Depth of focus and depth of field of the shooting lens
We know that in the actual focusing process of industrial lenses, when we manually focus on the plane of the object, we gently rotate the focus ring to the left and right. Sometimes we find that the image is still clear within a certain range, and when the clarity of the image exceeds a certain range, the clarity of the image decreases. This involves two terms, depth of field and depth of focus. Ruicheng Optoelectronics will introduce depth of field and depth of field respectively.
Before we talk about depth of field, we need to understand the concepts of focus and dispersion circle: when light parallel to the optical axis is incident into a convex lens, the ideal lens should have all the light gathered behind a point and then dispersed in a conical shape, which is called the focus.
A diffusion circle refers to the phenomenon where light begins to gather and diffuse before and after focusing, causing the image of a point to become blurry and forming an enlarged circle, known as a diffusion circle.
So what is the depth of the field? The depth of the field of view refers to the allowable dispersion circle before and after focusing, and the distance between two discrete circles is called the depth of the field, which is the distance between the object before and after focusing. The image still has a clear range, which is the depth of the field.
Depth of focus refers to the distance that the focal point (focal plane) is allowed to move along the optical axis of the lens while maintaining image clarity.
The difference between depth of focus and depth of field
1. The meaning is different: the depth of the field is the vertical and long-distance distance that produces clear images in the scene; Depth of focus is the distance that the focal plane of an image can move.
2. When the camera distance decreases, the focal length increases and the depth of field decreases; On the contrary, as the camera distance increases, the depth of field increases and the focal length decreases.
3. When the imaging ratio of the scene increases (such as using telephoto lenses, shortening viewing distances, etc.), the depth of field decreases and the depth of focus increases. And when the imaging ratio of the scene decreases (such as using short focal length lenses, increasing viewing distance, etc.), it decreases.
4. When the aperture decreases, the depth of field and focal depth increase; When the aperture increases, the depth of field and depth of focus decrease.
5. As the requirement for image clarity decreases, the depth of field and focal length increase. When the requirement for image clarity increases, both the depth of field and the depth of focus decrease.
6. Depth of field is largely related to the reproduction of the subject being photographed, while focal length is largely related to the camera's production.
The practical value of focal depth
Before shooting, the maximum aperture should be focused (according to visual image engineers, this not only increases the brightness of the image, but also reduces the depth of focus, which helps with precise focusing). After accurate focusing, the aperture should be adjusted to the gear required for shooting.
Before we talk about depth of field, we need to understand the concepts of focus and dispersion circle: when light parallel to the optical axis is incident into a convex lens, the ideal lens should have all the light gathered behind a point and then dispersed in a conical shape, which is called the focus.
A diffusion circle refers to the phenomenon where light begins to gather and diffuse before and after focusing, causing the image of a point to become blurry and forming an enlarged circle, known as a diffusion circle.
So what is the depth of the field? The depth of the field of view refers to the allowable dispersion circle before and after focusing, and the distance between two discrete circles is called the depth of the field, which is the distance between the object before and after focusing. The image still has a clear range, which is the depth of the field.
Depth of focus refers to the distance that the focal point (focal plane) is allowed to move along the optical axis of the lens while maintaining image clarity.
The difference between depth of focus and depth of field
1. The meaning is different: the depth of the field is the vertical and long-distance distance that produces clear images in the scene; Depth of focus is the distance that the focal plane of an image can move.
2. When the camera distance decreases, the focal length increases and the depth of field decreases; On the contrary, as the camera distance increases, the depth of field increases and the focal length decreases.
3. When the imaging ratio of the scene increases (such as using telephoto lenses, shortening viewing distances, etc.), the depth of field decreases and the depth of focus increases. And when the imaging ratio of the scene decreases (such as using short focal length lenses, increasing viewing distance, etc.), it decreases.
4. When the aperture decreases, the depth of field and focal depth increase; When the aperture increases, the depth of field and depth of focus decrease.
5. As the requirement for image clarity decreases, the depth of field and focal length increase. When the requirement for image clarity increases, both the depth of field and the depth of focus decrease.
6. Depth of field is largely related to the reproduction of the subject being photographed, while focal length is largely related to the camera's production.
The practical value of focal depth
Before shooting, the maximum aperture should be focused (according to visual image engineers, this not only increases the brightness of the image, but also reduces the depth of focus, which helps with precise focusing). After accurate focusing, the aperture should be adjusted to the gear required for shooting.