Comparison Apple iPhone 8 Plus 64 GB vs Apple iPhone X 64 GB

Characteristics of the main (and most often the only) display installed in the device.

In addition to the basic properties - such as size, resolution (according to it, screens are conventionally divided into HD, Full HD, 2K and more), sensor type (most often IPS, OLED, AMOLED, Super AMOLED, Dynamic AMOLED,), this list can more specific features. Among them are the shape of the surface ( flat or curved), the presence and version of the Gorilla Glass coating (including the top v6 and Victus), HDR support and the refresh rate (a frequency on top 60 Hz is considered high, namely 90 Hz, 120 Hz and 144 Hz) . Here is a more detailed description of the characteristics relevant to modern displays:

- Size. Traditionally, the screen size is indicated in inches. A larger display is more convenient to use: more information is placed on i...t, and the image itself is better readable. The downside of increasing the size is an increase in the dimensions of the device. Today, smartphones with screens of 5" or less are considered small. 5.6 - 6" and up to 6.5" is already a medium format. Also, many modern models have a size of 6.5". Classic phones without touch screens do not need a large size - in them it usually does not exceed 3".

- Permission. Screen resolution is specified based on its vertical and horizontal dimensions in dots (pixels). The larger these dimensions (with the same size) - the more detailed and smoothed the picture looks and the less individual pixels are visible on it. On the other hand, increasing the resolution increases both the cost of the display itself and the requirements for the phone's hardware. It is also worth noting that the same resolution on screens of different sizes looks different; so when evaluating detail, it is worth considering not only this parameter, but also the PPI number (see below).

— PPI. The density of dots (pixels) on the screen of the device. It is indicated by the number of dots per " (points per ") - the number of pixels for each horizontal or vertical segment of 1 ". This indicator depends both on the size and resolution, but in the end it is the PPI number that determines how smooth and detailed the image on the display is. For comparison, we note that at a distance of about 25 - 30 cm from the eyes, a density of 300 PPI or more makes individual pixels almost invisible to a person with normal vision, the picture is perceived as a complete one; at greater distances, a similar effect is noticeable at a lower point density.

— Matrix type. The technology by which the screen sensor is made. This parameter is indicated only for relatively advanced displays that are superior in performance to the simplest LCD screens of push-button phones. The most widespread in our time are the following types of matrices:

