What is the letter of the aperture?

Question 1: What English letter is used to indicate the adjustment of the aperture in a digital camera? It is denoted by f .. The following is the definition of aperture:

The English name of Aperture is aperture. Aperture is a device used to control the amount of light entering the photosensitive surface of the fuselage through the lens. Usually in the camera. The aperture values F2.8, F8 and F 16 are the aperture "coefficients", which are relative apertures, not the physical aperture of the aperture, and are related to the physical aperture of the aperture and the distance from the lens to the photosensitive device (film or CCD or CMOS).

We use the f value to represent the aperture size. Aperture f value = lens focal length/lens aperture diameter According to the above formula, to achieve the same aperture f value, the aperture of a long focal length lens is larger than that of a short focal length lens.

When the physical aperture of the aperture is constant, the farther the lens center is from the photosensitive device, the smaller the F number is. On the contrary, the closer the lens center is to the photosensitive device, the higher the light density reaching the photosensitive device through the aperture and the larger the F number. The complete series of aperture values are as follows: F 1, F 1.4, F2…… ... ...

The smaller the f value of the aperture, the more light enters in the same unit time, and the light quantity of the upper level is exactly twice that of the lower level. For example, if the aperture is adjusted from F8 to F5.6, the amount of light will be doubled. We also say that the aperture is enlarged by one level. Most non-professional digital camera lenses have short focal length and small physical aperture, and the physical aperture of the aperture is already very small in F8. If it continues to shrink, optical phenomena such as diffraction will appear, which will affect imaging. Therefore, generally speaking, the minimum aperture of a non-professional digital camera is from F8 to F 1 1, while the photosensitive device of a professional digital camera has a large area, and the lens is far away from the photosensitive device, so the aperture value can be very small. For consumer digital cameras, the aperture f value is often between F2.8-F 16. In addition, many digital cameras can adjust the aperture by 1/3.

Question 2: What letters are used for focal length, aperture and zoom: **mm?

Aperture: f*

Zoom: * *-* *-* * mm

Where * * represents a specific value.

Question 3: What letter is used for camera aperture priority and shutter priority to indicate shutter priority? The shutter priority of Canon and Pentax is TV, and Nikon is S.

Aperture priority: AV and a files.

In addition to the automatic mode, advanced digital cameras usually have two options: aperture priority AV and shutter priority TV, so that you can decide a certain aperture value or a certain shutter value in some occasions, and then match the appropriate shutter or aperture respectively to present different depth of field (sharpness) or effects of the picture.

Question 4: What do the letters on the lens of SLR cameras mean? Lens recognition

Logo interpretation of digital SLR lens

Facing the digital SLR cameras with different brands and many lens groups, how to choose from the actual use situation can achieve the best image finished product effect. As we all know, this "tool" needs to be "recognized" first, so there is the problem of how to interpret the lens logo of digital SLR camera.

Common sense of explanation

Whether it is the lens used by traditional film SLR cameras or the lens used by digital SLR cameras, the lens identification text basically contains information such as lens attributes, focal length parameters, aperture parameters and characteristics.

In detail, the above four points can be summarized as follows:

Lens properties: usually indicate whether the lens is AF mount or EF mount, and usually include some lens type identification;

Focal length parameter: indicates the focal length range of the lens, in mm;

Aperture parameter: indicates the maximum aperture coefficient of the lens, and some lenses also indicate the minimum aperture coefficient of the lens;

Features: It represents the characteristic technology adopted by the lens. This is also the content to be explained later.

The usual format of this information is shown in the above figure, in which we can get the information of "Canon Zoom Lens EF-S10-22mm1:3.5-4.5 USM". This information enables us to interpret the complete parameters of this lens: Canon original EF-S electronic bayonet automatic zoom lens; Focus range 10 -22mm (super wide angle 2 times zoom); The maximum aperture coefficient is 3.5-4.5; USM ultrasonic motor is adopted.

In addition, the version number is also one of the common logo text contents, indicating which generation of products the lens belongs to in the same specification lens.

