Macro still life photography of insect compound eyes and water droplet refraction: flash soft light diffusion and nano-scale two-way focusing rail practice

1. The physical wonderland and extreme optical challenges of the microscopic world

When the magnification exceeds 1:1 and enters the microscopic realm of 2:1 or even 5:1 (such as using Laowa 25mm f/2.8 2.5-5X or Canon MP-E 65mm):

1. Physical desperate situation with micron-level depth of field:

• At 3:1 magnification, even at f/8, the effective depth of field is less than 0.1 mm (100 microns)**!
• A single eye of a fly is far beyond the depth of field range. Only a few single eyes in the front and back are clear, and the rest are all blurred;

2. Light attenuation black hole (Bellows Factor):

• The lens is extremely extended forward, and the actual effective aperture plummets to f/22 to f/32. The viewfinder is pitch black, and high-intensity external artificial light sources must be relied upon to fill the light.

2. Practical operation of depth of field slicing with nanoscale focusing rail (Macro Focusing Rail)

At the micron scale, rotating the focus ring of the lens will cause drastic changes in magnification. It is absolutely prohibited to focus by rotating the focus ring!

1. Fix the lens focal length and move the entire camera system:

• Fix the camera and lens securely on a high-precision two-way macro guide (such as a Cognisys StackShot electronic guide or a manual micrometer guide);

2. Micrometer Step-by-Step Slicing:

• Set the step accuracy to 20 micron to 50 micron (0.02mm - 0.05mm);
• Each time you advance forward, the shutter release fires one shot;
• Take 50 to 150 cross-sectional photos through continuous sectioning to completely scan the compound eye structure of the insect's entire head;
• Send it to Zerene Stacker or Helicon Focus for deep synthesis in the later stage, showing the breathtaking details of each small hexagonal lattice and fluff of the compound eye.

3. The soul of macro lighting: super large enveloping curved double-layer diffuser (Diffuser Cone)

Insect exoskeletons and water droplets have extremely high specular reflectivity, and direct flash will leave dazzling white spots:

1. Why does the standard softbox fail in the face of macro?

• The lens is often only 2 to 5 cm away from the insect being photographed (extremely short working distance);
• Ordinary softboxes are too large to fit into the narrow gap between the lens and the insect;

2. Professional macro "Donut/Ice Cream Cone Diffuser" production:

• Use a flexible white translucent polypropylene plastic sheet (PP sheet/sulfuric acid paper), roll it into a cone-shaped cover and put it on the front part of the lens;
• Aim the flash head at the outside or top inner wall of the cone;
• Miracle of physical light diffusion: Light undergoes thousands of omnidirectional diffuse reflections in the semicircular inner wall, tightly wrapping the insect 360 degrees from all sides;
• The insect carapace photographed has a silky warm luster, and the inside of the water droplets reflects a perfect circular sky, without any high-light overexposure.

4. Microscopic composition skills of water droplet refraction (Droplet Refraction)

1. Surface Tension Conformal Secrets:

• If water drips directly on plant stems or thin threads, the water droplets will easily collapse and slide;
• Drop a small amount of pure glycerin (Glycerin) into clean water. The high viscosity and extremely strong surface tension of glycerin can allow the water droplets to form perfectly plump spherical water droplets, which will not evaporate or collapse in the breeze for several hours;

2. Refraction of the "inverted real image" of the background flowers:

• Place a bright flower approximately 3 to 5 cm directly behind the water drop;
• Full microscopic spherical water droplets are equivalent to a natural biconvex lens with extremely large optical power;
• Accurately lock the camera focus on the refracted reflection on the surface of the water droplet**;
• The inside of the water droplet instantly reflects a miniature, crystal clear, inverted and blooming microscopic flower, presenting an amazing "one flower, one world" surreal microscopic artistic conception.

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