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  • Daniel Knop

DIY macro flash diffuser!

Macro shots of pollinators and other insects or of blooming flowers in the garden are actually not particularly difficult. However, I wanted to make the light distribution as homogeneous as possible and also optimize the color effect of flowers and insects. To achieve this, I modified my IKEA light diffuser, which I use on my focus stacking setup, for mobile use with a macro lens – for normal macro shots or in-camera focus stacking (focus bracketing). The result is a compact device with two flash units, which I would like to present here – for anyone to replicate.


A man uses a double flash holder to photograph pollinator insects on flowers growing in a large, fossilized giant clam. On the left of the picture you can see a camera with a lens and a double flash holder, inserted into the picture as a cut-out.
Home-made double flash holder with large light diffuser in macro use on the office terrace

My core idea, which was at the very beginning of this construction, was to turn a conventional tripod clamp by 180 degrees so that the mounting device was not at the bottom, but at the top. This provided an ideal mounting option for a holder that could carry two flash units. Even this constellation without a diffuser spontaneously produced fascinating shots, because it created a pitch-black background with the aperture wide open, so that the colorful subject was virtually cropped, even when photographed in bright sunlight.


But that wasn't my goal, and so the next stage of expansion came. The diffuser that I use on my stationary focus stacking setup is based on the shade of a ceiling light from IKEA, model "Melodi", diameter 28 cm. With a specially made fitting, into which I cut the curvature of the diffuser, the assembly was quite simple and the image result was inspiring.


Macro shots of individual flowers, with tiny predatory spiders waiting for hoverflies, or of hoverflies carefully inspecting each flower and searching for predatory spiders, were suddenly a firework of color. No overexposure in individual areas, the colors of zinnia, cosmea & co. and all the pollinators were suddenly overwhelmingly strong, even without any post-processing. And such photo opportunities have addictive potential. I soon knew every crab spider in the flowers by first name, especially because I have a medium-sized sea of flowers right next to the house.


A pollinator insect sits on a purple flower and inserts its long proboscis
A large woolly hoverfly (Bombylius major) sips nectar with its long proboscis

A pollinator insect sits on a purple flower and dives deep to suck nectar while stretching its hind body into the air
Maybe this isn't the prettiest butt in the world, but the bar is set pretty high ...

A pollinating hoverfly with an unusual body shape sits on a purple flower
The Common Snout-hoverfly (Rhingia campestris) belongs to the hoverflies, but develops an extremely bizarre shape

A wild bee sucks nectar from a purple cosmea flower
Wild bees are among the most photogenic flower visitors

A small, light green crab spider sits on the edge of a red cosmea flower
This small crab spider sits in a red cosmea flower waiting for pollinators, e.g. hoverflies

A white crab spider with a brown body pattern sits on the underside of a pink Cosmea petal
While lurking for prey, the small crab spider likes to stay on the underside of its flowers to avoid becoming a victim of a wasp or hornet. Cosmea flowers are fantastic for such observations!


The double flash holder


A double flash holder with two flash units and a large, white, bell-shaped light diffuser is attached to a Canon R3 digital camera and a 100 mm macro lens
The home-made flash diffuser with fixed diffusion umbrella and two tiltable flash units

A double flash holder with two flash units and a large, white, bell-shaped light diffuser is attached to a Canon R3 digital camera and a 100 mm macro lens
Looking from the side, you can see the distance between the flash units and the diffuser surface, which should not be too small

A double flash holder with two flash units and a large, white light diffuser can be seen from above
The distance between the flash unit and diffuser can also be seen from above

A double flash holder with two flash units and a large, white light diffuser can be seen from the position in which the attached camera would normally be located
The inverted tripod clamp supports the entire construction and attaches it to the lens

A double flash holder with two flash units and a large, white light diffuser stands vertically and can be seen from its underside
The cut-out on the underside of the flash diffuser should be large enough to be able to slide it completely over a plant to be photographed

The manufacture

Of course, you can also buy ready-made devices for such macro photos with or without focus stacking. However, these usually work with a single flash unit, and I wanted to use two. My intention was not to save a few euros, but to design something myself that came as close as possible to my goal of light distribution and intense color effects.


Preparing the IKEA lamp shade is quite simple. It is completely gutted and freed from the inner part with the lamp socket (be careful not to injure yourself, the material is very tough and stubborn). A large cut-out should then be made on the underside so that it is easier to get close to a plant, for example.


The individual parts that make up the flash diffuser are clearly arranged next to each other
All the individual parts of the flash diffuser

The most important thing to start with is a tripod clamp that fits the lens in question. You should therefore choose a lens from the outset to which a tripod clamp can also be attached, as many lenses have a correspondingly wide strip of the housing on which there are no transverse structures and, of course, no switching elements. The diameter of the clamp must also match the lens. Another tip: If possible, choose a tripod clamp with a joint that allows you to open it up to place it around the lens. The one shown in the pictures does not have this and is very awkward to attach.


The heart of my mount consists of two plates. The first plate is in the center and is attached directly to the tripod clamp with a screw. The second sits across it and is angled like a roof on both sides; it carries the two flash units. Both plates must be made to fit your lens and flash units, in length and, in the case of the second plate, also in the angle. It is best to start by experimenting with dummy plates made of sturdy cardboard, which you can then use as templates for the plastic.


The left of two pictures shows a bell-shaped flash diffuser made of plastic, which is screwed to a narrow plate made of PVC. The right-hand picture shows a PVC mounting plate to which two flash units are attached.
Left: The diffuser screen is screwed to one of the mounting plates with a suitably ground intermediate piece. This spacer can easily be made from plastic or wood. Right: The two flash units are screwed onto the double-angled mounting plate.