Detailed identification

Among the SLR lenses that junior photographers contact more, Canon and Nikon account for the majority, and other well-known brands such as Pentax, Sigma, Tokina and Tamron also have their own worlds. The following will systematically introduce the logo meaning of the above brand lens.

Canon (Canon)

Al: Aspheric lens. Canon lens marked with the word "AL" is not a spherical lens in design. The purpose of this is to reduce the number of lenses, reduce the weight and volume, and provide better optical performance. Aspheric lenses are generally used to solve the problems of glare and edge deformation in wide-angle and zoom lenses. In addition, the optical quality can also be improved in telephoto lenses. Pentax's lens also uses "AL" to indicate the use of an aspherical lens.

DO: diffractive optics. Canon lens marked with the word "DO" is equipped with multilayer diffractive optical lens, which has the characteristics of fluorite and aspheric lens. Simply understand, this "DO" logo generally belongs to high-end Canon lenses.

EF: electronic bayonet, English full name electronic focusing. This is an electronic autofocus lens specially used by Canon for its EOS series cameras, and it is our common Canon lens. It can be applied to Canon SLR and DSLR in Quan Huafu and APS formats, and its notable feature is that there is a red dot at the interface to align the fuselage card position.

EF-S: Electronic bayonet of digital SLR in APS format. This is an electronic lens specially designed by Canon for its APS digital SLR camera, and it is also our common Canon lens. It can only be applied to Canon DSLR in APS format, and its notable feature is that there is a white square at the interface for aligning the card position of the fuselage.

EMD: electromagnetic diaphragm, which is the full name of electromagnetic diaphragm in English. The lens with this technology can electronically control the opening and closing of the aperture.

Float: floating function, English full name Floating System. This is Canon's lens design ... >>

Question 5: What letter is used instead of abc for the button of shutter sensitivity aperture on the camera?

Question 6: What is the significance of aperture in photography? 1, concept

Aperture is a device used to control the amount of light entering the photosensitive surface of the fuselage through the lens, usually in the lens. For the manufactured lens, the diameter of the lens cannot be changed at will, but the luminous flux of the lens can be controlled by adding a polygon or circular aperture grating with variable area inside the lens. This device is called an aperture.

2. Calculation method

The aperture size is expressed by f value.

Aperture f value = lens focal length/lens aperture diameter

As can be seen from the above formula, to achieve the same aperture f value, the aperture of a long focal length lens is larger than that of a short focal length lens.

3. Aperture function

(1) can adjust the amount of light entering the lens. When taking pictures, if the light is strong, you should narrow the aperture, if the light is dark, you should open the aperture. That is to say, the smaller the F value (other parameters remain unchanged), the more favorable it is for shooting at night. The adjusting ring on the rotating lens or the knob on the digital camera body is used to adjust the aperture size.

(2) Aperture is the most important factor to determine the depth of field, with large aperture (small aperture value), small depth of field, small aperture (large aperture value) and large depth of field!

