A Comprehensive Guide to Focus Stacking
You’ve heard of it. You’ve made some researches about it. You felt overwhelmed by it. There are legends which narrate some people shiver just by hearing someone pronounce it. Yes, you probably know what I’m talking about: the (in)famous technique called “focus stacking”!
This is considered by many photographers a very complex technique, and while it requires a certain amount of testing before nailing it, it is nothing impossible to learn. Everybody can do focus stacking, it’s all about getting the hang of the process and it will come out easily after a few attempts.
In this article I’ll try to put into words how to do a correct focus stacking and not make any mistakes, starting from the shooting part on the field and ending behind the computer with the post-production phase (I’ll use Adobe Photoshop in this article).
1. What is Focus Stacking and Why You Should do It
As the name suggests, the aim of the focus stacking technique is to merge a certain amount of shots into a final single photo where all the different focus points are stacked together.
In simpler words, it will help you gain a lot more depth of field by taking different shots with individual focus points and then merge them together in post-production.
The logic question that might come into your mind now is: why on Earth should I bother doing all this process, instead of just stopping down the aperture a little bit more? Has Leonardo gone crazy?
The answer is no, I’m still fine; in some particular situations, generally in landscape photography when you have some really close subjects in the foreground or in macro photography when you try to get the whole subject in focus, stepping down the aperture of your lens won’t be enough in order to get the depth of field you need to have everything in focus. You can even try to close down till f/22 or more (if the lens allows), but you still won’t have everything in focus.
Oh, and let’s not even mention the diffraction and loss of quality you would get by shooting with such close apertures.
And that’s exactly why you should do focus stacking: to capture a lot more depth of field than what is possible to catch with a single exposure.
2. When to Focus Stack
I get this question so many times during classes and workshops; once you learn how to play with the focus stacking, you want to use it for every shot you take. Me instead, since it’s a time consuming technique, I prefer to do a focus stack just when it’s strictly necessary.
You will need focus stacking only for those cases in which you can’t have the whole scene in focus with a single shot: wildflowers in the foreground with a wide lens or a close-up of an insect are just a couple of examples.
If you are at a safe distance from the nearest thing that appears in your photo (let’s say 1 meter on a wide lens), there’s no need for any focus stacking, but just by stopping down to f/11 or other normal “landscape apertures” you’ll get everything in focus. Another technique to keep in mind, before switching to focus stacking, is to try the hyperfocal distance of your lens: I won’t explain here what the hyperfocal distance is since it would require a whole article to explain it properly, but you should know that it is another technique worth considering when you have subjects close to your lens.
Just after you checked that both the single shot and the hyperfocal are not working you should start doing a focus stacking.
As you may have seen from the photos, Dolomites are probably the best place to learn the focus stacking technique. Come with us in a summer tour and we’ll teach you how to master it!
3. How do You Take Focus Stacked Photos?
This chapter is what the article is all about: how to properly make a focus stacked image. We’ll start by checking what pieces of gear you could need for a focus stacking and then we’ll see how to work with them in the field. For the sake of the article, we’ll mainly consider just two photography genres, landscapes and macro, which are the ones where focus stacking is more widely used.
3.1 What You'll Need
First of all, what do you need to capture a focus stacking sequence? We’ll talk separately about landscape and macro photography, since these two photography genres require different pieces of gear.
Let’s start with the easier one:
Landscape photography: when doing a focus stacking in landscape photography, all you’ll need is your camera/lens and a tripod, nothing more. The tripod will be fundamental, without it you won’t be able to do a focus stacking. Why? Because all the different shots must be perfectly aligned and identical, there shouldn’t be any difference in terms of framing. When shooting handheld, even if you have the most steady hands of the world, there will be some slight changes between one shot and the others, and the editing software might not be able to align them later.
And then, let’s talk about the trickiest one:
Macro photography: if you are just starting out and want to try the focus stacking technique, you don’t need anything more than your camera equipment and your tripod, same as for landscape photos, since you’ll manually shift the focus during the sequence. If you are interested in a more practical way to do focus stackings, you should know then that there are some tools called “focusing rails” which were created with the goal to help you during your focus stacking sequences.
How do these focusing rails work? There are two types: manual and automated ones. Unsurprisingly, with the first ones you’ll have to move the camera along the rail manually, while with the latter the movement will be made by the rail itself.
If you are curious about these rails, you can invest a few bucks in the manual ones as they generally come way cheaper than the automatic models.
There one more option though to be considered, in case you are not interested in the focusing rails: the Helicon Tube. Helicon is one of the world’s leading focus stacking softwares (we’ll discuss about this later), and the same company released, around one year and a half ago, this extension tube that goes in between your camera and your lens; it doesn’t sound that revolutionary till now, isn’t it? There is nothing new in extension tubes. But follow me closely: by having the ability to connect to your phone and control the tube remotely with a dedicated app, you’ll be able to decide how many shots to make and how much to switch the focus between one shot and the next one. Already sounds more interesting, right? Oh, and then you’ll manage to edit the focus stacking sequence into their software without incurring into any sort of problems. Sounds like a great tool for me now!
3.2 How to Shoot for Focus Stacking
The time to put the tools we talked about in the previous chapter to good use has finally come! Now we’ll see how to capture a focus stacking sequence on the filed without any mistakes; again, we’ll talk separately about landscape and macro photography, since the two genres require different approaches to focus stacking.
3.2.1 Landscape Photography
Let’s start with the easier one again, landscape photography.
Let’s say that you are wandering in the mountains during the summer season, and you find some nice flower-filled meadows; I bet that you saw plenty of shots with some captivating big flowers in the foreground, and you’d love to replicate that kind of style, right?
