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SD card capacity. What class of memory card is better to choose - an overview of SD formats

Now almost everyone uses memory cards - everyone has a phone with a camera, a smartphone or a tablet. Well, if you have ever taken a memory card in your hands, then you know that many different letters and numbers are written on it. What do they mean and what can they tell the owner? Now I will tell you about decoding the marking of Secure Digital (or just SD) and MicroSD memory cards, after which, I think, you should no longer have any questions. Almost all of them are identical for other memory card standards like Compact Flash, Trans Flash, Memory Stick, etc.
So, as you already guessed, everything that is written on the memory card is not just a set of symbols, but its key parameters. Deciphering the markings will tell a literate person everything about her from just one glance!

There are six such parameter-tags on a regular SD-card (6). Let's take a closer look at each of them:

1. Memory card capacity - this is probably the most important and common marking that you will see on a memory card. It indicates the amount of removable storage - that is, the maximum size of data that it can store. But here you need to take into account the following feature - the actual (usable) storage space that you get will be less than the specified capacity on the card. Why it happens? The fact is that this difference will be occupied by the file system used on the device. And the larger its volume, the more the file system eats away.

2. Write protection icon. You can find such a marking in the form of a lock on an SD-card, it will not be on a small MicroSD card! This is a write-protect symbol and is usually drawn on the left side of the card case along with a downward arrow. If the tiny lever is in the up position, recording is possible; if in the down position, the disc is locked and write protected.

3. Declared reading speed. In the upper left corner of the card, you can see the number of megabytes per second - this is the maximum read speed that an SD card can develop. It is not at all a fact that you will be able to achieve it. The measurement was carried out on the basis of internal manufacturer testing and may also differ from the real one!

Attention! It should be borne in mind that the read speed is different from the write speed. Manufacturers usually do not specify the latter parameter, since the write speed of an SD card is usually significantly lower in value (i.e. slower) than the read speed.

4. Card format. It has been almost two decades since the creation of SD cards. Agree, in the field of digital technologies this is a huge time. During this time, the standard has evolved in accordance with consumer needs for faster gadgets and for storing large amounts of information. With each new development, the Association creates a new format to standardize the next generation SD card.

There are currently three SD formats:

Secure Digital Standard Capacity (SDSC or SD only) - uses FAT 12/16 file systems and has a capacity of up to 2 GB;

Secure Digital High Capacity (SDHC) - Uses FAT32 file system and supports up to 32GB;

Secure Digital Extreme Capacity (SDXC) - uses exFAT format and can be up to 2 TB.

5. Speed \u200b\u200bclass. Next, we have the speed class marking, which gives a rough idea of \u200b\u200bthe minimum write speed performance and its compatibility with the main device. There are currently four (4) speed classes defined by the SD Association - Class 2, Class 4, Class 6 and Class 10.

Class 2: 2MB / s Class 4: 4MB / s Class 6: 6MB / s Class 10: 10MB / s

6. UHS class. Recently, the last sixth parameter has been added - Ultra High Speed \u200b\u200bor UHS Class. What is UHS ?! This is a special class created by the Association in 2009 that offers faster bit rates for SDHC and SDXC and is designed for high definition video recording.

There are now two classes of UHS; UHS Speed \u200b\u200bClass 1 (U1) and UHS Speed \u200b\u200bClass 3 (U3). Similar to the speed classes, the maximum speed of UHS SD cards can only be achieved if the host device supports UHS technology.

How to understand the class of the card, what is UHS and how to choose the best card at the lowest price.

We will tell everything using examples of Toshiba SD cards. All data is relevant for CF and other types of cards.

The card always has the card type, baud rate, card class and bus specified.

Card types

There are three types of SD cards in total:

SD - the very first memory cards, compatible with all devices. Capacities up to 2GB.
SDHC - SD High Capacity - cards of increased capacity. Capacity 4 - 32 GB.
SDXC - SD Extended Capacity - extended capacity cards. Capacity 32GB - 4TB.

Speed

For photography, the recording speed with which the camera will save data is important.

On maps, the speed can be indicated directly, for example, 95 Mb / s.

