Water surface and glass reflection photography (Reflections): polarization angle control, symmetrical composition and contrast between virtual and real

1. Physical basis of water surface reflection and Brewster's Angle

When light shines on the surface of non-metallic dielectrics such as water or glass, part of it is refracted into the medium, and the other part is reflected back into the air, and the reflected light is strong linearly polarized light:

1. Brewster angle polarization peak:

• The refractive index of water is about 1.33, and its Brewster angle is about 53° (relative to the normal to the water surface, that is, the angle between the line of sight and the horizontal water surface is about 37°).
• Near this incident angle, almost 100% of the reflected light from the water surface is polarized light, and the reflection effect is the most severe. It is also the most sensitive physical critical point for polarizer extinction or light enhancement.

2. Breeze ripples and still water mirror:

• Specular reflection requires stable surface tension of water molecules. The moment the sun just rises in the morning, the wind is usually at its lowest, making it a golden window for photographing the fully symmetrical reflections of natural water bodies, the "mirror of the sky." Shallow puddles on city streets after rain are shallow in depth (water depth 2-5mm) and are minimally disturbed by wind, making them the easiest to form extremely sharp and perfect reflections.

2. Reverse use strategy of CPL circular polarizer

Most photography tutorials only mention "use CPL to eliminate reflections and see clearly underwater", but in reflection photography, CPL has the exact opposite duality of creativity:

1. Maximize the reflection contrast:

• Rotate the CPL adjustment ring to be orthogonal to the polarization direction, allowing the maximum amount of surface-reflected polarized light to pass through, and at the same time greatly suppressing the turbid light transmitted from the water body, making the reflection of the building reflected on the water surface clearer and brighter, as eye-catching as a chrome mirror.

2. Multiple exposure textures interweaving reality and reality (window photography):

• When photographing urban street window glass, fine-tune the CPL rotating ring to "translucent and semi-reflective" (approximately 45-degree position).
• Effect: The display of model props inside the window perfectly overlaps with the bustling street crowds and traffic highlights reflected on the glass surface, directly presenting a surreal urban narrative like a double exposure in a single photo.

3. Ground-Level perspective doubling method

1. The optical axis of the lens is close to the water surface (5cm limit camera position):

• When shooting a shallow puddle while standing and looking down, the projected area of the reflection in the puddle is only a small corner of the screen, making it look stingy and cramped.
• Turn over the camera LCD screen and place the body upside down or the front of the lens flat to only 2-5 cm from the water.
• Optical illusion geometric stretching: The camera position close to the ground will make the close-up view of the puddle spread forward with a huge perspective ratio. The reflection on the ground and the real building are visually equally matched, forming a breathtaking 1:1 up and down symmetrical mirror world.

2. Depth of field coverage and focus point selection (aperture f/8 ~ f/11):

• Laws of physical optics: The visual focus depth of the virtual image on the water surface is not on the water surface itself, but on the projection equivalent distance of "water surface distance + real scene distance"!
• If you focus on the dirt and stones at the edge of the puddle, the reflection in the distance will be blurry.
• Correct focus: Place the single-point focus directly on the doors and windows of the reflected building in the water, and shrink the aperture to f/8 or f/11 to ensure that the large depth of field covers both the ground texture and the reflection structure.

4. Abstract expression of dynamic water surface microwave and slow door drawing

1. High-speed shutter (1/1000s) solidified water droplet refraction: The concentric water wave rings stirred up by raindrops on the water surface can break the static reflection into a geometric dispersion pattern with a pop art feel.
2. Slow door light reduction (ND filter 2s ~ 15s) turns motion into stillness: In the environment of flowing streams or rivers and sea waves, install an ND64 or ND1000 filter for long exposure. The small waves on the water surface are completely smoothed and fogged by the long exposure into a silk-like flat mirror surface, and the originally broken reflections are reunited into hazy and dreamy oil painting-like color blocks.

---