• IPS. The most popular technology for the screens of modern smartphones. It provides a very decent image quality, viewing angles and response speed, although it is somewhat inferior in these parameters to many more advanced options (see below). On the other hand, IPS also has important advantages: durability, uniform wear, and also a rather low cost. Thanks to this, such screens can be found in all categories of smartphones - from low-cost to top-end.
• AMOLED. Organic light-emitting diode (OLED) sensor technology developed by Samsung. One of the key differences between such matrices and more traditional displays is that they do not require external illumination: each pixel is its own light source. Because of this, the power consumption of such a screen depends on the characteristics of the displayed image, but in general it turns out to be quite low. In addition, AMOLED matrices are distinguished by wide viewing angles, excellent brightness and contrast ratios, high color reproduction quality and fast response time. Due to this, such screens continue to be used in modern smartphones, despite the emergence of more advanced technologies; they can be found even in top-end models. The main disadvantage of this technology is the relatively high cost and uneven wear of the pixels: dots that work longer and more often at high brightness burn out faster. However, usually this effect becomes noticeable only after several years of intensive use - a period comparable to the operational resource of the smartphone itself.
• AMOLED (LTPO). An advanced version of AMOLED panels with the ability to dynamically adjust the refresh rate depending on the tasks performed. The abbreviation LTPO stands for Low Temperature Polycrystalline Oxide. Behind this term is a combination of traditional LTPS technology and a thin layer of TFT oxide film with the addition of hybrid-oxide polycrystalline silicon to drive the sweep switching circuits. AMOLED panels (LTPO) reduce the energy consumption of the gadget by an order of magnitude. So, when performing active actions, the device screen uses the maximum or high refresh rate, and while viewing pictures or reading text, the display reduces the rate to a minimum.
• Super AMOLED. An improved version of the AMOLED technology described on top One of the key improvements is that in Super AMOLED screens there is no air gap between the touch layer and the display located under it. This made it possible to further increase the brightness and image quality, increase the speed and reliability of the sensor response and at the same time reduce power consumption. The disadvantages of such matrices are the same as the original AMOLED. In general, they are quite widespread; most smartphones with similar screens belong to the middle and top categories, but there are also low-cost models.
• OLED. Various types of matrices based on the use of organic light emitting diodes; in fact - analogues of AMOLED and Super AMOLED, produced not by Samsung, but by other companies. The specific features of such screens may be different, but for the most part they are, on the one hand, more expensive than popular IPS, on the other hand, they provide higher image quality (including brightness, contrast, viewing angles and color fidelity), and also consume less energy and have small thickness. The main disadvantages of OLED screens are the high price (which, however, is constantly decreasing as the technology develops and improves), as well as the susceptibility of organic pixels to burn-in when broadcasting static images for a long time or images with static elements (notification panel, on-screen buttons, etc.). ).
• OLED (polymer). Organic Light-Emitting Diode (OLED) screens, which do not use glass as a base, but a transparent polymer material. We emphasize that we are talking about the basis of the sensor; from on top it is covered with the same glass as in other types of screens. However, this design offers a number of advantages over traditional "glass" matrices: it provides additional impact resistance and is great for creating curved displays. On the other hand, in terms of optical properties, plastic still falls short of glass; so screens of this type are often inferior in image quality to their “peers” made using traditional OLED technology, and with a similar picture quality, they are noticeably more expensive.
• OLED (LTPO). OLED-matrices with adaptive refresh rate, which can be changed in a wide range based on the tasks performed. In games, screens with LTPO technology automatically raise the refresh rate to the maximum values, while viewing static images, they reduce it to a minimum (from 1 Hz). At the heart of the technology is a traditional LTPS substrate with a thin TFT oxide film on top of the TFT base. The ability to control the flow of electrons provides dynamic control over the refresh rate. The competitive advantage of OLED (LTPO) is reduced power consumption.

In addition, screens in modern smartphones can be made using the following technologies:

• pls. A variation of IPS technology created by Samsung. In some respects - in particular, brightness, contrast and viewing angles - it surpasses the original, while it is cheaper to manufacture and allows you to create flexible displays. However, for a number of reasons, it is not particularly popular.
• Super AMOLED Plus. A further development of the Super AMOLED technology described on top. Allows you to create even brighter, more contrasting and at the same time thin and energy-efficient screens. However, most often such screens in our time are simply referred to as "Super AMOLED", without the "Plus" prefix.
• Dynamic AMOLED. Another AMOLED improvement introduced in 2019. The main features of such matrices are increased brightness without a significant increase in power consumption, as well as 100% coverage of the DCI-P3 color space and compatibility with HDR10 +; the last two points, in particular, make it possible to reproduce modern high-low-cost cinema on such screens with the highest quality. The main disadvantage of Dynamic AMOLED is traditional - the high price; so such matrices are found mainly in top models.
• Super Clear TFT. A joint development by Samsung and Sony, which appeared as a forced alternative to Super AMOLED matrices (the demand for them at one time significantly exceeded production capabilities). True, the image quality of Super Clear TFT is somewhat lower - but in production such matrices are noticeably simpler and cheaper, but in terms of performance they still surpass most IPS screens. However, in our time, this technology is rare, giving way to AMOLED in different versions.
• super LCD. Another alternative to various kinds of AMOLED technology; used mainly in HTC smartphones. Similar to Super AMOLED, such screens do not have an extra air gap, which has a positive effect on both image quality and the clarity of sensor responses. A notable advantage of the Super LCD is its good power efficiency, especially when displaying bright whites; but in terms of overall color saturation (including black), this technology is noticeably inferior to AMOLED.
• LTPS. An advanced type of TFT matrices, created on the basis of the so-called. low temperature polycrystalline silicon. It allows you to easily create screens with a very high pixel density (more than 500 PPI - see on top), achieving high resolutions even with a small size. In addition, part of the control electronics can be built directly into the sensor, reducing the overall thickness of the display. The main disadvantage of LTPS is the relatively high cost, but nowadays such screens can be found even in low-cost smartphones.
• S-PureLED. A technology developed by Sharp and used primarily in its smartphones. Actually, the technology of the matrices themselves in this case is called S-CG Silicon TFT, and S-PureLED is the name of a special layer used to increase transparency. S-CG Silicon TFT is positioned by the creators as a modification of the LTPS technology described on top, which allows to further increase the resolution of the display and at the same time build more control electronics into it (up to a whole “processor on glass”) without increasing the thickness. Of course, these screens are not cheap.
• e-ink. Matrices based on the so-called "electronic ink" - a technology common primarily in electronic books. The main feature of such a screen is that during its operation, energy is spent only on changing the image; a still picture does not require power and can remain on the display even in the absence of power. In addition, by default, E-Ink matrices do not glow on their own, but reflect outside light - so their own backlight is not necessary for them (although it can be provided for work at dusk and darkness). All this provides a solid energy savings; and for some users, such screens are purely subjectively more comfortable and less tiring than traditional matrices. On the other hand, E-Ink technology also has serious drawbacks - first of all, a long response time, as well as the complexity and high cost of color displays, combined with poor color reproduction quality on them. In light of this, in smartphones, such matrices are a very rare and exotic option.