I chose 5 mm thick PVC as the material for these two plates, which is even easier and more pleasant to work with than acrylic glass ("Plexiglas"), but that also works well. Just make some cardboard prototypes to get a feeling for the right length of the strips and the necessary angulation, because your flash units should be placed at some distance from the diffuser, at least about 50 mm, otherwise the light diffusion could be poor.


Nylon screws are particularly suitable for mounting, because anything that saves weight is welcome with a flash diffuser like this.


The left of two pictures shows a tripod clamp and three mounting screws, the right shows a fully assembled flash diffuser with a PVC mounting plate to which two flash units are attached.
Left: The tripod clamp is used to attach the holder to the macro lens. Right: The finished construction is light and easy to handle.

I use two small Canon flashes, but in the meantime I could just as well imagine using this holder with the small Godox TT350 flashes, which I use for stationary focus stacking, or of course with flash units from other manufacturers. The Godox TT350s are very inexpensive, extremely reliable and also available for several camera systems (Canon, Nikon and Sony). However, they are slightly higher than the Canon units shown here, so that the transverse mounting plate would have to be angled and positioned accordingly so that the distance between the flashes and the diffuser is optimal.


Which lens?

In principle, any macro lens that allows a tripod clamp to be attached is suitable. I myself would only use an autofocus lens here, but that is a question of personal preference. My favorite is the relatively new Canon macro RF 100 2.8 from the L series, but I also occasionally use this device with the Canon MPE 65 5:1 lens, but then I don't have autofocus, so I use the shooting distance to focus. But the depth of field becomes so shallow from about 2.5:1 that it is difficult to get the whole subject into the focus. But this is also a question of personal preference, as blurring can also be used as a creative tool.


A wild bee sucks nectar in the center of a cosmea flower
Good light diffusion and strong color effect: wild bee in the middle of a cosmea flower

A wild bee sucks nectar in the center of a yellow flower
The large, bell-shaped diffuser does not seem to disturb the wild bees sucking nectar

Radio control or cable?

Cable or radio, that also depends on your personal preference. I prefer to work with cables because such a system works more reliably and you don't need to worry about a battery-operated device that could fail. Others prefer to use a radio transmitter, e.g. with the small Godox flashes, for which a suitable transmitter is available. However, this flash diffuser is not suitable for the infrared flash triggers often used in the past, as they require a ceiling via which the light signal from the trigger is thrown to the flash units.


The twin flash connection cable with flash mounting shoes can be easily obtained from Internet providers, but the plug connections are camera or manufacturer-specific.


A wild bee sucks nectar from the center of a yellow flower
This type of light distribution is almost impossible to achieve with flash photography without a diffuser

A small white crab spider sits on the petals of a pink cosmea flower
Small crab spiders are regularly found in flowers, often in pairs

Why two flash units?

Of course, you can also work with a single flash unit that sits in the center on top of the camera and whose light is directed onto the subject via reflective diffusers. There are always several roads that lead to Rome. But I have the impression that I can distribute the light on the subject better with two flash units that shine on both sides of the semicircular diffuser. In addition, with two flash units, each of which only has to emit half the power, I have the chance of freezing movements even better by shortening the burn-off time accordingly. After all, pollinators on flowers are often moving objects. Bear in mind that a flash unit never varies the brightness, but only varies the amount of light over different burn-off times, and the longer this light pulse is, the more motion blur will appear in the picture, e.g. when an insect is flapping its wings quickly. Two flash units therefore freeze movements better than a single one.


Internal focus stacking with double flash holder

Many modern mirrorless digital cameras now also offer the option of internal focus stacking in order to compensate for a very shallow depth of field in macro shots and to combine the focus zones of several images into a new single image. This is often referred to as "focus bracketing" in the software, but it is basically the same thing. For such shots, e.g. in the garden or on a flower meadow, the flash diffuser presented here is simply ideal, because you not only have a good, diffuse light source with excellent dispersion, but everything in a single unit. The flash units are exactly in the required position and you can concentrate fully on the subject while you may be lying prone in the flower meadow.


With in-camera focus stacking, you select an approximate distance length (e.g. a length value between 1 and 10) and the number of individual shots (e.g. 2 to 100) in your camera's control software. The camera then takes these individual photos using the lens autofocus, and all you have to do after the shutter release is hold still. Some cameras process the shots immediately internally to output the final image. Others, however, export the individual shots for subsequent processing, either in special software solutions such as Helicon Focus or Zerene Stacker, or in image editing software like Affinity Photo.



Menu of the camera control software with input of various parameters
For internal focus stacking, only a few settings are required in the camera's control software, here 1. activate focus bracketing, 2. enter the number of desired images and 3. select the length of the desired total distance (first to last image)

A golden rose chafer sits on a purple flower and sticks its mouth parts deep inside to suck nectar
Insects such as this golden rose chafer (Cetonia aurata) can be captured in focus throughout using internal focus stacking, as can flower blossoms, whereas these are usually not completely covered by the depth of field in normal macro shots

With internal focus stacking, you only need a few individual photos for a short series of images, such as a pollinating bumblebee. While microscope lenses in stationary focus stacking often require several hundred shots, here you have an aperture that extends your depth of field. In addition, a macro lens already has a considerably greater depth of field than any microscope lens. Another advantage is the fast sequence of such a series of images, as this usually takes place within a second or just a little more, so that you do not run the risk of blurring the image due to strong movements.

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3 Comments


Guest
May 09

Could you make some comments about the tools and techniques you use to cut/shape the "Melodie" lamp shade? I have tried a Dremel Tool with little success.

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Guest
May 13
Replying to

Thank you for your reply. I am making good progress on my Ikea diffuser. Will send you a photo when done!

Martin Drexhage

Sturbridge, Massachusetts USA

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