Question 7: What is aperture and what are its types? The aperture is a very important parameter in photography. Before, our photography series from scratch also talked about aperture priority mode, but knowing aperture priority does not mean knowing what aperture is. In fact, the aperture is still very learned. Today, let's talk about what you have to know about aperture. What is the aperture? Simply put, the aperture is a parameter indicating the brightness of the lens. I think this is quite different from what everyone knows. Speaking of aperture, we should first introduce aperture. The hole in the aperture blade is the aperture. There is a device in the lens that can change its aperture by changing the position of the aperture blade. This aperture is the device that controls the light passing ability in the lens. For a lens, the larger the aperture, the greater the ability of light to pass through. However, we know that all lenses have their own focal lengths. For the same aperture, the longer the focal length, the narrower the viewing angle, and the smaller the total amount of light obtained in the viewing angle. Therefore, it only has good light passing ability, but due to the influence of telephoto, the total light input is small and the lens is not bright enough. Aperture value F= focal length/aperture focal length unchanged. The larger the aperture, the smaller the aperture value and the brighter the lens. The aperture is constant, the shorter the focal length, the smaller the aperture value and the brighter the lens. Therefore, the aperture is the most objective parameter to express the brightness of the lens. You need to know the aperture size, but in practice, aperture and aperture value are not the same concept. When asked about the exact parameters, aperture can be used as the abbreviation of aperture value. When communicating, the aperture often represents the size of the aperture. This involves an industry habit and can only be memorized. The larger the aperture, the smaller the aperture value. But when you ask what the aperture is, you usually ask what the aperture value is. Simply put, when used as an aperture value, F2.8 is greater than F8. Schematic diagram of aperture size A lens with a large aperture has good light transmittance and brightness, which is beneficial for photographers to take a view and focus on the camera. If the standard is F 1.0, the aperture value is one step every 1.4 times. The luminous flux of each aperture is 2 times different, because the aperture value is the ratio of the aperture diameter to the focal length, and the luminous flux is determined by the aperture area. The square of 1.445438+04 is exactly 2 times. On the other hand, according to the pinhole imaging principle of the same focal length, the smaller the aperture, the clearer the out-of-plane imaging of the focus, and the larger the aperture, the more blurred the out-of-plane imaging of the focus. In fact, the blur here is what is usually called background blur, which is what photographers call the depth of the scene. Different apertures produce different depth of field and have different uses. When shooting portraits, we often want to separate the portraits from the background. Shallow depth of field can achieve this goal, so you need to shoot with a large aperture. When shooting scenery, we want to get a clear picture from far to near, so we need a deep depth of field and shoot with a small aperture. Aperture Type The simplest camera with a fixed aperture only has a fixed aperture with a circular hole-waterhouse aperture. The original variable aperture is just a series of circular holes of different sizes, arranged around a disk with a central axis; Rotating the disc can move the circular hole with appropriate size to the optical axis, thus controlling the aperture. John is in the middle of the nineteenth book? Walter Hauser invented this kind of aperture. Mobile phones mostly use fixed aperture cat's eye aperture. The cat's eye aperture consists of a metal plate with an oval or diamond hole in the middle, which is divided into two parts. Two pieces of metal with semi-elliptical or semi-diamond holes are arranged in rows, and move relatively to form cat's eye holes. Cat's eye aperture is mostly used for simple cameras. Iris-shaped aperture is composed of a plurality of overlapping arc-shaped thin metal blades, and the size of the central circular hole can be changed by the clutch of the blades. Some cameras can change the aperture of the diaphragm by rotating the ring on the lens barrel, while others automatically change the aperture of the diaphragm by controlling the micro-motor through the microprocessor chip. Arc thin metal blades up to 18. The more arc-shaped thin metal blades, the closer the aperture is to a circle. By designing the shape of thin metal blades by computer, a nearly circular aperture can be obtained with only six thin metal blades. Instantaneous aperture The aperture of a SLR camera is an instantaneous aperture, which will be reduced to a predetermined size only when the shutter is opened. Usually the aperture is at the maximum position. SLR lenses use this kind of double shutter aperture. Some simple cameras have the function of shutter. Most of these double-shutter apertures are cat-eye apertures with double blades, which are different from simple cat-eye apertures: the double-shutter apertures are usually completely closed. Most large and medium-sized cameras are inter-mirror shutters. At the moment when the shutter is pressed, the double-blade aperture is opened to a predetermined aperture, and this is maintained ... >; & gt

Question 8: What do the letters on the lens stand for? Different manufacturers or letters on different lenses have different meanings and cannot be generalized. Generally, the number before "mm" represents the focal segment.

Take EF-S 17-55 F2.8 IS USM as an example. EF-S stands for Canon EF bayonet, specially designed for APS frame machine. 17-55mm represents the maximum wide-angle focal length 17mm and the maximum focal length is 55mm, which is the zoom lens. F2.8 stands for the maximum aperture of 2.8, which can be used at both telephoto and wide-angle ends.

Question 9: How to express the aperture coefficient in photography? The standard representation should be lowercase letter f/ 1.2.