The basics of photography


If you are a beginner in the art of photography, I want to come to your aid with the experience I gained during my career as a photographer. I learned everything from Youtube, the internet, articles. I want to share what I know and what mistakes I've made so far, so maybe I'll save you some mistakes and wasted time. Besides, you can become a little skeptical about your photos and demoralize, because it's not exactly like want .

Well, let's get started.

From my point of view, if you don't master these things, you can't really manage to take photos on another level.


ISO

What is ISO?


ISO (International Organization for Standardization) refers to the standard oval granted for a certain sensitivity of the photosensitive material.

Sensitivity is a characteristic of the sensor (sensor) or photo film that determines the amount of light we need to have a correct exposure.

The best known values ​​are: 25, 50, 100, 200, 400, 800, 1600, 3200 and 6400.

In ascending order, each ISO value is twice as large as the previous one.

Example: ISO 800 is 2x more sensitive than ISO 400 and only half as sensitive as ISO1600.

Digital devices also allow us to set / choose intermediate ISO values. Example: ISO 80, ISO 640 etc.

To properly expose, the camera sensor (the sensor for digital cameras) needs an amount of reverse light proportional to the sensitivity.

Thus, for example for ISO 100 information we will need more light but also a very good image quality, while in the case of higher sensitivity values, we will need a smaller amount of light, but we will risk the appearance of noise.


Practical tip: Use high sensitivity when you do not have a tripod, flash, or other image enhancement option.

Example: the case of concerts, where if we do not have a flash, we can not use the tripod version, as a long exposure time would lead to the playback of the moving subject, and not "frozen".

WHITE BALANCE

White balance (WB) is a function of digital cameras through which they process, determining the required proportion of each fundamental color (RGB) so that the subject is reproduced all white in the image if it is white.

The 3 main colors (RGB-red, green, blue) exist in the light source in varying proportions, depending on the color temperature. When it is raised, blue will predominate. When this is excused, red will predominate. To the human eye, a white object can look white regardless of the type of illumination. For cameras, however, this is more complicated and this is where the white balance functions come into play. Unlike the human eye, which adapts quickly to changes in intensity and color, digital sensors perceive light sources differently and often need to be "helped". The reason is that light has a certain color temperature, depending on its origin. For example, the light at noon on a sunny sky is 5200-5500 degrees Kelvin, the cloudy sky gives a temperature of 6000-6500 degrees Kelvin, while a classic light bulb provides light with a color temperature between 2500 and 3300 degrees Kelvin. The color temperature in the shade can reach 10000 degrees, Kelvin.

The settings available for white balance are:

Auto: White balance is performed automatically by the camera; their performance has improved considerably over time, but advanced users prefer to control the process themselves for consistent results.


Incandescent / Tungsten


(with a value of 2700K) one of the most problematic for the automatic measuring system, will be selected preferably when shooting under incandescent light sources, which include halogen. Be careful, however, that these light sources do not have exactly the same color temperature, so there is a possibility that the color tones may differ.

Fluorescent: (with a value of 4200K) setting used, as expected, in the case of fluorescent light sources, ie neon type. If in the case of incandescent light the color tones turn to yellow, in the case of fluorescent ones the tendency is towards green.

Daylight / Sunny: this setting is of course suitable for outdoor frames during the day.

Flash: used when the flash is the main light in a photo. This is also a valid setting for studio flashes, although the exact temperature may vary.

Cloudy: setting for days with cloudy, overcast or gloomy skies.

Shade: suitable setting when the sunlight is strong, but you are in a shady area.


DIAPHRAGM AND EXPOSURE

The aperture of a lens, also known as the "aperture" or "iris" is an ingenious piece of mechanical engineering that provides a variable-size aperture in the optical path and can be used to control the amount of light passing through the lens. . Aperture and shutter speed are the two primary means of controlling exposure: for a given shutter speed, dimming will require a larger aperture to allow more light to reach the image sensor plane, while brighter light will require a smaller aperture to get optimal exposure. Alternatively, you can keep the same aperture setting and change the shutter speed to get similar results. However, the size of the aperture provided by the aperture also determines how "collimated" the light passing through the lens is, and this directly affects the depth of field, so you will need to control both aperture and shutter speed to create images that look like this. as you wish.