— Sweep frequency. The maximum display refresh rate, in other words, the highest frame rate that it can effectively reproduce. The higher this figure, the smoother and smoother the image is, the less noticeable the “slideshow effect” and blurring of objects when moving on the screen. At the same time, it should be borne in mind that the refresh rate of 60 Hz, supported by almost any modern smartphone, is quite sufficient for most tasks; even high-definition videos hardly make use of high frame rates these days. Therefore, the scanning frequency in our catalog is specially specified mainly for screens capable of delivering more than 60 Hz (in some models - up to 240 Hz). Such a high frequency can be useful in games and some other tasks, it also improves the overall experience of the OS interface and applications - moving elements in such interfaces move as smoothly as possible and without blurring.

HDR. A technology that allows you to expand the dynamic range of the screen. In this case, the range of brightness is implied - simply put, the presence of HDR allows the screen to display brighter whites and darker blacks than on displays without support for this technology. In practice, this gives a noticeable improvement in image quality: the saturation and reliability of the transmission of various colors improves, and the details in very light or very dark areas of the frame do not “sink” in white or black. However, all these advantages become noticeable only on the condition that the content being played is originally recorded in HDR. Nowadays, several varieties of this technology are used, here are their features:

• HDR10. Historically the first of the consumer HDR formats, it is extremely popular today: in particular, it is supported by almost all streaming services with HDR content and is standardly used for such content on Blu-ray discs. Provides a color depth of 10 bits (more than a billion shades). At the same time, HDR10+ format content (see below) can also be played on devices with this technology, except that its quality will be limited by the capabilities of the original HDR10.
• HDR10+. An improved version of HDR10. With the same color depth (10 bits), it uses the so-called dynamic metadata, which allows transmitting information about the color depth not only for groups of several frames, but also for individual frames. This results in an additional improvement in color reproduction.
• Dolby vision. An advanced standard used particularly in professional cinematography. It allows you to achieve a color depth of 12 bits (almost 69 billion shades), uses the dynamic metadata mentioned on top, and also makes it possible to transmit two image options at once in one video stream - HDR and normal (SDR). At the same time, Dolby Vision is based on the same technology as HDR10, so in modern electronics this format is often combined with HDR10 or HDR10 +.

- DC Dimming support. Literally from English, Direct Current Dimming is translated as direct current dimming. This technology is designed to minimize flicker in OLED and AMOLED screens, which, in turn, reduces the load on the user's visual apparatus and protects eyesight. The “flicker-free” effect is achieved by directly controlling the brightness of the backlight LEDs by changing the voltage applied to them. Due to this, a decrease in the intensity of the glow of the screen is ensured.

- Curved screen. A screen that has curved edges to which the displayed image extends. In other words, in this case, not only glass is curved, but also part of the active sensor. Displays where both edges are curved are sometimes referred to as "2.5D glass" as well; also there are devices where the screen is bent only on one side. In any case, this feature gives the smartphone an interesting appearance and improves the visibility of the image from some angles, but it significantly affects the cost and can create inconvenience when holding (especially without a case). So before buying a model with such equipment, ideally, you should hold the device in your hand and make sure that it is comfortable enough.