You can also find cards in which the speed of work is indicated in multiples, for example, 600x. The multiplicity is always one x \u003d 150 kb / s.

100x \u003d 100 x 0.15 kbps \u003d 15 Mbps. This speed started with CD-ROMs (things that were before the iPod and long before the iPhone). Maximum multiple speed - 633x (95 MB / s). For CF cards, the maximum multiple speed is 1066x (160 MB / s).

For example, Toshiba EXCERIA PRO UHS-II 16GB. Reading and writing speeds are 260 and 240 MB / s, respectively. This means that a gigabyte of data will be written to the card in 4 seconds. The main thing is that your camera supports such a speed and a bus (you will learn about it below).

Map class

The card class indicates the minimum guaranteed streaming write speed. For example, Class 10 corresponds to a speed of 10 Mb / s.

For video, it is not the peak rate that is important, but the streaming recording rate, otherwise there will be frame loss.

Since 2009, additional classes U1 and U3 have been introduced for SD cards (based on the new high-speed UHS bus). Classes provide a minimum speed of 10 and 30 Mb / s, respectively.

Example. Toshiba EXCERIA UHS-I. The card uses UHS speed class 3, which provides a minimum speed of 30 Mb / s. and although its maximum read and write speeds are 60 and 95 MB / s, this card is capable of recording 4K video.

Below is a table of correspondence between class and minimum streaming write speed.

Recently, SD has developed new standards for card classes that will enable video capture in 8K resolution.

What is UHS

UHS - (Ultra High Speed) ultra high speed bus that provides the fastest recording speed.

UHS-I supports speeds up to 104MB / s
UHS-II supports up to 312 MB / s.

UHS-II cards can be distinguished by their two rows of pins.

Example

As you can see here the speed is 260 Mb / s. Roman I stands for UHS-I class. And the U3 shows that the card supports 4K video.

Which card to choose

Shooting FullHD video - cards Class 10, or class U1 of the EXCERIA series.
Fastest Photo Write Speed \u200b\u200b- Choose UHS-II cards with the EXCERIA PRO Series Fastest Speed.
Shooting 4K video - EXCERIA U3 class cards.
High speed recording + 4K video - EXCERIA PRO series U3 cards and UHS-II bus.

Let's try to find out what class of memory card you should equip your smartphone, tablet, laptop, camcorder or camera, when such a need arises, and what class of memory card is best for each of these devices?

To do this, let us consider in detail what classification of memory cards currently exists, and how one miniature storage device differs from another.

Before you know what the class of a storage device means, you should clarify the concept of media speed. There are two different values \u200b\u200bfor this parameter, the first is the read or data transfer rate, and the second is the data write rate. The read speed is almost always faster than the write speed, while it is not directly related to the class of equipment: it may even turn out that a USB flash drive with the designation "class 4" will be read faster than a class 10 flash drive.

Of the two numbers describing the characteristics of the medium, this will be the larger number: the higher the read speed, the easier and faster you can transfer information to an external device. Recording speed is important to the performance of your hardware, and it is this speed that allows you to record high definition video. You can find out if the manufacturer offers a good high-speed recording mode by looking at the back of the package.

Since some unscrupulous manufacturers indicate inflated specifications on their products, it is better to purchase memory cards of well-known brands, but, in any case, it is always possible to check the speed data yourself. Checking the speed is easy with the help of special programs, for example, USB-Flash-Banchmark and Check Flash, which can be downloaded for free, or the H2testw utility.

Existing card types

Modern digital media can be of different sizes: mini, micro and full-format, while the smallest dimensions are designed for a smartphone, tablet or mobile phone, and those that are larger are used in camcorders and cameras.

For a long time, the main storage medium was CompactFlash, or CF cards, measuring 43 x 36 x 3.3 mm, and although the age of these formats has passed, nevertheless, they are still used in some DVRs today.

The most common type of digital storage equipment today is the SD Card (Secure Digital Memory Card) or SD card.

This device, which does not exceed the size of a postage stamp, measures 32 x 24 x 2.1 mm, surpassed the CF card in all respects, and almost all modern technology is compatible with it. Higher capacity devices have come to be referred to as SDHC, and ultra high capacity devices have come to be referred to as SDXC.

