more, they can get a wider depth of field and more of the scene in focus. This is true to a point, but beyond that point the image will suffer because of “diffraction”, or light distortion. It’s always best to keep the f-stops as close to the sweet spot as possible. Therefore, focus stacking was invented.
- Use Software: Focus stacking doesn’t actually increase the depth of field for the lens, but merely the apparent depth of field in the output image. Several shots are taken while adjusting the in-focus area with each consecutive image. When the series is finished, the images are run through a good focus stacking software which extracts the well-focused parts of each and combines them into one completely focused image.
- Choose a Stationary Subject (Or Edit Out Any Movement): Focus stacking works best on subjects that are stationary. An insignificant movement is fine with outdoor scenes or landscapes, but the less movement the better. There are ways to edit out movement in the output image of some stacked photos, and most good software programs have excellent alignment capabilities. There are some fine tutorials on YouTube.
What Equipment Do You Need to Stack Photos?
To stack photos, you will need a few items. Here is my “short list”. Though there are a few other gadgets that make it a little more convenient, they’re not necessary.
- DSLR camera: A good DSLR is a critical necessity. You might get by with other types of cameras, but you need a manual mode and a means to view the subject either through the lens or on a live screen. You must see the area of your subject that is in focus and move it as needed.
- Tripod: A sturdy tripod is necessary, especially for extreme close-ups.
- Remote shutter release: This isn’t a “must have”, but it comes in handy. Also, it cuts down on camera shake from tripping the shutter by hand.
- Computer: A computer is necessary to store your digital photos, and process the stacks with your preferred software.
- Good focus stacking software.
What Is the Best Focus Stacking Software?
In recent years, focus stacking has gained much popularity among amateur and professional photographers. But remember, a software program is not a magic wand that will always give excellent results. Results—good or bad—very much depend on the quality of the original images in the stack. If we take them in sufficient quantity for the subject, and focused with care, most of the focus stacking programs will give acceptable results.
Here are a few of the programs I have used, and an idea of how they worked for me.
Helicon Focus has become the de facto “gold standard” for focus stacking, and with good reason.
- Flawless: I own and have used several focus stacking softwares in the past decade. Some were very good—others not so much. Nearly all programs have their advantages and their faults. I have yet to find fault with Helicon Focus.
- Fast: Besides putting out an excellent product, Helicon Focus is FAST! It’s hard to believe that it can process an average stack of ten to twelve images within two to five seconds. Every other program I’ve tried needed several seconds to several minutes.
- Good Cost: Helicon is not free, but neither is it prohibitively expensive. The last time I checked, the Lite version was about thirty dollars for a year’s license, and the Lite version is all an average photographer will need. Also, they offer a lifetime license for a reasonable cost.
Zerene Stacker is considered by most (especially online) to be the main runner-up and competition to Helicon Focus. I downloaded the trial version to see how it worked for me.
- Disappointing Color: I processed the same images I had done with Helicon recently, and I was disappointed with the color rendition of the result.
- Several Artifacts: Also, there were several artifacts in the image, making it necessary to do some post-processing. This could have been because of bad input images, or my unfamiliarity with the program.
- High Cost: The primary thing, however, that I disliked about Zerene was the price: over one hundred dollars. Somewhat pricey considering the number of other excellent programs out there for much less or even free.
- Good Results: Photoshop does a splendid job of aligning and stacking images,
- Slow: Photoshop has a major drawback: It is SLOW. There are several steps to stack images in Photoshop, and it all must be done manually. You may spend five minutes doing the same job Helicon Focus would do in less than five seconds.
- High Cost: Another thing to consider with Photoshop: Unless you already have the program, you’re looking at a major investment.
- Okay Results: This program does an acceptable job of aligning and stacking the images.
- Disappointing Color: I was a little disappointed with Picolay’s color fidelity and saturation, as I was with Photoshop. Again, this could be because of operator error.
- Fast: It’s fast, but nothing comparable to Helicon.
- Free: Picolay is a small freeware stacking program with an unusual number of features.
Combine ZP is the latest freeware installment in a series that included Combine ZM and Combine Z5. In the past it was my “go to” program for stacking photos for more depth of field.
- Slow (But With Great DOF): Combine Z is a little slower than Picolay, but does a magnificent job of depth of field enhancement.
- Artifacts Along the Edges: There’s just one caveat: Combine Z has a tendency to leave artifacts along the bottom of the image or on one or both sides. We must trim most images, but this is not a major problem considering the exceptional quality of the output.
- Free: Combine ZP is free, not too complicated, and does a very acceptable job. Just be prepared for the inevitable artifacts.
Why Stack Photos?
Focus stacking can open up a whole new world of photographic creativity that you may never have dreamed possible.
1. Tack-Sharp Photos to Bring Out Details
Pictured below are an antique treadle sewing machine accessory and another vintage sewing machine attachment. By stacking several images, all parts of the gadget are in focus. Stacking the images brought out amazing detail. These were processed with Helicon Focus.
2. Online Auction Photos
Pictured below is a hand-crafted Navajo silver and turquoise cuff bracelet. I photographed this beautiful piece of vintage artwork for a listing on eBay. In the first photo of this stack, notice how only the very back of the bracelet is in good focus. In the last photo of the stack, the back is now blurry while the very front is the only part in focus. My aperture setting and distance from the subject did not allow me to take one photo with the entire piece sharp. Focus stacking let me get close enough.
Many times when we take a landscape photograph, we have to choose the part of most interest and focus there, leaving the foreground, background or both “soft” or blurry.
4. Inventory Collections
Pictured below are powder glass trade beads from the mid to late American fur trade era and Chinese glass “squash” or melon beads from the mid to late Manchu Dynasty. The first was processed with Combine ZP, and the second was processed with Helicon Focus.
5. Product Photos, Museum Photos and Business Reports
If you are contracted for this type of photo, you are dealing with professionals. And they WILL want their illustrations in tack-sharp focus. This is where focus stacking will stand head and shoulders above the competition.
How I Started Focus Stacking
It’s no secret that I’m an enormous fan of close-up photography. Back in the days when all cameras used film and digital technology had yet to be invented, I tried every method I could dream up to get closer and closer to my intended subject.
My first “real” camera was a Nikkormat FTN, 35mm. I loved being able to see through the lens and adjust my focus and distance manually. I had only one lens for the Nikon, the 55mm normal, and I soon discovered it was not capable of the extreme close-ups I wanted. I even improvised an extension tube from a toilet paper tube.
Get Extreme Close-Ups and Solve the Depth of Field Problem
With my TP extension tube I could get close to my subjects, but I immediately saw a serious problem: my depth of field was only a couple millimeters. I took what could have been a great photo of a cicada, but all I got in focus was one eye and part of a leg. I knew there were lenses available that might solve the DOF problem, but they were far too expensive for my budget. Little did I know at the time that a technological miracle was on the way: the combination of digital photography and “focus stacking”.
The combination of digital photography and focus stacking is one of the greatest technological innovations ever for both amateur and professional photographers. It is a godsend for product photos and online auctions. The more care you take when making the photos for the stack, the better the final output.
Focus stacking and extending the apparent depth of field encourages us to notice minute details in a photo or scene that we had never noticed before. Suddenly we are seeing the world in a whole new perspective. For me, that is the most valuable part of this wonderful technology.