- Gorilla Glass. Special high-strength glass used as a display cover. It is characterized by endurance and resistance to scratches, many times superior to ordinary glass in these indicators. It is widely used in smartphones, where large screen sizes put forward increased requirements for coverage reliability. Modern phones may have different versions of this glass, here are the features of different options:

• Gorilla Glass v3. The oldest of the current versions is released in 2013; now found mainly among inexpensive or obsolete devices. However, this coating also has undoubted advantages: this is the first generation of Gorilla Glass, where the creators have made a noticeable emphasis on resistance to scratches from keys, coins and other objects that the phone can “collide” in a pocket or bag. In this respect, the v3 version remained unsurpassed until the release of Gorilla Glass Victus in 2020.
• Gorilla Glass v4. Version released in 2014. A key feature was that the development of this coating focused on impact resistance (whereas previous generations focused mainly on scratch resistance). As a result, the glass is twice as strong as in version 3, despite the fact that its thickness is only 0.4 mm. But here's the scratch resistance, compared with its predecessor, has decreased slightly.
• Gorilla Glass v5. A gorilla improvement released in 2016 to further improve impact resistance. According to the developers, the glass of the v5 version is 1.8 times stronger than its predecessor, remaining intact in 80% of drops from a height of 1.6 m "face down" on a rough surface (and guaranteed impact resistance is 1.2 m). Scratch resistance has also improved somewhat, but this material still falls short of v3 performance.
• Gorilla Glass v6. Version introduced in 2018. For this coating, a 2-fold increase in strength compared to its predecessors is claimed, as well as the ability to endure multiple drops on a hard surface (in tests, v6 glass successfully endured 15 drops from a height of 1 m). The maximum drop height (single) with guaranteed integrity is declared at 1.6 m. Scratch resistance has received practically no improvement.
• Gorilla Glass 7. Original name for Gorilla Glass Victus - see below.
• Gorilla Glass Victus. The "heir" of Gorilla Glass 6, released in the summer of 2020. In this coating, the creators paid attention not only to increasing the overall strength, but also to improving scratch resistance. According to the latter indicator, Victus surpasses even the v3 version, not to mention more sensitive materials (and compared to v6, scratch resistance is claimed to be twice as high). As for durability, it allows you to guarantee to endure single drops from a height of up to 2 m, as well as up to 20 consecutive drops from a height of 1 m.

The ratio of the screen area to the total front panel area of the phone. Simply put, this spec describes how much of the front panel is occupied by the screen; the rest is the bezels.

This indicator is given exclusively for smartphones with touch screens — it is for them that it is most relevant. The larger the percentage of the body is occupied by the screen, the thinner are the bezels, the neater the smartphone looks and the more convenient it is to work with it with one hand. As for specific numbers, the average values are 80 – 85 %, the higher values allow us to talk about a thin bezel, and more than 90 % — about a “bezel less” design.

Separately, we note that this parameter has nothing to do with the aspect ratio of the screen. The aspect ratio describes only the display itself — its proportions, the ratio between the larger and smaller side of the rectangle.

The test results are specified either by a younger model in a line or a particular model, made for a better understanding performance of phone models if you compare phones against these parameters. For example, the 128 GB model has test results, and the 256 GB model has no information on the network, and in both models you will see the same value that will give an understanding of the overall performance of the device. But if the editorial office has information for each model individually, then each model will have its test results filled out, and the model with bigger RAM will have bigger values.

The result shown by a device when undergoing a performance test (benchmark) in AnTuTu Benchmark.

AnTuTu Benchmark is a comprehensive test designed specifically for mobile devices, primarily smartphones and tablets. It evaluates the efficiency of the processor, memory, graphics, and input/output systems, providing a clear impression of the system's capabilities. The higher the performance, the more points are awarded. Smartphones that score over 900K points are considered high-performance according to the AnTuTu ranking.

Like any benchmark, this test does not provide absolute precision: the same device can show different results, usually with deviations within 5-7%. These deviations depend on various factors unrelated to the system itself, such as the device's load from third-party programs and the ambient temperature during testing. Therefore, significant differences between two models can only be noted when the gap in their scores exceeds this margin of error.