A Micro SD or micro SD card is simply a miniature version of an SD card, measuring 11 x 15 x 1 mm, which is inserted into devices with limited space, such as phones. However, if necessary, it can be installed even in a laptop, if you use a special existing adapter for this. There is also a mini SD with dimensions of 21.5 x 20 x 1.4 mm, since some types of equipment are equipped with just such slots.

Classes of SD memory cards

Let's say that we already know what size the storage device should be, how much memory we need for optimal operation. It remains only to find out what the class of the memory card is, what this parameter of the SD card affects, in order to choose the necessary one. It is from this characteristic that the speed at which we can transmit or receive the information of interest to us will depend.

So, this is a parameter that determines the degree of speed of the SD memory card, according to which all devices are divided into:

Class 2 - speed from 2 mb / s to 4 mb / s. Since the write speed is very low, this class of flash drive should not be used in camcorders or digital cameras. The lack of speed is compensated by the relative cheapness of the card, so it can be safely used to reproduce sound and images, that is, in audio or video players, since in this case high speed is not needed.
Class 4 - speed from 4 Mb / s and above. For amateur home photography in digital cameras, class four can be used. The fourth class, in addition, is installed in a video recorder and some inexpensive non-professional video cameras.
Class 6 - guaranteed speed from 6 Mb / s and above. A flash drive of this level can already be installed in semi-professional camcorders and SLR cameras that shoot in RAW format. They allow you to get a fairly high quality of shooting.
Class 10 - speed ranges from 10 Mb / s and above. A class 10 flash drive can be equipped with a car recorder, professional video and photo equipment with Full HD recording. Class 10 allows for burst photography, RAW shooting and image saving, which is of great importance for professional photographers. However, such devices are somewhat more expensive, for example, a microsdhc class 10 memory card will cost at least 1000 rubles.
SD Class 16 - the speed is not less than 16 Mb / s, but it is still very difficult to buy this card in our country, since it has not yet been widely sold.
Ultra High Speed \u200b\u200b(UHS) - These ultra high speed cards can only be used with compatible devices, which is usually described in the instructions. Class 10 UHS I is a high speed card that can write speeds up to 50MB / s or more.

There is a UHS specification that regulates the speed of the equipment. According to the UHS-I standard, the data exchange rate must be at least 50 Mb / s and up to 104 Mb / s, according to the UHS-II standard - at least 156 Mb / s and up to 312 Mb / s. The class 10 uhs i card allows for the highest level of real-time recording and, in addition, for large-size HD video.

How to determine the class of a memory card? You just need to look at it carefully: the number circled in the front of the digital storage medium will be the desired value.

How to choose a USB flash drive

Please note that the latest memory device formats may not work with older hardware. For example, if a smartphone supports micro SD, this does not mean that it will also support high-speed micro SDXC. Therefore, to find out such a possibility, it is better to familiarize yourself with the documentation for the smartphone in advance.

Micro SD, as well as SD media, come in two formats (SDHC up to 32 GB and SDXC from 64 to 512 GB) and are used in all modern smartphones and tablets. The tenth speed class of such information carriers is no different from their full-size counterparts. Thus, the higher the classes of sdhc memory cards, the sooner the data transfer takes place, which is the main advantage of those micro SD cards that are more expensive with the same capacity.

For example, a microsdhc class 10 32GB memory card, costing about 1500 rubles. Ideal for modern digital devices such as phones, camcorders, smartphones, PDAs, audio players and game consoles. If you do not skimp on the class of equipment, pursuing immediate benefits, you can get long-term excellent results in the further use of technology: high-quality images and stunning videos, as well as the proceeds from their sale.

Every owner of a digital camera or smartphone with a camera sooner or later thinks about buying a memory card. Even if the device already has several gigabytes of internal memory, you will need a large flash drive with a high recording speed to save photos and videos. It may seem that all the cards are the same, but there are many pitfalls in this topic. We'll show you how to choose the best memory card.