As an example, I’ll use one shot of mine that I took a couple of years ago at the Seceda, a beautiful location in the Dolomites:
So, as you can see, to produce the final image (which you’ll find in the slider), it took me an 8-shots focus stacked sequence. Let’s go through all the steps I’ve done to make it:
- Find the right composition handheld: when you arrive in the area you plan to shoot, start looking out for possible compositions without the tripod. It will help you try a lot more perspectives in no time.
- Set up the gear: after you found a composition that you like and think it’s working, it’s time to put on the tripod! It can take a few minutes sometimes to set everything up since you’ll probably work at a weird, uncomfortable angle, generally almost at ground level.
Pro tip: if your tripod allows you to remove the central column, go for it: it will give you more flexibility while setting up and you won’t have a minimum height from the ground anymore.
- Find the right exposure: after you setted up the gear, it’s time to take a few test shots and find the exposure that you want. In case you are not able to capture the whole dynamic range of the scene in a single shot, take all the different exposures you need before (or after) starting the focus stacking sequence. In the example up here, I had to recover some of the highlights in the mountain wall and the clouds, so before that sequence I also took a darker shot just for those elements. For these exposures, remember to keep the focus to infinity, to have the mid/background in focus.
- Make the sequence! How? It’s easier than you’d think: once you’ve found the right exposure, start from infinity and take as many shots as you need till the closest thing in your frame is in focus. I generally take even more than I actually need, just to be on the safe side. For the shot above here I didn’t need 8 shots as I could probably get away with 4 or 5, but you never know! It is hard to check what exactly is in focus on the camera screen while you are shooting on the field, so it’s nicer to have a few shots more rather than a few shots less.
Most of the times, I don’t even look at the camera screen anymore: I just rotate a small bit of the focus ring and take a sequence of 7 to 10 shots (depending on the scene), from infinity till the other end of the focus ring, which in my case is 0.28cm (on the Nikon 14-24mm). In this way, by using close apertures like f/10-f/11-f/13, I’ll basically be 98% sure to have everything in focus from the furthest thing till the closest object in the scene: of course, I can’t place anything closer than 0.28cm, otherwise that subject will be blurred as the lens can’t focus that close.
Pro tip: to avoid any issues during the post production phase, be sure not to change any of the settings during the sequence. It might seem obvious, but sometimes it comes natural to correct the shutter speed/aperture/ISOs: even a difference of ⅓ stop will give you some bad headaches in post production, so be sure that all the shots have the same exposures.
Pro tip #2: everything that is subject to focus stacking must be in the exact same position for the whole sequence. If there is something moving in the frame, use exposure times fast enough to get everything still and sharp. Think about this: if in one shot you have a flower in a certain position and in the next one it will have moved to another position (let’s say because of the wind), you won’t be able to merge those frames together anymore.
Wanna practice? (Yep, part 2)
If the Dolomites feels a little bit too adventurous for you, Tuscany in spring might be your next option on the list to practice with focus stackings. Check out our day tour!
3.2.2 Macro Photography
Let’s talk now about the more complicated focus stacking in macro photography; keep always in mind anyway that the general process will be the same, that is to shoot a sequence of images with different focus plans, just a little bit more complex than the one necessary for landscape photography.
The first thing you should consider is that the amount of shots you need to have everything in focus in a macro picture will be a lot more than the amount for a landscape picture: why? Because at a magnification rate of 1:1 (or even more), the depth of field will be incredibly thin, with just a tiny portion of the subject sharp while the rest will be blurred.
Let’s see how to complete a focus stacking sequence in macro photography, step by step:
Find your subject and compose: well, this step works pretty much for all the photography genres and not just for macro photography. In this case though, what I mean is to find a suitable subject for focus stacking: the number one priority is that it must stand still for the whole sequence (as for landscapes), otherwise it won’t be possible to merge the photos later.
Set up the equipment: while in landscape photography during this phase all you needed to do was open up and position your tripod, here things are a little more complicated: you might need to mount a focus rail or Helicon tube, together with an external flash to highlight your subject and maybe a light diffuser to give the scene a more natural look. All I can say is that sometimes the process is quite straightforward as the situation doesn’t require a lot of tools, sometimes it can be as tricky as recreating a “micro studio” on the field, with flashes, rails and what not.
Manually take the sequence: in case you don’t have any rail or tube, perform the serie of shots like for the landscape pictures, just by rotating a small bit of the lens focusing ring. While in landscapes 4 or 5 shots are generally enough to complete the sequence, here you could need as many as 40 shots per serie.
If you have a manual macro rail, without touching any of the settings or the focus, just slightly move the camera along the rail after every shot. Basically, instead of changing the focus of the lens, you’ll change the distance of the camera from the subject.
Let the Helicon tube/automated macro rail do their magic: in both cases, all you have to do is decide how many shots do you need for that specific sequence and how much to move the focus between one shot and the other. That’s it. The tube or the rail will take care of the rest by moving the focus/camera and capturing all the shots you need.
3.2.3 Focus Stacking in-Camera
In the last few years, camera producers added a very interesting features in their newer camera models: the ability to focus stack automatically from the device!
Yes, you heard me: some of the most recent cameras (and in the near future probably all of them) will do all the hard work for you, and as for the automated rail/Helicon Tube, all you’ll need to do is select how many shots the camera has to take and the start/end points of the focus stack.
No need to say that this feature will work only on lenses with autofocus; on elder lenses you won’t be able to automatically do the focus stacking with the camera.
Come on, another one!
Now that you read everything about focus stacking, maybe it’s time to learn also HDR photography! Check out this article and discover all about it.