The result shown by a device when undergoing a performance test (benchmark) in Geekbench.

Geekbench is a specialized benchmark designed for processors. Since version 4.0, it also includes tests for graphics processors, and by the end of 2019, version 5 of the benchmark was released. Typically, the specifications for portable gadgets include data specifically for the CPU. During testing, Geekbench simulates workloads that occur during real-world tasks, evaluating both single-core performance and the efficiency of multi-core operations. This provides a solid overview of the processor's capabilities in everyday use. Additionally, Geekbench is cross-platform, allowing for comparisons between the CPUs of different devices (smartphones, tablets, laptops, PCs). In reference materials, only the multi-core test results for the processor are usually provided.

The result shown by the device when passing the 3DMark Gamer's Benchmark performance test.

3DMark is a series of benchmarks originally designed to test the graphics performance of a device; later, these tests were supplemented by checking the capabilities of the processor. Testing is carried out primarily in terms of performance in games (in fact, the benchmark itself is described as “a game without the ability to influence the process”), however, given that modern games can have very high requirements, 3DMark is a fairly visual tool for assessing the overall performance of the system . And since the latest versions of the test are made cross-platform, it also makes it possible to compare devices under different operating systems and even different classes (for example, smartphones with tablets). The more points this or that model received on this test, the more performant it is.

It is worth noting that the results of any benchmark are usually quite approximate, because. they depend on many factors that are not directly related to the system — from the load of the device with third-party programs and ending with the air temperature during testing. The error due to these factors is usually about 5 – 7 %; therefore, it is possible to speak of a significant difference between the two models only if the difference in their indicators goes beyond those 5 – 7%.

The result shown by the phone in the 3DMark Sling Shot Extreme (OpenGL ES 3.1 / METAL) test.

3DMark is a series of benchmarks originally designed to test the GPU performance of a device; later, these tests were supplemented by checking the capabilities of the CPU and RAM in general. Specifically, Sling Shot Extreme is one of the latest versions of 3DMark, released in 2016 for testing high performance devices and gaming smartphones, for which earlier tests are no longer enough. One of the key features of the test is support of resolutions up to 2560x1440 (for predecessors, the maximum resolution did not exceed 1920x1080, or even 1280x720). In addition, as the name suggests, the test supports the OpenGL ES 3.1 (for Android) and Metal API (for iOS) specifications used in modern mobile video chips; and since mid-2019, support of the 64-bit CPU architecture has also been added to it. Thus, 3DMark Sling Shot Extreme allows you to reliably evaluate even the most performant and advanced modern smartphones. At the same time, the assessment is traditionally indicated in points: the more points, the better the result.

The results of any benchmark are usually quite approximate, because they depend on many factors not directly related to the system. The error due to these factors is usually about 5 – 7%; therefore, it is possible to speak of a significant difference between the two models only if the difference in their indicators goes beyond those 5 – 7%.

Specifications of the main lens of the rear camera installed in the phone. In models with several lenses (see “Number of lenses”), the main one is responsible for basic shooting capabilities and does not have a pronounced specialization (wide-angle, telephoto, etc.). Four main parameters can be indicated here: resolution, aperture ( high aperture optics are quite common), focal length, additional sensor data.

Resolution(in megapixels, MP)
Resolution of the sensor used for the main lens. Budget options are equipped with a module 8 MP and below, many models have 12 MP camera / 13 MP, also recently a trend towards increasing megapixels has been popular. Often in smartphones you can find the main photomodule at 48 MP, 50 MP< /a>, 64 MP and even 108 MP .

The maximum resolution of the resulting image directly depends on the resolution of the sensor; and the high resolution of the "picture", in turn, allows you to better display fine details. On the other hand, an increase in the number of megapixels in itself can lead to a deterioration in the overall image quality - due to the smaller size of each individual pixel, the noise level increases. As a result,...the direct resolution of the camera has little effect on the quality of the shooting - more depends on the physical size of the matrix, the features of the optics and various design tricks used by the manufacturer.

Aperture
Aperture describes the ability of a lens to transmit light. It is written as a fractional number, for example f/1.9. Moreover, the larger the number in the denominator, the lower the aperture ratio, the less light passes through the optics, all other things being equal. For example, an f/2.6 lens will be “darker” than f/1.9.

