The basic parameters of photography have not changed since the good old film days. These are the focal length of the optics, shutter speed, aperture and depth of field, sensitivity, and white balance. It is also worth mentioning the RAW and JPEG file formats. Let's start in order.

1. Focal Length

Technically, focal length is the distance from the optical center of the lens to the camera sensor plane. This parameter is expressed in millimeters (for example, 35 mm, 24 – 70 mm) and determines the field of view of the lens. The shorter the focal length, the wider the field of view of the optics, and vice versa. The scale of objects in the frame depends on the field of view.

Objects in the frame look different at various focal lengths.

The focal length is tightly linked to the size of the camera sensor — the 35mm sensor, installed in full-frame cameras, is used as a reference point. If you have a camera with an APS-C sensor, the focal length needs to be multiplied by the crop factor: usually 1.5x, and for Canon cameras — 1.6x. For mirrorless cameras with a Micro 4/3 sensor, the crop factor is 2x (i.e., a conditional lens Panasonic 42.5mm f/1.7 ASPH OIS will have an equivalent focal length of 85 mm).

The wider the focal length of the lens, the more can fit into the frame. And the longer it is, the larger the objects will appear in the photo. Conditionally, focal lengths can be divided into the following subcategories:

  • approximately up to 18 mm — ultra-wide-angle optics; when shooting, the maximum surrounding space fits into the frame, but the picture will have characteristic geometric distortions (the center of the scene seems to "protrude" towards the viewer, while the edges are visually "stretched" into the distance);
  • from 18 to 35 mm — wide-angle optics; this range is great for shooting landscapes, architecture, interiors;
  • from 35 mm to 70 mm — so-called "normal" optics; shooting at such focal lengths provides a field of view closest to the human eye's field of vision;
  • from 70 to 135 mm — portrait optics (and some macro lenses for close-up shooting); in this range, volume is accurately conveyed when shooting people;
  • over 135 mm — long-range optics (telephoto lenses); large focal lengths are useful for shooting skittish wildlife, distant objects, sports events, etc.

This is how photos will look when shooting from one point at different focal lengths.
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2. Shutter Speed

The basis of photography is light, which passes through the lens and is captured on the camera sensor. Shutter speed determines the duration of light exposure on the image sensor. Shutter speed is also called the exposure time of the shot — it refers to the time interval during which the camera takes a picture.

Shutter speed is measured in seconds and fractions of a second. Short shutter speeds like 1/500 s or 1/4000 s are used for shooting moving objects in the frame, long ones (1/2 s, 30 s) — for capturing stationary objects and shooting in low light conditions. Note that fractional shutter speed values in the camera menu and on control dials are usually recorded without the fraction numerator (1/100 s is simply indicated as 100), and if the shutter speed is measured in whole seconds, it is denoted by a " (2 s is recorded as 2").

Shutter speed affects the amount of light reaching the sensor and the "freezing" of movements in the frame. On a bright sunny day outside, the image sensor receives enough light for proper exposure in just fractions of a second. But in low ambient light, the shutter speed needs to be extended, otherwise, the frame will be underexposed (dark). As for moving objects — the faster they move in the frame, the shorter the shutter speed needed, otherwise, there is a high risk of getting a blurred image. The entire shot can also be blurred due to camera shake in the photographer's hands.

The right photo shows the consequences of camera shake — blurring of the entire image when shooting handheld with a long shutter speed.

Therefore, there is a formula for calculating safe shutter speed depending on the focal length of the optics:

T = 1 / (f * K),

where f is the focal length, and K is the camera's crop factor.

For a conditional lens with a focal length of 50 mm paired with a full-frame camera, the safe shutter speed will be 1/50 s, and for the same lens on an APS-C crop — 1/75 s (1 / (50*1.5)).

Partly, optical image stabilization systems in lenses and sensor stabilization in cameras act as insurance against camera shake. With these, the safe shutter speed can be confidently extended by a couple of stops without the risk of image blur.

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3. Aperture, Brightness, and Depth of Field (DOF)

Aperture is an adjustable opening in the lens that controls the amount of light reaching the sensor. Typically, the aperture is a rotating disk consisting of several metal blades. This concept is synonymous with brightness — the degree of aperture opening inside the lens directly affects the brightness value, which is recorded as f/2.0, F2.0, or F1:2. The smaller the relative aperture value, the more open it is (i.e., f/1.8 is much "brighter" than f/5.6). This is detailed in a separate material "What is Lens Brightness and What Does It Affect".

If you look into the lens on the camera, different relative aperture openings are visible to the naked eye.

