Optical Domes and Underwater Photography

Underwater photography is an indispensable method for marine research and development and film and television production. However, due to the characteristics of light in water and the particularity of the use environment, glass domes are more and more widely used in underwater optical systems. RZ Optics is a professional manufacturer that produces and processes optical glass domes. Custom glass domes can be produced and coated for your application.

What are the advantages of a glass dome over a parallel plate window?

If a simple transparent parallel flat glass is used to seal and waterproof, the viewing angle of the objective lens will become smaller (the focal length will increase), the magnification will decrease, and the aberration will also change. Distorted and reduced clarity. The glass dome can improve some defects caused by the refraction of the water medium and increase the curvature of the image surface of the objective lens.

How to choose optical materials suitable for underwater environment?

v Compression resistance: The underwater optical system must withstand a certain hydrostatic pressure when working, so that the system can resist the hydrostatic pressure of the working environment without damage.

v Corrosion resistance: due to the elements in the water, temperature, oxygen content, salt content and other factors, the material will be corroded.

Therefore, the selection of optical materials for underwater environments mainly considers pressure resistance and corrosion resistance. Such as BK7, quartz, sapphire, etc.

How does the underwater environment affect imaging?

1. Scattering of light by water

Substances and microorganisms suspended in the water, causing the water to scatter light. The light encounters obstacles in the transmission process, which causes the attenuation of light, changes the imaging distance, makes it difficult to capture images, and affects the imaging quality. Underwater, the object distance of the lens is about 75% of the original object distance.

2. Absorption of light by water

The absorption of light by water can attenuate the intensity of light by four percent per meter.

3. Water and air have different refractive indices

When the imaging light of the underwater target passes through the interface of water-glass shell window-air, it will be refracted, which will bring unfavorable factors such as focusing error, viewing angle error, distortion and chromatic aberration to the underwater optical imaging system. In addition, due to various factors such as water depth and salt content, the refractive index of water changes, which affects the imaging quality.

4. Temperature changes

Due to the large temperature difference between the water surface and the underwater, the water inside the underwater system is easy to condense to form water vapor, which affects the imaging quality.

The optical glass dome is wear-resistant and scratch-resistant, and the optical glass used is pressure-resistant and corrosion-resistant. Its structure can effectively correct the imaging effect. The shape of the glass dome increases the width of the field of view, reduces internal reflection, helps to correct the aberration generated when light passes through two media, and can also obtain images that cannot be captured by the glass window. result.

RZ Optics Co., Ltd. provides you with glass domes with many years of production experience. The material can be BK7, quartz, sapphire and other optical materials suitable for underwater environment. The inside and outside of the dome can be coated with aluminum to reduce aberrations. In addition, it can also provide spherical lenses for use with it, such as plano-concave lenses, plano-convex lenses, bi-concave lenses, bi-convex lenses, and achromatic lenses. If you have any questions and needs, please contact us