MEMORY CARD TYPE

There are several types of memory cards on the market today. The one specified in the description of your device will suit you. For example, most cameras today are compatible with SD (Secure Digital) memory cards, which have two subtypes: SDHC (high-capacity cards) and SDXC (extra-large-capacity cards). Cameras released several years ago may not be compatible with SDXC memory cards, and digital camera models released before 2006 may not be SDHC compatible.

The maximum capacity for SDHC is 64 GB, and for SDXC is 512 GB.

In some professional cameras, as well as in cameras of the past, CF (Compact Flash) flash drives are widely used. Today they are not much superior in their characteristics to other types, however, they are the first in terms of volume and recording speed. However, before purchasing a fast CF memory card, make sure your camera can handle this fast transfer rate. In particular, there must be support for the UDMA (Direct Memory Access) function from the camera.

There are also CFast 2.0 memory cards with ultra-high read (up to 515 MB / s) and write (up to 440 MB / s) speeds. Their maximum size is 128 GB, the minimum is 64 GB. This is a relatively new format and is supported by several professional cameras. But it is already clear that due to its high speed characteristics, it will be in demand in the future.

Canon EOS-1D X Mark II / EF100-400mm f / 4.5-5.6L IS II USM SETTINGS ISO 1000, F6.3, 1/1000 sec.

In tablets and smartphones, where compactness is especially important, along with ordinary SD cards, their smaller versions - microSD can be used. They are often used in action cameras and some pocket cameras. Today, microSD cards are not inferior to their full-size counterparts in anything - neither speed nor volume. They can also be used in cameras with a standard SD slot via an adapter. The maximum microSD memory capacity is 200GB on the SanDisk Ultra microSDHC / microSDXC UHS-I model. You can read more about microSD memory cards on the pages of our magazine.

MEMORY CARD STANDARD UHS-I and UHS-II

Today UHS-II memory cards are being actively introduced. Fujifilm X-T1, Fujifilm X-Pro2 and Olympus OM-D E-M5 Mark II are already working with them. The file writing speed reaches 250 MB / s, and the read speed reaches 280 MB / s. Such high rates make it possible to realize all the possibilities of modern technology. Externally, flash drives of the old and new standards are no different, but this is only on the front side. On the back of UHS-II cards, the contacts are arranged in two rows. But most importantly, UHS-II is backward compatible: they can be used in cameras and camcorders that do not support this standard. Obviously, the future belongs to them.

Some manufacturers of photographic equipment have tried to introduce their own types of flash drives. But at the moment, almost all camera models are compatible with one of the above types, and for using your own types of flash drives, either a separate or a combined slot is provided.

WHAT AMOUNT OF MEMORY CARD TO CHOOSE?

The size of the memory card determines how many pictures or minutes of video you can record. Naturally, more capacious cards are more expensive. But we live in the age of multi-megapixel cameras and the upcoming era of 4K video. SLR cameras have crossed the 50 megapixel line, and mirrorless cameras are already equipped with 42 megapixel sensors. And even in mobile phones, you can find the resolution of images over 40 million pixels! The average number of pixels is 24 million. Canon EOS-1D X Mark II writes video at 800 Mbps. One forty-second video from this camera takes about 5 GB! And the higher the resolution of the picture and video, the more space will be required on the flash drive.

The size of a file directly depends on the number of details stored in it, that is, on its quality. If you shoot photos in RAW + JPEG format, the size of one shot can be over 100 MB! Now there is an ultra-high definition 4K video format, where one minute can take up the volume of an average amateur photo session.

It makes little sense to purchase memory cards with a volume of less than 16 GB today. If you plan to actively take pictures and shoot a little video, then we recommend memory cards with a capacity of 16 and 32 GB. In this case, you should not shoot all the material on one card, it is better to split the session into several flash drives. The point is not so much the unreliability of memory cards (they are just very reliable), but rather the fact that we can lose them. When shooting video, the size of the memory card should be selected so that it is enough for the entire shooting day. Below we give a table for modern multi-megapixel cameras, which will allow you to roughly estimate how many pictures and minutes of video can be recorded on memory cards of different sizes.

