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  • Daniel Knop

Focus Stacking Setup

Aktualisiert: 25. Apr.

While many macro shots are taken freehand or with a tripod, focus stacking work with film scanner or microscope lenses requires a special setup. A technically proven setup variant is presented here, together with its predecessors.

A focus stacking setup with camera, bellows and light diffuser, illuminated with two studio LED spotlights, two computer monitors behind it
Not only the insects we photograph have undergone an evolutionary development, but also technical devices such as a focus stacking setup – a kind of technical evolution

What do model railroaders and focus stacking enthusiasts have in common? Nothing at all, you might think. But far from it, there's more than you might believe. Our enthusiasm for nature, especially bugs and other insects, or for flowers and their aesthetics, is similar to a model railroader's enthusiasm for the aesthetics of the miniature landscape that he lovingly designs and builds. His rail network, highly complex and well thought out, is comparable to our focus stacking setup – technology in its purest form, characterized by ingenuity and experience. And the locomotives on his model railroad, his pride and joy, ultimately match our lenses in this comparison.

This article will focus on the second of the analogies mentioned above, the focus stacking setup, i.e. the technical setup that supports the camera and the subject and moves them towards each other step by step.

The first setup – 2006

The vast majority of focus stacking enthusiasts enjoy designing their own technical setup and constantly optimizing it. I am no different myself. I started out 18 years ago with a very simple construction, manually operated and equipped with the simplest of tools. As I previously had a Rolleiflex medium-format camera with a macro lens and bellows, my approach to my new passion was different to what is usual in this hobby: instead of the long tube that is usually used or the extension rings that are screwed together to create the right distance between the camera sensor and the lens or tube lens, I used a bellows because I was very familiar with it.

I chosed a black granite plate as the base for the setup. It was heavy and promised to be unshakeable. On top I glued an aluminum plate with a tiny dollhouse-sized linear table that supported the camera – done.

A very simple focus stacking setup, with a camera, bellows and microscope objective, underneath a tiny linear stage, in focus a body part of a dead wasp
The first setup for focus stacking – here it was about the sting of a wasp

A ping-pong ball, ground on both sides, is placed on a microscope objective as a light diffuser; the rear body of a dead wasp can be seen in front of it
It also works with the simplest means – somehow …

The sting of a dead wasp in close-up
The surprising thing about this sting was the barbs, because wasps don't normally have them

The first objectives came from my Leitz Orthoplan microscope (and were actually unsuitable because they would have needed a Periplan eyepiece). My first diffuser followed the general recommendations of grinding a table tennis ball on both sides and sliding it onto the objective – completely unsuitable for good photos. So the equipment was very modest, but because my requirements were equally modest at the time, it worked very well and I was very satisfied. Experts criticized the color fringing on my pictures due to chromatic aberrations (because the correction by the Periplan eyepiece was missing), but I didn't think that was so bad. At the beginning.

The second setup – 2010

For the second setup, I replaced the old bellows with a modern one from Novoflex and also constructed a height-adjustable lens holder from the metal parts of an old bellows system from the 1960s. A motorized linear stage, the Stackshot model from Cognisys from the USA, was placed under the camera. All this made it more practical, but didn't change the image quality dramatically at first. Gradually, the desire to improve the aesthetics of my photos grew in me, step by step. And as I was lucky enough to be in close contact with the absolute luminaries Charles Krebs, Rik Littlefield or Robert OToole, who unfortunately died unexpectedly and far too young a few days ago, as well as many others on the internet forum Because of their enormous willingness to help, I was able to learn very quickly.

Focus stacking setup with camera and bellows, including a stackshot linear stage from Cognisys
The second setup was motorized and had a modern bellows and a height-adjustable lens holder

The third setup – 2012

The third Focus stacking setup was already in a different league and was not only carefully planned, but also based on experience, so it was not just a jump in at the deep end. The base was a transparent acrylic glass plate with polished edges and an L-shaped front plate glued on. I chose acrylic glass because I was very familiar with working with this material. My basic idea for the design was to also be able to operate the whole thing vertically, but in the end I never did because I had my Orthoplan microscope next to it.

