Home Methods Focus Stacking

Focus Stacking

by Güray Dere

I may have repeated it over and over again on other articles, but I’ll talk about it again. As you know, one of the big problems of macro photography is that the clearly visible area is very narrow. Even though we can increase our sharp area by slightly closing the diaphragm, this is quite limited. After a certain value, the quality of the photo is seriously damaged. Diffraction creates a watercolor effect in our photos. We get less and less detail.

In this article I will introduce a method that will be the solution to this big problem of macro photographers.

Focus stacking

No ultra sharp macro photos without focus stacking!

“Focus stacking” is a photo processing technique. A gift from the digital world to us. When we  were in film photography times, we had to settle for what a single photo gives us. After switching to digital photography, the theory of the processing and then the software part had to mature. Now we have it all. With this technique, we are able to process photos and make a work that will eliminate the narrow depth of field problem. But I’m not going to tell you how it is done in this article. We’re just going to look at what it is and what it looks like. You can find a large number of tutorials on “focus stacking” available online.

Focus Stacking technique in studio photography

A mini studio for focus stacking

Focus stacking is often used for studio shooting. Don’t think about photo studios you know. I use the word studio as a controlled environment. A small corner reserved for this job at home is well enough. We position our camera and lighting gear. The subject, the beetle, is standing against it. Background etc. everything is already set. These is our mini studio. Since everything is still in place and our insect is usually dead, we can easily try high magnifications.

Let’s go back to our problem. Especially in high-magnification, our depth of field is so narrow that we cannot understand what we take when we look at a single photograph. The photo below was taken with the studio system, appearing above.

Narrow depth of field with Lomo 8X 0.20 microscope lens

I share a photo  with the Lomo 8X microscope lens to highlight how serious the situation is. I can’t say anything to those who say, “That’s ok.”, so you can use it this way too 🙂

We are entering a laborious process to clearly view the entire object here. . We take the first picture. Then we move the part (focused area) we see clearly a little further and take another picture. Then we move forward to another section and continue shooting. Depending on the lens type, the magnification factor and the size of the subject, this process goes up to hundreds of pictures. At the end of a series of shots like this, there must be a clear part from every region covering the whole object.

Photo series taken for focus stacking process

Then we switch to the second troublesome work. Our goal is to combine them and get a single sharp picture. Photoshop, Zerene Stacker or Helicon Focus software is used for this purpose. The photos are sequential, front-to-back or back-to-forward. Doing this is not always necessary, but gives a more successful result. The program automatically detects focused areas, processes the frames and produces a (not so perfect) result. Pixel color transitions and contrast differences are more obvious in focused areas. So programs can understand it, select only focused pixels, then only take that area from the frame and combines all.

Then we take the mouse and process the problem areas. If necessary, we take a look at all the photo frames individually and carry the details to the places with the problem. After working for a while we reach our award:

Combination of 126 photos taken with Lomo 8X 0.20

126 shots were taken to get this jumping spider photo. RAW-JPEG conversion, rough operation and make-up took a couple of hours. It takes too long and sometimes it’s boring. You can say “Is it worth it?” The answer is “I enjoy it and more importantly there’s no other way to get this photo”.

Focus stacking handheld shots

We don’t always need an established studio for focus stacking. Sometimes I prefer shooting handheld outdoors. Thus, it is possible to photograph many species in a short time. Well, then what do I do?

Usually 1X-4X magnifications are used in Handheld. The problem in these magnifications is not as much as the microscopic studies, but there is a depth of field problem at every level of macro photography. In practice, I try to take 15-20 pictures in the fastest way before the insect moves. In doing so, I try to create a focused area that moves forward or backward. Then, when I look at the results, I often see that I can’t focus exactly where I want to. I have frames aside from the subject or constantly focused on the same place. There can be some areas that are not clearly visible in any photo. I need to keep the number of shots generous to reduce these possibilities. I’m delete useless frames after shooting. About half of the pictures taken go to the trash. 

Handheld focus stacking sequence

If you review this series of photos carefully, the framing is more or less different. In some shots, the spider’s legs remained outside the frame, and in others the sharpness was repeated in the same region. In such cases, Photoshop produces more successful results than the other two programs. When we look at the focus stacked picture, we have achieved sufficient clarity. The spider’s abdomen is purposely out of focus. If we were interested in that part, we would have to take an additional 10 photos.

Focus stacked handheld photo.

Focus stacking in the field

Hand-held shooting is already done in the field. So if you say what is this title, the actual beauty in the field is the use of natural light. For this, we need to carry a simplified versiyon (or all) of our home studio equipment. In spite of all the difficulties of wind, light and live insects, the best jobs in the macro are done in the field. Because I have a separate article, I’ll give some links without further explanation:

(Turkish articles will be translated soon)

Focus stacking challenges

First of all, it is necessary to spend considerable effort on both the shooting and the processing of the pictures. The biggest challenge lies in creating this time. But this is something about ourselves, as a person who enjoy this work, I take back what I said. It’s not a hassle. Let’s talk about the difficulties,

Out of focus region in stack sequence

We did it. We took hundreds of shots. We’ve been working on the computer. Suddenly we realize that final image has blurry areas in the form of a strip. This is a very annoying situation called focus banding that happens if we can’t adjust the step size small enough. Sometimes i can’t wait as I want to see the result immediately. Then I find it painful that my stepping distance is too big and the work need to be done all over again.

Coarse rails or bellows rails are sometimes not enough for precision. No matter how hard we try, there are blurry regions. I will review the Newport Linear Stage, one of the ideal tools for stepping, in the next article.

Photographing live insects and movement

Live aphid stack sequence

We’re not always going to use dead bugs in  high magnification studio shoots. We can apply this method on living things. You just need more patience. You often have to do it from the beginning, so you need to afford it. If the beetle has done something like a serious move, a change of position, we have to throw the whole sequence into the trash. The same goes for the framing. If we hit the camera or the leaf or branch with the insect before it is finished, the operation will be canceled.

But it is possible to compensate up to a level. The animation you see is 35 focus stack frames of a live aphid at 12X magnification. Sharpness progresses from front to back in every frame. You can see that the aphid is very active during the shooting. Nevertheless, as a result of stacking these frames, a single, sharp image can be obtained.

Hareketli ağaç bitinin birleştirilmiş sonucu

Variable light conditions

Focus stacking is a time-consuming process that takes minutes, so it is not possible to get the same light in every frame. Especially when using natural light, it is constantly changing due to natural conditions. Cloud pass, angle of the sun, swinging trees etc. everything affects the amount and color of light. The software we use is powerful but not completely effective. Variable conditions often affect our final photograph in the form of color halos. That means extra work.

As a precaution we are trying to finish our job fast. In particular, we need to speed up the work even if we compromise on quality in situations such as variable weather, moving bugs and wind risk.

  • If the accessories is of high quality, this provides the greatest assistance: A good tripod, head and rail, sturdy holders, external shutter, a camera body with EFSC support… These are nice things 🙂
  • We can increase the focus step size by slightly closing the aperture, reducing the total time by taking fewer photos.
  • We can save time by slightly increasing the ISO and shortening the exposure time.

Battery depletion

We’d better check the batteries of our camera and flash before we start shooting. Battery deplation in the middle of the work can be very annoying. Even if we have a spare battery, changing it will shake the machine and we will not get the same frame and we will go back to the beginning.

Full memory card

In the same way, inserting a new memory card in the middle of the operation or deleting the old pictures from it will ruin the frame and lead us back to the beginning. Even if it isn’t, it will be a waste of time and boredom. Ensure there is enough free memory before you start.

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