Zoom digital what. Difference between optical and digital zoom on digital cameras
2 years ago
When buying a camera or camcorder, it is always recommended to pay attention to the possibility of getting closer to the subject of the image. This is the so-called zoom, or zoom. For those who are going to take pictures for a family album with a camera in their hands, maybe the zoom is not so important. However, for the professional photographer, zoom is not something to be neglected.
In this case, of course, it must be said right away that the zoom can be both optical and digital. And this is not the same thing as someone ignorant might think.
Optical zoom can be obtained through optics. This approximation assumes the use of an eyepiece. That is, the viewing angle is reduced, but the resulting image is transferred to the same canvas. This approximation allows for some distortions, but objectively speaking, they are minimal. That is, some linear distortions of objects are possible, but you will not immediately notice them with an ordinary eye.
Digital zoom is different. Here we get the result, take some fragment from it, that is, crop it, and then stretch this fragment. Alas, our camera cannot clarify any details. The microfragments have already been filled. As a result, these pixels have to be increased, that is, to transfer the color of one to several others, neighboring. Due to such squares in the image, the image resolution decreases as a result.
If someone says that digital zoom- this is bad, then you can argue with him. Still, you can use digital zoom and still have a high-quality image. In particular, in multi-pixel equipment, which has a certain amount of pixels. However, there is still a limit to the use of digital zoom.
But the optical zoom is still better. Optical zoom is an optical system. It is she who helps to change the focal length of the lens. This is why distant objects are seen closer. Optical zoom brings them closer with virtually no loss in quality. The distance between pixels does not decrease as you zoom in. Experts believe this is a significant advantage.
Especially the optical zoom can be useful for reportage shooting. It is also useful for tourists who want to take photographs of any sights, landscapes, and so on. After all, there are times when there is no need to approach the object of interest to you closer. It is enough to stay in place, and you just need to slightly tweak the zoom value.
How more value the optical zoom in a digital camera is better. By the way, today you can often see cameras with more than 20x optical zoom.
Many digital cameras have both digital and optical zoom. Usually they are presented in the form of two independent functionalities, or integrated into a single image enlargement function. For first-time buyers of a camera, these two features can be a little embarrassing until they know which option is best for them.
Optical zoom works the same as standard zoom. When you change the focal length of the lens (by rotating or shifting the lens barrel), it visually brings the subject closer to you. The advantage of optical zoom is that as you zoom in on your subject, you also maintain image quality. Why? Because you are magnifying your image before you take the picture.
Digital zoom works differently. It makes the image large after you capture it in the lens, and crops the image as soon as you press the camera shutter. But after cropping, the remaining pixels of the camera sensor are located farther from each other, since the physical dimensions of the image do not change. Therefore, the resulting image looks large, and its quality is significantly reduced, especially if you need to print large format images.
From a technological point of view, you can solve the problem of enlarging your subject with digital zoom, but the image will not be as sharp as when using optical zoom. Generally speaking, it is best (if possible) to turn off the digital zoom on your camera, especially if you plan on printing your photographs on paper. This will help prevent automatic zooming when the subject is too close to the subject, as digital zoom is often an expanding feature of the optical zoom.
At the same time, there are several ways with which you can bring your subject closer and maintain the quality of its image - move closer to your subject. Often, just one or two steps will do the trick. If this is not possible, then set the camera to the highest possible image quality. This will keep the image sharp enough even after being “cropped” by the digital zoom.
Digital zoom is making its way too. It can be used if your images are for the web only. Online images can be much lower quality - 72 ppi (72 pixels per inch) and are still acceptable for web gallery placement or as part of a blog post. If your goal is to print photographic images at 300 dpi (300 dpi) quality, then you need to purchase a camera that has a large optical zoom and the ability to disable digital zoom. Your prints will get much better quality and you will be happy.
Articles and Life Hacks
Our material is for those who want to understand what the digital zoom actually is, which is available in your smartphone, according to the characteristics listed on the seller's website.
In fact, there is absolutely nothing complicated in it: it is just a software scaling of the image received from the camera sensor before saving it to a photo into a file.
What else is zoom
Why digital? Because besides it, the zoom is also optical. Moreover, if it comes about cameras, it is much more common in them.The camera lens is large enough to allow designers to anticipate a change in focal length. It is this parameter that determines how "close" or "far" in relation to the photographer the subject will appear in the picture.
The focal length range in specialized cameras is from 10 to several hundred millimeters. Moreover, for them, the developers provide for interchangeable optics, both short-focus (wide-angle) and long-focus (telescopic).