Memory capacity	Full HD H.264 video	Photo RAW + JPEG
8 GB	10 minutes	80 photos
16 GB	21 minutes	160 photos
32 GB	43 minutes	320 photos
64 GB	1 hour 27 minutes	650 photos
128 GB	2 hours 54 minutes	1280 photos

HOW TO DETERMINE THE OPTIMUM WRITING AND READING SPEED?

Many people don't pay attention to the speed of the memory card. But in vain, because it is more important than volume, because it determines the scope of the flash drive. For example, you won't be able to record Full HD on a slow card - the recording will be constantly interrupted. If you shoot a series of frames with a slow flash drive, the camera may freeze for a long time while recording it. Once we had to wait three whole minutes for a series of images from a 42-megapixel camera to be recorded onto a Class 10 card. High-speed photography of more than 10 frames per second is no longer surprising, and 4K and 360 ° video formats raised the bar for recording speed to new heights. So how can you tell a fast memory card from a slow one and find the best one for your device?

Previously, flash cards were divided into classes: 2, 4, 6 and 10. In fact, this is the write speed in megabytes per second: class 2 - 2 MB / s, class 6 - 6 MB / s. The tenth grade implies that a flash drive can record pictures at a higher speed than 10 MB / s. Such fast flash drives, in addition to the letter C, are marked with the letter U with the number 1 or 3. The manufacturer always indicates on the card the real read and write speed (for example, 45 MB / s), and on the right - the class of the card. The situation is similar with Compact Flash and microSD.

HOW DO I CHOOSE THE SPEED CLASS OF THE MEMORY CARD?

If you plan to shoot video in Full HD format, then a memory card of at least speed class 6, and better - 10 or higher, is suitable for you. The same maps are suitable for everyday shooting. For burst shooting, it is better to choose faster flash drives - about 45 MB / s. This will allow you to photograph in short, continuous bursts. With slow flash drives, you run the risk of missing an interesting shot while your camera is recording previous shots.

Shooting moving objects places even greater demands on speed: you have to shoot almost continuously in burst. And here the ideal speed of a memory card is already 80 MB / s and higher.

Finally, for professionals shooting long bursts, the fastest flash drives with speeds of 90 MB / s and above are essential. Writing speed is key and you shouldn't skimp on it. A professional camera with a high-speed memory card is able to shoot a continuous series of frames until it runs out of free space.

Reading speed is less important for the camera. It is always higher or equal to the write speed. By choosing a memory card with a high write speed, you will definitely not experience problems with reading speed.

WHAT TO PAY ATTENTION TO?

As long as the memory card is inside the device, it is protected. But as soon as it is removed, it immediately becomes vulnerable. The photographer will drop it at least once, but leave it on the table under the scorching sun, in a photo bag in severe frost, or even worse - douse it with water! What can we say about travel: at the airport, luggage will be illuminated with X-rays. We recommend choosing memory cards that are protected against all of these negative influences.

WHICH MEMORY CARD MANUFACTURER TO CHOOSE?

Prophotos recommends SanDisk memory cards. With them, we have been testing all cameras that come to our editorial office for many years, because we trust their reliability and value high performance. Below are recommendations for different types of devices.

The following memory card models are ideal for digital SLR cameras with interchangeable lenses: SanDisk Extreme PRO microSDXC UHS-II, SanDisk Extreme PRO SDHC / SDXC UHS-I, SanDisk Extreme PRO SDHC / SDXC UHS-II, SanDisk Extreme Plus SDHC / SDXC UHS- I, SanDisk Extreme microSDHC / microSDXC UHS-I, SanDisk Extreme Pro CompactFlash, SanDisk Extreme Plus microSDHC / microSDXC UHS-I, SanDisk Extreme SDHC / SDXC UHS-I, SanDisk Extreme CompactFlash.

For amateur photo and video shooting, depending on the type of camera, suitable: SanDisk Extreme Plus microSDHC / microSDXC UHS-I, SanDisk Extreme Plus SDHC / SDXC UHS-I, SanDisk Ultra PLUS microSDHC / microSDXC UHS-I, SanDisk Ultra PLUS SDHC / SDXC, SanDisk Ultra microSDHC / microSDXC UHS-I, SanDisk Extreme microSDHC / microSDXC UHS-I, SanDisk Extreme SDHC / SDXC UHS-I, SanDisk Ultra microSDHC / microSDXC UHS-I, SanDisk Ultra SDHC / SDXC, SanDisk microHCD / microSD.