High aperture gives the camera a number of advantages. First, it improves the quality of shooting in low light. Secondly, it's possible to shoot at low shutter speeds, minimizing the effect of "stirring" and blurring of moving objects in the frame. Thirdly, with fast optics it is easier to achieve a beautiful background blur ("bokeh") — for example, when shooting portraits.

Focal length(in millimetres)
The focal length is a distance between the sensor and the centre of the lens (focused to infinity), at which the most clear image is obtained on the matrix. However, for smartphones, the specifications indicate not the actual, but the so-called equivalent focal length — a conditional indicator recalculated using special formulas. This indicator can be used to evaluate and compare cameras with different sensor sizes (the actual focal length cannot be used for this, since with a different sensor size the same real focal length will correspond to different viewing angles). (It is also worth saying that the equivalent focal length can be noticeably larger than the thickness of the case — there is nothing unusual in this, since this is a conditional, and not a real indicator).

Anyway, the field of view and the degree of magnification directly depend on the equivalent focal length: a larger focal length gives a smaller field of view and a larger size of individual objects that fall into the frame, and a decrease in this distance, in turn, allows you to cover more space. In most modern smartphones, the focal length of the main camera ranges from 13 to 35 mm; if compared with the optics of traditional cameras, then lenses with equivalent focal length up to 25 mm can be attributed to wide-angle lenses, more than 25 mm — to universal models “with a bias towards wide-angle shooting”. Such values are chosen due the fact that smartphones are often used for shooting in cramped conditions, when a fairly large space needs to fit into the frame at a small distance. Enlargement of the picture, if necessary, is most often carried out digitally — due to the reserve of megapixels on the sensor; but there are also models with optical zoom (see below) — for them, not one value is given, but the entire working range of the equivalent focal length (recall, optical zoom is carried out by changing the focal length).

Field of view(in degrees). It characterizes the size of the area covered by the lens, as well as the size of individual objects "seen" by the camera. The larger this field, the more of the scene gets into the frame, but the smaller the individual objects in the image are. The field of view is directly related to the focal length (see above): increasing this distance narrows the field of view of the lens, and vice versa.

Note that this parameter is generally considered important for professional use of the camera rather than for amateur photography. Therefore, viewing angle data is given mainly for smartphones equipped with advanced cameras — including in order to emphasize the high class of cameras. As for specific values, for the main lens they usually are in the range from 70° to 82° — this corresponds to the general specifics of such optics (universal shooting with an emphasis on general scenes and extensive coverage at short distances).

Additional Sensor Data
Additional information regarding the sensor installed in the main lens. This item can specify both the size (in inches) and the sensor model, and sometimes both parameters at once. Anyway, such data is provided only if the device is equipped with a high-end sensor. With the model, everything is quite simple: knowing the name of the sensor, you can find detailed data on it. The size is worth considering a little more.

The size of the sensor is traditionally indicated in fractional parts of an inch — accordingly, for example, a 1/2.3" sensor will be larger than 1/2.6". Larger sensors are considered more advanced, as they provide better image quality at the same resolution. The logic here is simple - due to the large sensor area, each individual pixel is also larger and gets more light, which improves sensitivity and reduces noise. Of course, the actual image quality will also depend on a number of other parameters, but in general, a larger sensor size usually means a more advanced camera. In advanced photo flagships, you can find matrices with a physical size of 1”, which is comparable to image sensors used in top compact cameras with fixed lenses.

Specs of the telephoto lens of the main camera installed in the phone.

These details are relevant only for cameras with several lenses (see "Number of lenses") — and not all, but only those where there is a lens with a large focal length (much larger than in the main lens) and, accordingly, relatively high magnification. In the same paragraph, four main parameters can be indicated: resolution, aperture ratio, focal length and additional sensor data.

Resolution(in megapixels, MP)
The resolution of the sensor used for the telephoto lens.

The maximum resolution of the resulting image directly depends on the resolution of the sensor; and the high resolution of the "picture", in turn, allows you to display small details better. On the other hand, an increase in the number of megapixels in itself can lead to a deterioration in the overall image quality — due to the smaller size of each individual pixel, the noise level increases. As a result, the direct resolution of the camera has little effect on the quality of photos and videos — a lot also depends on the size of the sensor, the features of the optics and various design tricks used by the manufacturer.