Two CNC rails made of steel were mounted on the base plate, on which four ball-bearing carriages were mounted, which could be moved forwards and backwards as a rough adjustment of the camera position. On these carriages I mounted a massive, heavy linear stage from industrial supplies, with fine adjustment, a discarded tool with a lot of patina and probably a long workshop history in some factory hall. On top of it I placed the stackshot unit, the motorized linear stage on which the camera sat. In this way, I could roughly position the camera by sliding it, use the linear stage for fine positioning and also chose between a manual stack and a motorized stack, all without any modifications.

For the object holder, the metal skeleton of the 1960s bellows device was screwed to the front plate as a height-adjustable base.

A focus stacking setup with a base plate made of transparent acrylic, on which two CNC rails support a manual linear stage on which a motorized stackshot linear stage sits, carrying a camera with bellows device
The third setup had a base made of acrylic glass and a pair of CNC rails as well as an additional manual linear stage. In addition to microscope lenses, macro lenses were also used here.

I enjoyed using this third setup for many years, and when Robert OToole gave me crucial recommendations for a better diffuser, my image quality took a huge leap forward.

In 2018, however, this CNC rail was too short for me because I also wanted to work with my Leica Apo-Elmarit 100 f/2.8 macro lens, which had a very long focusing distance. So I replaced the rails with longer ones and added an additional acrylic plate as a base. Otherwise the setup remained unchanged, apart from the fact that I replaced the stackshot linear stage with the newly introduced Castel micro from Novoflex. And participants in my focus stacking workshops, which I held to familiarize beginners with the subject, got to know this setup and recreated it at home.

A long focus stacking setup seen from the side, with CNC rails on an acrylic plate, on top of which is a manual linear stage supporting a motorized Castel micro linear stage from Novoflex. The camera sitting on it has a Balpro 1 bellows unit, also from Novoflex
In order to be able to use macro lenses with a large shooting distance, the base plate was extended and the CNC rails replaced with longer ones

Detailed image of the camera trolley on a focus stacking setup, below a manual linear stage sliding on CNC rails, above it a transverse macro slide, on top of it a motorized linear stage Castel micro from Novoflex, which carries the camera with bellows
1 base plate, 2 CNC rail, 3 carriage, 4 manual linear stage, 5 cross-mounted macro slide, 6 motorized linear stage, 7 bellows unit

The fourth setup – 2021

But nothing is so good that it can't be improved, and so I came up with my fourth version, which I still use today, albeit again with a few detail optimizations that have emerged over the last few years. This time, the basis is not an acrylic plate, but three aluminum profiles positioned crosswise. A CNC rail profile is mounted on this, but not with two separate individual rails, as in the third version, but a one-piece double rail. This means that there is no difference in distance between the two rails, which allows the carriages to move much more smoothly and evenly.

To achieve more stability, I have a small side rail at the rear, on which goosenecks can also run on their own small trolleys, e.g. to carry flash units or a UV lamp for fluorescence photography.

View of a focus stacking setup consisting of a CNC double rail on which there is a sliding carriage for the camera, one for the lens holder and one for the gooseneck flash holder
Technical basis of the setup: a camera trolley on the left, a lens holder trolley in the middle and a trolley carrying goosenecks for flash units on the right

View of a focus stacking setup, on whose CNC double rail four sliding carriages carry the functional units: camera with motorized linear stage and bellows on the left, light diffuser in the middle and lens holder next to it as well as holder for two gooseneck flash holders
Fully equipped, the light diffuser can also be seen

Maximum flexibility

The next point that was important to me was that all the elements on the large rail should be movable. This gives me maximum flexibility. For work on the camera like changing lenses and other things, the diffuser trolley and object holder trolley are pushed all the way to the right. For differentiated work on the object holder, on the other hand, I push the camera trolley and diffuser trolley all the way to the left. So there is always enough space. I also have a detachable object holder so that I can place it on another work surface such as the desk for very difficult object preparations and rotate it there as required.

Construction drawing of a focus stacking setup with CNC double rail and several sliding carriages to support functional units
Planning drawing of the focus stacking setup – one of the basic ideas was to be able to use the trolley with the flash unit holders both from the front and from behind

Initially, I worked with three or four small Godox flash units (TT350C, also recommended by Robert OToole), which sat on long goosenecks and could be placed around the diffuser as required. This worked wonderfully, apart from the fact that you had to worry that one of the batteries would give up in the middle of every series of shots. The solution to this is now called a studio flash with mains connection: two of these devices are suspended from a ceiling bracket and can be adjusted in height. If required, they can be replaced with two studio LED spotlights from the same manufacturer; the mains connection cables remain unchanged.