The design of the smartphone camera does not allow anything like that. Therefore, their creators have to get out, compensating for the weakness through the use of software.
What are the disadvantages of digital zoom
First of all, it degrades the quality of the resulting images. The amount of information received from the camera sensor is fixed: the smartphone cannot change either its resolution or the characteristics of the lens system.Therefore, in order to get an image of a larger scale with the same image size, the image has to be "stretched" programmatically. At the same time, the clarity of details deteriorates, and digital noise appears.
How to deal with it
There are several options to combat the impact of digital zoom on smartphone image quality, so you can choose the most suitable:
- Purchase expensive model with optical zoom.
- Choose a device with a high-quality dual-module camera.
- Save the picture in RAW format in order to edit it on a PC.
Smartphones with good dual-module cameras can't be called cheap either. However, their device allows you to get better photos due to the difference in the focal length of each of the modules.
One of them can be wide-angle, and the other one is telephoto. By combining the information received from the two sensors, the camera application is capable of digital zooming much more correctly.
The latter option, oddly enough, is also found only in top-end, in extreme cases - sub-flagship models.
Unlike saving images in JPEG format, which leads to serious loss of quality when they are further edited, RAW format saves much more data and allows you to get a much higher quality image.
Unfortunately, such files take up much more space than JPEGs.
The conclusion from the above is unambiguous: cheap phones are not designed for high-quality photography. Those who do not want to purchase a separate camera, but want to get impressive photos, need to choose a model from the top segment.
Even digital zoom will be much better in it than in a budget gadget.
Pixel - (from the words picture element - an element of an image) is an elementary colored point, the combination of which forms an image.The sensor is made up of megapixels, or millions of pixels. The more of them, the higher the resolution of the camera. Modern cameras have matrices with a resolution of 4,6,8 or more megapixels. For example, for printing photos in 10x15 and 15x20 formats, a resolution of 4 or 6 megapixels is sufficient.
What is the matrix made of?
The matrix consists of many light-sensitive cells - pixels.
Each cell, when light hits it, generates an electrical signal proportional to the intensity of the light flux. Since only the brightness of the light is used, the picture is black and white. To make it colored, the cells are covered with colored filters. In most matrices, each pixel is covered with a red, blue or green filter, in accordance with the RGB (red-green-blue) color scheme. Only three colors are used, since these are the main colors and all the others are obtained by mixing them. The filter lets only rays of its own color into the cell.
The image obtained on the matrix consists only of red, blue and green pixels - this is the form in which RAW files are recorded (unprocessed format). To record JPEG and TIFF files, the camera analyzes the color values of adjacent cells and calculates the color of the pixels.
Usually cameras are 2, 4, 8, 16 microseconds. The aspect ratio of compact digital cameras is made with an aspect ratio of 4: 3, rarely 16: 9. In mirrors digital cameras use matrices with an aspect ratio of 3: 2. In the camera menu, the user can select the aspect ratio from the options available in the camera, for example, 16: 9, 3: 2, 4: 3, 1: 1, 4: 5. In this case, the frame will be cropped in height or width.
What is zoom? What types of zoom are there?
Zoom is the ability of a camera lens to magnify objects of photography several times. The number of times the camera can "zoom in" on the subject is called the zoom factor.If we are talking about a digital camera, then it is necessary to separate two terms: optical zoom and digital zoom.
Optical zoom- this is the image that the camera allows you to take with the help of optical lenses. In other words, it is a smooth transition from general plan to large without loss of quality (!). Optical zoom 3X - 4X means that the camera, by changing the focal length of the lenses, can "bring you closer" to the subject of photography 4 times.
Digital zoom just enlarges the fragment, as a graphics editor would do. This does not add new pixels, but simply increases the size of the existing ones. Consequently, image quality is lost. The picture will not reveal any new details. The same result can be obtained if this image is enlarged on a computer using a graphic editor.
An example of fragments of a landscape obtained using optical and digital zoom.
Result:
Exposition
Exposure is a quantitative measure of the light energy incident on a photosensitive element, the result of the interaction of aperture and shutter speed parameters.The term is often used - exposure, during which shooting takes place. If the shutter speed and aperture values are set correctly, the frames will look natural and correspond to reality. The quality of the picture largely depends on the exposure - insufficient exposure (called underexposure by photographers) leads to poor development of details in the shadows, overexposure (overexposure) - to poor study of bright areas.