As for the resolution of a telephoto lens, it is, usually, somewhat lower than that of the main optics (see "Main lens") or corresponds to it. It does not make sense to provide higher values for a number of reasons — in particular, beca...use a wide-angle main lens requires a fairly significant supply of pixels for digital zoom, and this is not so critical for a telephoto lens — its zoom level itself is quite high.

Aperture
Aperture describes the ability of a lens to transmit light. It is written as a fractional number, for example f/1.9. Moreover, the larger the number in the denominator, the lower the aperture ratio, for example, an f/2.6 lens will transmit less light than f/1.9.

High aperture gives the camera a number of advantages: it allows you to shoot at low shutter speeds, minimizing the likelihood of “shake”, and also makes it easier to shoot in low light and shoot with artistic background blur (bokeh). However, for a telephoto lens, such features are not as important as for the main camera — such lenses usually have a specific purpose, and in this case a large depth of field is often more desirable, achieved just at a small aperture. So in general, this parameter is more of a reference than practically significant when choosing.

Focal length
The focal length is a distance between the sensor and the centre of the lens (focused to infinity), at which the most clear image is obtained on the sensor. However, for smartphones, the specifications indicate not the actual, but the so-called equivalent focal length — a conditional indicator recalculated using special formulas. This indicator can be used to evaluate and compare cameras with different sensor sizes (the actual focal length cannot be used for this, since with a different sensor size the same real focal length will correspond to different viewing angles).

Anyway, the viewing angle and the degree of magnification directly depend on the equivalent focal length: a larger focal length gives a smaller viewing angle and a larger size of individual objects that fall into the frame, and a decrease in this distance, in turn, allows you to cover more space. And since telephoto lenses must provide more magnification than the main optics, they, by definition, have a longer focal length. However compared to classic telephoto lenses for digital cameras, this distance is small — about 50 – 60 mm, or even less than 40 mm (which for a conventional camera corresponds to medium-focus and wide-angle optics, respectively). But this cannot be called a disadvantage, given the peculiarities of filming on smartphones. In addition, there are exceptions — smartphones with "long-range" optics of 80 mm or more, which is already quite a decent indicator for a traditional camera.

Field of view(in degrees) It characterizes the size of the area covered by the lens, as well as the size of individual objects "seen" by the camera. The larger this angle is, the more of the scene gets into the frame, but the smaller the individual objects in the image are. The field of view is directly related to the focal length (see above): increasing this distance narrows the field of view of the lens, and vice versa.

Note that this parameter is generally considered important for professional use of the camera rather than for amateur photography. Therefore, the viewing angle data is given mainly for smartphones equipped with advanced cameras — including in order to emphasize the high class of cameras in this way. Specifically, in telephoto lenses, these angles are relatively small — we recall that high magnification in such optics is achieved precisely by narrowing the field of view. In most cases, the size of this field lies in the range of 45 – 52°.

Additional Sensor Data
Additional information regarding the sensor installed in the telephoto lens. This item can specify both the size (in inches) and the sensor model, and sometimes both parameters at once. Anyway, such data is provided only if the device is equipped with a high-class sensor. With the model, everything is quite simple: knowing the name of the sensor, you can find detailed data on it. The size is worth considering a little more.

The size of the sensor is traditionally indicated in fractional parts of an inch — accordingly, for example, a 1/3.4" sensor will be larger than 1/4". Larger sensors are considered more advanced, as they provide a better image at the same resolution. This is due to the fact that due to the larger sensor area, each individual pixel is also larger and receives more light, which improves sensitivity and reduces noise. Of course, the actual image quality will also depend on a number of other parameters, but in general, a larger sensor size usually means a more advanced camera. However, it should be said that sensors in telephoto lenses are generally noticeably smaller than in main lenses — for example, the mentioned 1/3.4" and 1/4" are quite common options. This is mainly due to the secondary role of such cameras — small sensors are cheaper. In addition, with long-range shooting, a large sensor, for a number of reasons, is not as important as in a regular one.