There is also a manual linear stage at the bottom of the camera trolley in this setup, which can be used to shoot by hand – at least in theory. However, I only use it for fine adjustment of the camera position, but it is absolutely irreplaceable here.

On top of it is the Castel micro from Novoflex. Above it is the bellows unit, without which I could no longer imagine all the focus stacking work, if only because of the practical plates at the front and back, which can be easily loosened with two screws, for example to change the lens. Lenses of different types each have their own plates, which makes it possible to change them on the fly.

View of a focus stacking setup with full equipment in action, a hornet Vespa crabro is photographed and can be seen on two computer monitors
Instead of the flash units, the setup is now equipped with two ceiling brackets to which either two studio LED spotlights or two studio flash units can be attached. This provides a mains power supply during the shoot.

Three lenses of different sizes standing next to each other, each with its own large, round mounting plate, with a Novoflex Balpro 1 bellows behind it
On both the camera and lens side, the connection to the bellows is made via round plates, so that all different lens designs have been equipped with corresponding connection plates and can be changed easily.

Everything in view

Next to the setup is not only the Castel-micro control unit, but also a 27-inch monitor, which is connected directly to the camera via HDMI and shows the Live View image. This allows me to see the exact positioning of the object or the camera carriage and the placement of the focus zone and also to move it precisely using the fine adjustment screw on the lower linear stage. (In the present case with control unit on the left and object positioning on the right, the Live View image is required on both sides, especially as there is a microscope further to the left which is also motor-controlled. This is why there are monitors on both sides that show the same image. Normally, however, one is fully sufficient).

However, a very inexpensive, often older 2K monitor is sufficient for this; the Live View image provided by the camera is only calculated for the internal mini display, and this image signal is not even sufficient for the display of a 2K monitor. And also make sure you use a camera that has two separate connections for the monitor and remote trigger, as some cameras only have one USB socket to which you can connect either the monitor or the remote trigger (or focus stacking control unit). This means that you would not have a motorized control with large Live View image.

View into the interior of a large light diffuser, which is illuminated by two studio LED spotlights; inside is a dead, taxidermied hornet Vespa crabro, which is being photographed and can be seen on two computer monitors behind it
The object holder is on its own trolley, but if the distance to the lens exceeds the shooting distance, a second placement option is available directly on the diffuser trolley

Movable in two axes

On the trolley on the right, which carries the object holder, there is a second small rail mounted at right angles to the main rail. The reason for this is my desire to occasionally move the object forward to a more comfortable working position, e.g. to carry out tiny detail manipulations. This rail is not absolutely necessary, but sometimes very helpful, especially as it allows you to move the subject very precisely to the left or right in the monitor image before starting the series of shots. However, the camera carriage also has a transverse macro rail that can be used to move the camera left ad right, e.g. to center the object on the monitor at the start of a series of shots. This would not be necessary in this case.

A second object holder standpoint is located on the diffuser carriage, virtually in a cut-out in the diffuser itself, because some lenses have a very short working distance, and the normal distance between their front lens and the object holder carriage would be too great. Examples of this are some scanner lenses, such as the Minolta Dimage Scan Elite 5400 or the Scanner Nikkor 40 from Nikon. In such cases, the object holder is placed directly on the diffuser carriage, and this position can also be moved transversely to the optical axis.

Complete system for focus stacking images, on the right the setup with camera and two live view monitors, on the left two computer monitors standing on a desk under which the broholmer Bailey is lying, all monitors show colored wing scales of the butterfly Chrysiridia rhipheus in high magnification
The focus stacking workstation is complemented by the two computer monitors, which show the progress of the shooting series (left) and the freshly imported single image (center). While the Live View image before the shot can be seen on the right of the setup, the two high-resolution monitors on the left show the respective image after the shot, with authentic reproduction of exposure, color reproduction and position of the focal plane. And, before you ask: The name of the cuddly Broholmer doggy is Bailey

What wishes remain unfulfilled with this setup? None at the moment, actually. In addition to the Orthoplan microscope, I use an old but very stable microscope stand from the 1960s for vertical work, e.g. when photographing snowflakes, which will be presented in a separate article. So at the moment there is no need for optimization. However, it is of course always possible to come across new motives that also require new ideas in terms of shooting technique. And then the cards may be reshuffled again: the only constant is change – just like in real life.

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