Excerpt
Exposure - the time of exposure to light on a sensitive material - a matrix (or film).This is the time during which the shutter of the camera remains open and light acts on the sensor. Shutter speed is measured in seconds. The shutter speed is also selected depending on the creative tasks of the photographer:
For stationary objects, the use of long exposures is justified, especially for night photography, when the maximum open aperture is not enough for a normal exposure.
It should be noted that with long exposures:
- moving objects are blurry;
- the camera will react to the slightest hand movements and displacement of the device, in these cases a tripod or fixed support for the camera is required.
Diaphragm
An aperture is a device in a lens that allows you to change the amount of light that hits the film.The diaphragm changes the diameter of the "hole", thereby adjusting the amount of light that illuminates the matrix. The diameter of the "hole" is characterized by the diaphragm number (in common use - the diaphragm).
For example, for portraits, choose a small f-number, 3.5. This allows you to sharpen the figure of the person and blur the background. For landscape photography, you need to choose a larger aperture - 4 or 5.6 or even 8 so that all objects in the frame are sharp.
Depth of field
Depth of field in imaged space is the distance between two planes in space, within which objects in the image are perceived as clear and not blurry.By choosing the aperture, you can change the depth of field. Thus, various artistic effects can be created.
Depth of field control is used to accentuate a subject surrounded by other, secondary subjects. A traditional example is portrait, when you need to get a sharp face and a blurred background. The shallow depth of field makes this effect easy to achieve. As reverse example you can bring landscape photography, where for a sharp transfer of details, both in the foreground and in the background, a maximum depth of field is needed.
An example of obtaining a different depth of field:
It should be noted that:
- The larger the f-number (the smaller the aperture diameter), the greater the depth of field.
- The further from the lens the subject is, the deeper the depth of field.
- The shorter the focal length of the lens (the larger the angle of view of the lens), the greater the depth of field.
Focal length of the lens
Focal length is the distance between the film and the optical center of the lens at infinity. According to the ratio of the focal length and the diagonal of the frame, the lenses are divided into normal, short-focus, long-focus, as well as lenses with a variable focal length.
The short-focus lenses provide large viewing angles. Lenses with long focal lengths provide telephoto lenses with small angles of view, but allow you to shoot distant objects with greater magnification than conventional lenses.
What is ISO?
ISO is a numeric parameter that controls sensitivity to light. The higher it is, the brighter and richer your photos will be.That is, the higher the ISO value, the less light and time it takes for the sensor to capture a frame without a flash. But (!) With an increase in the sensitivity of the matrix, the so-called noise (unpleasant graininess) increases. As the shutter speed increases, the picture may appear out of focus (starting at 1/60 sec).
IN this example the photographer set different ISOs, all other things being equal.
| ISO = 50 | ISO = 400 |
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What is DPI and why 300 DPI?
There are two different concepts about image resolution.
1. The absolute resolution of the photo is the size of the image in pixels. If the camera has an 8 MegaPixel matrix, which generates an image with a pixel size of 3264 * 2448, then it will be written to the file with the same size 3264 * 2448. It is important to understand that if, after editing in any program, the image remains the same size, then its resolution will not change.
2. DPI (abbreviation for dots per inch) is a value that determines the number of dots (bitmap elements) per unit area (or unit of length). This resolution determines how detailed your image will be when printed. So the real resolution in DPI is obtained only when printing, based on the paper size and the size of the photo in dots. As long as the print settings are unknown and the photo is on your computer, such a photo has no concept of DPI. It will only make sense when printed.
Let's look at some examples.
A 6 MegaPixel camera will give you a 3000 by 2000 pixel photo. Let's try to print a 3000 by 2000 pixel photo on a computer with a resolution of 300 DPI. Let's consider that 1 inch is 2.54 cm. So at 300 DPI there will be 300 pixels in each inch. Dividing the length 3000 by 300 gives the number of inches = 10. Translated into cm, we get a length of 25.4 cm. We will do the same with the width. (2000/300) * 2.54 = 16.9 cm. Our photo (3000 x 2000 pixels) when printed at 300 DPI will have a print size of 25.4 cm by 16.9 cm.
Let's take the opposite situation. You want to print a photograph of 4x6 inches (10x15 cm).
A photo with a size of 600x900 pixels (0.5 megapixel), will be printed with a resolution of 150dpi
A photo with a size of 1200x1800 pixels (2 megapixels), will be printed with a resolution of 300dpi
Photo with size 2400x3600 pixels (8 megapixel), will be printed with a resolution of 600dpi
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Where does the DPI entry in the file properties come from? The file properties record the recommended viewing resolution on the monitor. You can change this value to any other integer. In this case, no changes in the quality of the photo stored on your computer will occur. If you are asked for images in exactly 300 DPI, feel free to change this value in the file! This can be done in Photoshop and other editors.