The degree of aperture opening directly affects the available range of shutter speeds and the depth of field of the imaged space (DOF). The more open its opening, the shorter the shutter speeds can be set, which is extremely important when shooting dynamic scenes and in low light conditions. As for depth of field, it decreases with increased brightness. Shooting with a shallow DOF at brightness values like f/1.4 or f/1.8 visually separates the foreground object from the background, which is indispensable in portrait photography, product shooting, and similar situations. Depth of field can be increased by closing the aperture (to f/4, f/5.6, and more).

When shooting with a fully open aperture, we get a shallow depth of field (example on the left),
while with a closed aperture, the entire shot will be sharp (right side of the frame).

Among fixed focal length lenses, bright models are considered models with a maximum aperture of f/2 and less. In the category of zoom lenses, these are models with a brightness of f/2.8.

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4. Sensitivity (ISO)

ISO units were used to measure the sensitivity of photographic film to light. This parameter has migrated to digital cameras. In general terms, it is the level of sensitivity of the camera sensor to light. For any image sensor, the working ISO range is specified (for example, from 100 to 25600 units). In many models, ISO can be extended both downwards and upwards by software means, but in practice, this is fraught with the appearance of artifacts in the images.

As we have already found out above, the amount of light reaching the sensor is determined by shutter speed and aperture. Depending on their values, the light is amplified to obtain a correctly exposed image. The degree of this amplification is digitally expressed by ISO sensitivity. The rule here is simple — the lower the ISO value, the higher the quality of the image. Increasing sensitivity leads to the appearance of noise artifacts in the photo — a set of pixels of random brightness and color.

The higher the ISO, the more noise artifacts will appear in the photo
(this is clearly visible when zoomed in).

In sunny weather, it is best to set the minimum sensitivity values: from 50 to 100 ISO units. On a cloudy day, you can raise the ISO to 200 – 400 units, indoors, you often have to set the sensitivity at the level of 800 to 3200 units. In the vast majority, these are the upper values for obtaining noise-free images, but in top full-frame cameras, ISO can be "raised" even more.

When shooting with a tripod or with a flash, make it a rule to set the minimum ISO.

Important point. Correctly selected proportions of shutter speed, aperture, and ISO are called exposure. In simple terms, it is such a combination of the above parameters that the photo is neither dark nor overexposed — just as needed. In manual shooting mode, you should first set the ISO, then open the required aperture opening, and finally adjust the shutter speed. A little practice — and the result will come.
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5. White Balance

White balance affects the accuracy of color reproduction. Why is the parameter called that? The fact is that the true colors of objects appear when they are illuminated by white light. If the light source is not white, the colors in the photo begin to distort. White balance adjustment eliminates extraneous shades and ensures realistic color reproduction.

In the vast majority of situations, the camera's automation successfully handles the choice of the correct white balance. But sometimes it does not work or makes mistakes. Then you can use standard presets: sun, cloudy weather, daylight lamp, or incandescent lamp, etc. In advanced cameras, you can even show the camera the light source and set the white balance by it or by a white sheet of paper, but only professional photographers will bother with this.

The left frame was taken with the "Daylight" white balance, the right one — with the "Fluorescent lamp" preset.

Note that WB adjustment is a fixable thing. To do this, it is enough to shoot in RAW format. The correct balance is set in any converter with a couple of mouse clicks. But to avoid wasting time on post-production, it is best to take care of setting the white balance directly during shooting.

6. RAW and JPEG

Since we touched on the RAW format, it is worth briefly talking about it. RAW is a "raw" format, essentially a digital negative. It contains the maximum information from the camera's image sensor. Shot materials in RAW must be post-processed in specialized editors (Photoshop, Lightroom, etc.). The main advantage of the format is that RAW provides extensive possibilities for correcting the source files, whether it is brightening or darkening the photo, color correction, sharpness, and detail.

In the Camera Raw environment, you can flexibly "tweak" the image with various sliders.
The maximum data can be extracted from RAW format photos,
but if desired, you can try to correct JPEG files as well.

After processing, RAW files are compressed into familiar image formats, one of which is the popular JPEG. If you do not intend to bother with painstaking post-processing of photos, you can shoot directly in JPEG format. This is the product of in-camera processing of frames. It weighs much less and saves space on the flash drive, and during continuous shooting in JPEG, the camera buffer holds many more frames. Photos in this format can be immediately published on social networks, but in terms of processing capabilities, they are significantly inferior to the "raw" RAW. Correcting photos in JPEG with deliberately incorrect camera settings is almost useless, whereas in RAW most problems are solvable without loss of image quality.

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