Macro Photography Water Drop Refraction Flower Micro Sculpture: Water Drop Surface Tension, Glycerin Mixing Ratio and Double Lighting

1. The geometric optical principle of water droplet refraction imaging: a perfect micro-convex lens

Why can the flowers behind be seen in the water drops hanging on the tips of leaves?

• Convex Lens Real Image Refraction Physics:
• Relying on the high surface tension of water, water droplets suspended on thin stems form a highly bulged hemispherical or spherical droplet under the balance of gravity and molecular gravity;
• The outer arc surface of a water droplet is equivalent to a thick convex lens with a very short focal length (usually only a few millimeters) in physical optics!
• Inverted Real Image:
• When the flowers in the background are placed several times beyond the focal length in front of the water drop (usually 5cm ~ 15cm away from the water drop);
• According to the geometric Gaussian optical imaging formula: [ \frac{1}{u} + \frac{1}{v} = \frac{1}{f} ]
• The light from the flower penetrates the water droplet, is strongly refracted, and converges at the focal point inside the water droplet. A clear, sharp, and completely upside down, left, and right miniature flower view is accurately presented in the center of the water droplet**!

2. The physical defect of pure water collapse: the secret recipe of medical glycerin (Glycerin) golden ratio

Beginners who spray pure tap water on flowers and plants often encounter the embarrassment of the water droplets flattening and collapsing, or even sliding down the leaves as soon as they are sprayed:

• Insufficient surface tension and too fast evaporation:
• The surface tension of pure water is low, and the contact angle on the waxy surface of plant cuticles is small, and it is easy to spread and form flat water spots; and under the baking of high-power flashlights in the studio, tiny water droplets evaporate and shrink within a few minutes.
• The chemical magic of medical grade pure glycerin (glycerin anhydrous):
• Glycerin has extremely viscous high viscosity coefficient, huge molecular cohesion and strong hygroscopic and anti-evaporation properties.
• Golden blending ratio and water application techniques:
• Ultimate Golden Ratio (1:1 Formula): Pour 50% pure medical glycerin + 50% pure distilled water into a micro spray bottle and shake vigorously;
• Amazing effect: The prepared droplets have extremely high surface tension and can be condensed into nearly spherical tall and full beads, which can hang on filaments or leaf tips for several hours without moving at all and never collapse;
• Fixed-point water application tool: Use a very thin medical insulin syringe or the tip of a pin to dip a drop of micron-level glycerin water at a time and gently touch it on the edge of the flower stem. The water droplets will instantly absorb into a perfect crystal gem.

3. Spatial distance alignment and geometric linear parallax fine-tuning

In order for the flower to be perfectly centered inside the water drop, the spatial geometric axes of the three must be absolutely coaxial:

1. Iron law of three points and one line: The center of the camera sensor -> the center of the water droplet sphere -> the center of the background flower, the three must form an absolutely straight parallel laser axis in space.
2. The placement of flowers in the background (an upside-down mystery):

• Since water droplet imaging has the optical property of “upside down”;
• If you want to see a delicate flower blooming upright in the water droplet, then the real flower you place in the background must be deliberately placed vertically upside down with its big head down!
• After the secondary inverted refraction of the convex lens of the water drop, the miniature image inside the water drop will miraculously flip into a graceful and forward-facing flower posture!

3. Golden ratio of distance: The distance between the water droplets and the front group of the camera lens is usually only 10cm15cm (1:1 macro); while the distance between the background flowers and the water droplets is recommended to be kept at 8cm12cm, so that the refracted flowers fill exactly 80% of the diameter of the water droplets, giving the strongest visual impact.

4. Dual flash lighting and depth of field stack practical specifications

• Dual lights independently control separate lighting (Key & Background Light):
• Group A background light (lighting flowers): Add a small diffuser to strongly illuminate the real flowers in the background from the oblique side, ensuring that the colors of the flowers are extremely bright and highly saturated, and providing an abundant source of high-contrast photons for the refraction of water droplets;
• Group B main light (slightly brightening the edge of the water droplet): Add a snoot behind the side of the water droplet to slightly outline the outline of the water droplet. Note that the power must be 1.5 stops weaker than the background light. Do not directly shine the front of the water droplet to destroy the internal mirror contrast.
• Focus Plane and Depth of Field Stacking:
• Even if you zoom down to f/16 under macro, the depth of field is only 0.5 mm. When the shell of the water droplet is clear, the flowers refracted inside are often blurred;
• Focus Step Stack: Use a macro gear gimbal or in-camera depth-of-field bracketing to focus from the water film on the outer edge of the water droplet, shoot 8~15 slices in steps of 0.1mm, and then stack and synthesize them in Helicon Focus to obtain a shocking microscopic micro-sculpture of the entire water droplet and even the internal refracted stamen panorama!

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