CHANCCTV-OPTICSLENS

In the fields of photography and optics, aperture is a very important concept. It is a device inside the lens used to control the amount of light passing through. Simply put, the aperture is like the pupil of the human eye; it can adjust its size according to the intensity of ambient light, thereby controlling the amount of light entering the eye. Aperture is one of the core concepts for beginners in photography, and in this article, we will explore its definition and function. 1. Definition of aperture (1) Effective caliber The diameter of the light beam when parallel light rays from an infinitely distant source pass through the front lens of a camera is called the lens caliber. This actually represents the basic light-gathering capacity of the lens and is therefore called the effective caliber. We can usually see markings similar to "[1:2 f/58mm]" on the front of a camera lens. This indicates the lens caliber and focal length. It shows that the ratio of the lens aperture t...

1. What is relative illuminance? The edges of the object appear noticeably darker; can this be improved? Today we'll look at this parameter—relative illumination. Definition: Illuminance is the degree of brightness exhibited by an object or surface when illuminated by a light source. Relative illumination refers to the ratio of the brightness at the edge of the field of view to the brightness at the center, expressed as a percentage. It is a parameter that characterizes the optical phenomenon caused by a portion of the light entering the lens being blocked or reduced. In optical design, the relative illumination curve provides a visual representation of the brightness at various positions in the field of view relative to the center. 2. What factors affect relative illuminance? (1) Fourth p ower of c osine Law The brightness at the edge of the field of view decreases proportionally, and this is related to the fourth power of the cosine of the viewing angle. The f ourth p ower of c o...

Varifocal  lenses have the characteristic of variable focal length. Compared to fixed focus  lenses, they can cover multiple focal lengths without the need for frequent lens changes, making them suitable for shooting situations that require quick adjustments to composition and handling complex scenes, such as wedding photography and outdoor portrait photography. When using varifocal  lenses to shoot portraits, photographers can take advantage of their versatility and flexibility to enhance the shooting results. Next, we will learn together about the usage techniques and precautions of varifocal  lenses, and learn how to properly shoot portraits. 1. Choose the appropriate focal length The medium telephoto range (focal length 50-135mm) of a varifocal  lens is ideal for portrait photography, especially 85mm and 135mm, which are classic focal lengths for portraits. They are suitable for close-up portraits, compressing spatial perspective, blurring the background, a...

Short   focus lenses have a short focal length, offering a wide field of view and unique perspective effects, making them suitable for shooting various types of photos. Below are some common types of photos that are well-suited for short-focus lenses: 1. Landscape photography Short foc us  lenses are ideal for shooting landscapes. Their wide field of view can capture a wider scene and perfectly capture magnificent natural landscapes, showcasing the awe-inspiring grandeur of mountains, grasslands, oceans, and other magnificent scenery, making the viewer feel as if they are in the picture. 2. Architectural photography Short focus lenses are also suitable for photographing buildings, as they can capture the entire structure within a limited space, reducing compositional limitations caused by insufficient distance. For example, when photographing interior environments such as rooms, lobbies, and hotels, short-focus lenses can maximize the sense of spaciousness and layout. It's im...

What Are The Characteristics And Applications of Large Depth-of-Field Industrial Lenses? : In industrial environments, it is often necessary to clearly see objects at different distances. To avoid affecting detection accuracy, specially designed industrial lenses with a large depth of field are typically used.

When shooting with a wide   angle lens , balancing the proportions of the foreground and background is one of the crucial aspects of composition, and is key to enhancing the depth and harmony of the image. Because wide-angle lenses have a wide field of view and strong perspective, they can easily make the foreground appear very large while the background appears very small. Therefore, photographers need to use various methods to harmonize the relationship between the foreground and background to achieve visual harmony and balance. Hopefully, the following tips and suggestions will help you: 1. Close to the foreground Boldly and truly getting closer to the foreground elements you want to emphasize is the most fundamental way to balance a wide-angle composition; even a movement of just a few centimeters can make a huge difference. When you get closer to the foreground, its proportion in the frame increases dramatically, while the background, although "pushed further away," stil...

1. The definition and function of a   d iaphragm The brightness of an image depends on the luminous flux passing through the optical system. The edges of optical elements or specially designed openings (d iaphragm ) in the system serve to limit the cross-section of the light beam, thus controlling the flow of light energy. Since any optical system is inherently diffraction-limited, and its resolution is limited by the system's d iaphragm , every optical system must have a primary limiting aperture (the d iaphragm ). Not every lens edge acts as an effective d iaphragm , and additional d iaphragm s are often added to improve image quality. Therefore, a general method is needed to determine which element in a complex optical system (such as lenses, mirrors, and aperture screens) actually acts as the critical component limiting the incident light beam — that is, the effective d iaphragm . Among all the d iaphragm , the one that most effectively limits the incident light beam is called...