Figure 4. Camera sled construction. Left: Moving sled on wheels inside outer frame (camera removed for clarity). Right: Gantry wheels securely pinch grooves of 2040 extrusion rails.
I decided to use a sled design where
the camera is securely attached to a wide frame that moves forward and backwards on a multi-wheel gantry. Te outer frame provides a strong and stable support for the two rails that engage the gantry wheels shown in Figure 4. Te wheels fit snugly into the groves of a 2040 aluminum extrusion. Te sled has only one degree of freedom. It can move forward and backwards but not sideways, not up and down, nor can it rotate in any direction. Tis kind of stability is essential for super sharp photos.
Moving the Camera Sled To get acceptable photographic
results, our images have to be compatible with focus stacking software. Tat means each image should have some in-focus overlap with the previous and subsequent image. It also means that each step between images should be small and repeatable. Macro photographers solved this
problem long ago with the Macro Rail (Figure 5). Te camera is attached to a camera mounting point moved by a long lead screw. Rotation of a wheel spins the lead screw which advances the mount and camera fractionally forward. But the size and weight of the
Extreme Macro Camera-lens assembly makes direct mounting onto a macro rail undesirable. Te camera-support-
Summer 2026 FUNGI Volume 19:2 37
rail combination is top-heavy and prone to vibration when connected directly onto the macro rail. Tat is why I use a wide camera sled driven by the macro rail instead. Te maximum step size between
photos varies with magnification. With my 20x lens a step size of 30 μm seems to work well. Tere are automated macro rails that can be programmed to advance the step size you want, trigger a camera shutter release, then advance another step as many times as you like. Unfortunately, my camera, a Sony
A7C, does not have an easy way to interface with these devices. And there
is a certain satisfaction in triggering each step and watching the image change with each shutter release. Real purists tend to manually
advance the camera between photos. I compromise. My manual macro rail is linked to a stepper motor (Figure 5, page 38). Te motor takes 200 steps for one revolution. Te timing belt converts one revolution of the stepper motor to 1/4 of a turn of the macro rail screw. Te result is one step of the stepper motor moves the camera sled ahead by 1.5 μm or 0.0015 mm. Tis is too small a step for my work. Te stepper motor controller (Figure
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