"F numbers" or "F stops"

All lenses have a maximum and a minimum aperture, expressed as "F numbers", but the maximum aperture is most often cited in the lens specifications. Take the 35 mm Sony F1.4 G as an example. This is a 35mm F1.4 lens: 35mm is the focal length (we'll get to that later) and F1.4 is the maximum aperture. But what exactly does "F1.4" mean? See the box "Mathematical Calculations of the F-Number" for some technical details, but for a practical understanding, it is enough to know that the smaller F numbers correspond to the larger diaphragms and that F1.4 is approximately the largest maximum aperture you are likely to encounter among general-purpose lenses. Lenses with a maximum aperture of F1.4, F2, or F2.8 are generally considered "fast" or "bright".

The standard F numbers that you will use with the camera lens are, from larger apertures to smaller apertures: 1,4, 2, 2,8, 4, 5,6, 8, 11, 16, 22, and sometimes 32 (for mathematicians, these are all powers of the square root of 2). These are complete stops, but you will also see fractional stops, which correspond to a half or a third of the complete stops. Increasing the aperture size by a complete stop doubles the amount of light that is allowed to pass through the lens. Reducing the aperture size by stopping halves the amount of light reaching the sensor.


EXPOSURE TIME

For a well-exposed image, the camera's sensor must receive a precise amount of light, which is described by sensitivity and does not depend on the lighting conditions of the subject. The amount of light is adjusted by the aperture, which is responsible for the "flow" of light and the exposure time, which obviously determines the time of light action on the sensor. So, the same exposure can be obtained through a larger aperture, so with a lighter aperture in a shorter time or a darker diaphragm in a correspondingly longer time.

Proper exposure from the shooting phase is necessary to avoid or at least minimize further processing of the images taken. Computer processing is time-consuming, and besides, images that require large exposure corrections will ultimately not have the same quality as images that are properly displayed directly from the camera.

If the image is not displayed correctly, it may be underexposed, so it has not received enough light or overexposed if it has received too much light when shooting.


PORTRAITS


In portraits, we are primarily interested in exposure time, as we will photograph moving subjects by hand. The problem is amplified by the use of telephoto lenses, which are much more sensitive to camera shake. Fortunately, a large number of telesoomers have optical stabilization.

However, to have a reasonable success rate for portraits, we will need at least an exposure time of around 1 / 125s.

Only if the subject does not move at all, we can lower the time to 1 / the 60s, with the risk of obtaining images with motion blur.

The short exposure times are also favored by the fact that in most portraits we will want a shallow depth, which is obtained by opening the aperture, using very well the existing light.

We will use the lowest sensitivity that the available light allows us, after setting the exposure time to a reasonable value and opening the aperture near the brightness of the lens.


LANDSCAPES


Lapeisaje we want maximum clarity for a better rendering of the details in the final image.

So we will use the minimum sensitivity of the device, where there is no noise due to signal amplification.

The aperture influences both the sharpness of the image and the depth of field. We will obtain the maximum clarity of the objective at the average diaphragms, around F: 5.6 or 8.0, where most of the aberrations will be much reduced, and the diffraction, characteristic of closed diaphragms, is not manifested yet.

The depth at these apertures is large enough, especially at short focal lengths generally used in landscapes. For example, using a small format camera with a wide lens, say around 20mm, at the F: 8.0 aperture we will have clarity from 1.5m to infinity, focusing at about 3m from the camera.

The exposure time will be determined based on the existing light. If it is too long for safe hand shooting, we will use a tripod or other camera stand, especially if we do not have stabilization in the lens/camera.

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