For professional video shooting: SanDisk Extreme PRO SDHC / SDXC UHS-I, SanDisk Extreme PRO SDHC / SDXC UHS-II, SanDisk Extreme PRO Compact Flash, SanDisk Extreme PRO CFast2.0, SanDisk Extreme PLUS SDHC / SDXC UHS-I, SanDisk Extreme SDHC / SDXC UHS-I, SanDisk Extreme CompactFlash.

The following memory cards are ideal for action cameras: SanDisk Extreme PRO microSDXC UHS-II, SanDisk Extreme PLUS microSDHC / microSDXC UHS-I, SanDisk Extreme microSDHC / microSDXC UHS-I, SanDisk Ultra PLUS microSDHC / microSDXC UHS-I, SanHDisk Ultra microSDXC / microSDXC UHS-I.

Today's article is a short educational program on sD memory cards... These flash cards are widely used in modern technology: in mobile phones, GPS-navigators, cameras and camcorders.

SD is by far the most popular memory card standard today. The vast majority of devices working with memory cards support this standard.

SD memory cards come in three different sizes. This made it possible to cover various devices: from miniature audio players to professional video cameras.

So what are there sD card form factors :

microSD - these cards are intended for use in mobile phones, smartphones, tablets and other compact devices.

- these cards are slightly larger than microSD cards. Until recently, they were used in mp3 players and other portable equipment. But today they have lost their popularity and are used less and less.

SD - maps of the largest size. They are used in cameras, camcorders, video recorders and other relatively large portable equipment. New generation cards SDHC and SDXC are exactly the same size as SD.

By the way, a device designed to work with large SD cards, you can insert a card of a smaller form factor. To do this, you need to use a special adapter:But it is better not to do this without unnecessary necessity, because microSD cards are usually much slower than full-fledged SD cards.

Exist four generations of SD cards :

SD 1.0 - holds the amount of information from 8 MB to 2 GB
SD 1.1 - up to 4 GB
SDHC - up to 32 GB
SDXC - up to 2 TB

In the case of SD cards, there is backward compatibility: i.e. SDXC capable devices understand SDHC and the older SD format (but not vice versa!).

Memory cards differ not only in size or capacity. One of the main parameters is speed exchange information with the device.

SD card speed manufacturers designate either as class, or in the form multiplier:

SD Class 2 - recording speed not less 2 MB /with 13x;
SD Class 4 - recording speed not less 4 MB / s, which corresponds to the factor 26x;
SD Class 6 - recording speed not less 6 MB / s, which corresponds to the factor 40x;
SD Class 10 - recording speed not less 10 MB / s, which corresponds to the factor 66x;
SD Class 16 - recording speed not less 16 MB / s, which corresponds to the factor 106x.

As you can see, the speed class of the card directly indicates the speed of its operation in MB / s. To find out what class your memory card has - just look at its front part: it should be indicated there. For example, in this case, the card tenth grade of speed:

Before buying an SD memory card, you need to know which speed class your device requires. This information should be indicated in the instructions for it.

The speed class is important for those who are going to shoot video. For example, recording Full HD video requires a write speed of 3 MB / sec, which is equivalent to a Class 4 memory card. Using a slower card will cause problems when shooting. However, in some cases, the video stream speed can be up to 6 MB / s. Therefore, for video shooting, it is better to buy memory cards starting from Class 6 and higher.

How upload information directly from the SD card to the computer? For this, there are special devices called card readers... The card reader can be either external (connected via a USB connector) or built into a computer or laptop.

After connecting the card reader to the computer, insert your memory card into the corresponding slot. After that, go to Windows in “Computer” - the flash drive will appear in the “Devices with removable media” section. You can open it and perform file operations.

built-in internal card reader

In conclusion, I would like to say that when buying an SD card, it is better not to pursue cheapness, but to purchase a card from a well-known manufacturer (I would recommend Transcend). Because losing captured photos or videos due to a broken card will be very offensive.

01.11.2020

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