What does the histogram stand for?
A histogram is a graph by which you can judge the brightness of a photo. In other words, this is a diagram of the distribution of the brightness of the image - from the darkest area to the brightest. The scale at the bottom is divided in proportion to the brightness levels: on the left it corresponds to the darkest areas of the image, and on the right - the lightest, with shades of gray between them. The number of pixels is plotted along the vertical scale. The histogram allows you to more accurately set the exposure.What format to shoot?
Some cameras allow you to select the format of your photos.RAW- internal digital camera format for image recording. Files of this format contain raw (or minimally processed) data, which avoids information loss.
Tiff(Tagget Image File Format) is an image format that saves images without losing quality. This format allows you to save data without compression, or it can use LZW compression, which ensures that the original data is completely preserved.
Zoom in cameras is an essential characteristic. This is not even a characteristic of the camera itself, but rather a parameter of the lens. It depends on the value of the FR (focal length). The focal length itself is expressed in millimeters, it determines the distance from the focal point (matrix) to the middle of the lens. If you take any lens and carefully consider what is written on it, you can find 2 values, for example: 5.8-24 mm. This pair of numbers denotes the focal length. In this case, the focal length at the short end will be 5.8 mm, at the long end - 24 mm. If these two values are divided by each other, then we get the zoom value. Here 24 divided by 5.8 equals 4.
Zoom(aka zoom) is used for zoom lenses, so these two concepts are closely related to each other. Basically, zoom determines how many times the camera can magnify the subject. This is exactly what most sales assistants tell the buyer. This is partly true, but you need to understand that the zoom value is far from the most important selection criterion, and it does not affect the quality of the resulting images in any way.
Optical zoom
Optical zoom is most commonly found on SLR or mirrorless cameras that use interchangeable lenses. It is a characteristic of the camera optics itself. Removing or approaching an object is carried out "by hand" due to the shift of the lenses in the lens, while other parameters of the camera do not change. Consequently, the optical zoom does not affect the quality of the captured images, which even allows you to take photos with close objects. good quality(sorry for the tautology).
Digital zoom
Digital zoom - this is exactly what is indicated in the characteristics of the camera this parameter... The attitude to such a "zoom" is not always good, and this is quite fair. The digital zoom works like this: the camera processor cuts out the desired piece from the photo and stretches it to the full size of the matrix. In this case, there is no real magnification of the object. Rather, it is, but such an "increase" can be obtained in the paint program, simply by increasing the image by a certain percentage. The resolution of the cut piece will suffer from this, and the quality will also suffer.
Therefore, when it comes to zoom, it is more appropriate to talk about optical. It is often better to turn off the digital zoom in the camera settings.
However, sometimes there is no other choice, so you have to resort to using digital zoom to enlarge the desired subject.
Ultrasights
Now there are digital cameras with so-called ultrazoom or superzoom, if you like. The optical zoom parameter in them can reach 50x and even more.
The simplest example - Here the zoom reaches 60x. Easy to determine: focal length: 4.3-258mm (hence the value 60). There is such a device on this moment about $ 400.
From myself: I personally have had such a camera for a long time. I had to take it back, because I smeared the pictures a lot. In inept hands, it is quite difficult for them to get high-quality detailed images, so I do not recommend it to beginners. The zoom is really impressive here!
Zoom, aperture and more
Focal length and, accordingly, zoom are closely related to factors such as aperture. The aperture value determines how much light will pass through the lens and hit the sensor. The more you zoom, the more lenses are used in the lens and the less light will hit the matrix. Consequently, quality will be lost.
In all lenses, next to the FR, the aperture parameter is indicated for each of the distances. If the FR parameter for two different cameras is the same, then it is better to choose a model where the aperture parameter will be higher. The quality of pictures on such a device will be better. If you take a compact camera with a zoom value of more than 4x, then here the aperture value will not be high and the quality of the photo will hardly please.
You can also often find cameras with the same zoom value, but with different focal lengths. For example, both devices have 3x zoom. In this case, the FR in one is equal to 70-210 mm, in the other - 18-55 mm. In this case, one device is used for landscape photography, the other for portraits. Although the zoom value is the same here, their purpose is completely different. Therefore, when choosing a camera, you should not be guided by the zoom parameter as a selection criterion.
