Practical shorthand formula

Photometric determination

Photometry measures the brightness of the picture and provides exposure parameters. There are three main measurement modes: evaluation measurement, central key measurement and point measurement.

Evaluation photometry

Evaluation photometry is the most commonly used photometry method, and its photometry logic is to average each area one by one and take the average value as the reasonable exposure value of the whole picture. It is safer for friends who don't know about photometry to choose evaluation photometry.

Central key photometry

Center focus photometry is to measure the area around 1/3 in the center of the picture. When shooting, the subject is usually placed in the center, which can ensure the correct exposure of the subject and avoid the influence of areas outside the center on the exposure results.

Spot photometry

Measure the 3% area of the picture. When the subject is not in the center, directly measure the light at the subject to ensure the accurate exposure of the subject. Spot measurement is the most accurate way, and the linkage function combined with spot measurement is the most perfect shooting method. Otherwise, after metering, lock the exposure and then make composition and focus shooting.

hole

Aperture is a device used to control the amount of light entering the camera. When we take pictures, the first threshold for light to enter the camera is the aperture. This hole is like a faucet valve. The bigger the valve is opened, the more water will flow out at the same time. On the contrary, the less. In the camera, the aperture is expressed in the form of "F+ number", and the larger the number after f, the smaller the aperture; The smaller the number after f, the larger the aperture.

shutter

Shutter is indicated by "S" on the camera, which is mainly used to control the exposure time. Shutters are generally divided into high-speed shutters and slow doors. The faster the shutter speed, the darker the picture will be, which is used to capture and freeze. The slower the shutter speed, the brighter the picture will be, which is used to record the motion trajectory.

International Organization for Standardization (ISO)

ISO sensitivity is simply the sensitivity of photosensitive elements to light. The higher the ISO, the more sensitive the photosensitive element is to light. The more exposure, the brighter the picture and the higher the noise, which will affect the picture quality. On the contrary, the lower the ISO, the darker the picture, the less noise, the clearer and more textured it is.

focal distance

The focal length of a lens is generally in millimeters (mm), which can be simply understood as:

1. The shorter the focal length (wide-angle lens): the smaller the number, the larger the field of view and the wider the framing range, and the more scenes shot, the smaller the proportion of the scenes in the picture.

2. The longer the focal length (telephoto lens): the larger the number, the smaller the field of view, the narrower the framing range, and the fewer scenes photographed, the greater the proportion of scenes in the picture.

Single autofocus

AF-S single autofocus mode, the camera immediately stops focusing and locks the focus after completing a focusing job, and the focus area will not change due to the movement of the subject. According to the characteristics of single autofocus, it is often used to shoot relatively static subjects, such as still life props, environmental scenery, portraits and so on.

Continuous autofocus

Aperture priority mode is semi-manual mode. When using this mode, you choose the aperture you want, and the camera chooses the appropriate shutter speed to realize the correct exposure of the photo. To switch the camera to aperture priority, turn the dial at the top of the camera to "A".

Intelligent autofocus

Intelligent autofocus means that the camera can automatically select the mode according to the state (still or moving) of the subject, and select single autofocus when the subject is still and continuous autofocus when the subject is moving. Usage scene: children and pets, represented by AF-A.

change colour

It is caused by lens scattering. Due to the wavelength difference of different colors of light, blurred or obvious color edges (red, green, blue, yellow, purple, magenta) may appear around the objects in the image, especially in the case of high contrast, which is called chromatic aberration.

Bloody eyes

In the dark scene, turn on the flash to fill the light, while in the dark condition, in order to see things around, people's pupils will be enlarged a lot. Sudden strong light will make the pupil shrink too late, all the light will enter the human eye, and then the light reflected by the blood vessels on the iris will enter the camera lens, making the human eye in the photo appear red, which is what we call "red eye".

shade cloth

It is used to block the sun and the sun, and it is functional. It is usually used with other fabrics to cover articles and avoid contact with strong light, which has the function of blocking strong light and ultraviolet rays.

lens flare

Strong non-imaging light from the sun or artificial light source will actually produce lens glare after entering the lens and then hitting the digital sensor of the camera. When light bounces around the camera's sensor, it will produce unwanted objects. Those "objects" are what we call lens halos.

depth of field

When taking a picture with a camera, the clear part of the picture is the depth of field. Classification of depth of field:

1. Shallow depth of field: it is mostly used to shoot portraits and highlight the main body of the characters.

2. Large depth of field: mostly used for natural scenery, highlighting details.

Three elements of depth of field: aperture, focal length and shooting distance.

Depth of field formula:

1. The larger the aperture, the shallower the depth of field. ?

2. The longer the focal length, the shallower the depth of field.

3. The closer the shooting distance, the shallower the depth of field.

Exposure; expose

That is, "photo brightness", exposure is mainly affected by aperture, shutter and sensitivity. We can control the brightness of photos by controlling the three elements of exposure. In addition, it can be adjusted by adjusting exposure compensation and focusing mode.

Out of focus

Out-of-focus is the phenomenon that the focus determined by SLR camera through autofocus system deviates from the actual focus. Paying attention to the accuracy of focusing is one of the important factors to evaluate whether a photo is scrapped or not. Accurate focusing can ensure that the photos are clear. And one of the most important factors is out of focus.

Overexposure

In photography, exposure is achieved by adjusting the aperture size and shutter speed. If the scene in the photo is too bright, the bright part has no layers and details, which is overexposed. If the environment is too dark and the photos are dark and can't truly reflect the color of the scene, it is underexposure.

Front lighting

The light coming from the back of the camera and projecting the object from the front is called smooth light. Features: Most subjects are direct, with small shadow area and clear tone. The contrast between light and shade formed by this kind of light is weak, and the stereoscopic effect of the object is not reflected by illumination light, but by its own ups and downs, so the stereoscopic effect is weak.

Backlighting

A method of using light in photography, that is, shooting light from the back of the object to the camera lens. This method can clearly outline the outline of the object, or show the transparent body more prominently.

direct light

Direct light means that the sun shines directly on the surface of an object without obstacles. We call it direct light. The most obvious performance is that the sun will form a shadow on the ground after it shines on you, so this light is direct light.

Shading plate/cloth

When taking pictures, it is used in front of the camera lens to block excess light and prevent lens glare. Most of them are made of metal, plastic and other materials, and their shapes are mostly flower-shaped and cylindrical. Using the hood can effectively prevent the interference light around the lens from entering the lens, and improve the clarity and color reproduction of imaging.