The most widely used on board cameras are Secure Digital drives - the notorious SD cards and their miniature versions microSD. As a rule, flash drives of the second order are installed in the camera slot using an adapter for an "adult" SD size. The progenitors of these drives were MMC cards. Today this is a “dead” type and such flash drives are almost never used, so let's go straight to the consideration of SD drives:

SD and microSD (Secure Digital)

In an era of solid footing of the portable electronics industry, SanDisk, Toshiba and Matsushita (now Panasonic) joined forces to create a single standard for memory cards. So in 1999, the debut of the SD drive took place. The format and dimensions of the MultiMedia Card were taken as the basis for its development - 32x24x2.1 mm. The competitive advantage of SD flash drives is the presence of a built-in microcontroller and a special protected area that prevents unauthorized access to data. The overwrite protection function is enabled by a special slider on the body of the flash drive - in the "Lock" mode, writing and deleting content from the card becomes impossible.

In the lower position, the "Lock" slider blocks the recording and deletion of data from the memory card.

We revealed the whole ins and outs of SD flash drives in the material “MicroSD, SD or CompactFlash? How to choose the right memory card for your smartphone, camera, camcorder and other equipment. In order not to repeat ourselves, we highlight the characteristic features of Secure Digital drives.

So, SD memory cards are produced in the following dimensional grid:

  • SD - 32x24x2.1 mm (suitable size for cameras and camcorders);
  • miniSD - 21.5x20x1.4 mm (outdated form factor, which is now almost nowhere to be found);
  • microSD - 11x15x1 mm (flash drives for smartphones, action cameras, DVRs, etc.).

By generation, SD drives are divided into three groups:

  • Classic SD - cards with storage up to 4 GB, formatted in FAT16.
  • SDHC (Secure Digital High Capacity) - flash drives from 4 to 32 GB formatted FAT32. Such cards have been produced since 2006, the maximum weight of an integral file on them does not exceed 4 GB, which imposes certain restrictions on video shooting.
  • SDXC (Secure Digital eXtendet Capacity) - drives with a capacity of 64 GB to 2 TB with the exFAT file system. These flash drives have been on the market since 2009, and they are also backward compatible with earlier generations of SD.

According to the speed indicators of work, there is a gradation of SD-drives by class. At first, they were simply designated: Class 2, Class 4, Class 6, Class 10 and Class 16. The number near the class label is the minimum guaranteed speed of writing data to a flash drive in MB / s. With the development of SD cards, a more relevant division into UHS (Ultra High Speed) classes has appeared. At the moment, there are three generally accepted speed classes:

  • UHS-I Class 1 (U1) - minimum write speed from 10 MB / s, maximum - 50 or 104 MB / s (depending on the architecture of the drive).
  • UHS-I Class 3 (U3) - the throughput of flash drives with such a label starts from 30 MB / s and is up to 104 MB / s.
  • UHS-II Class 3 (U3) are the fastest cards with stable data write speeds from 30 MB/s with maximum overclocking up to 156 or 312 MB/s (depending on architecture).
An interesting point. An advanced sub-type of SDXC memory cards with increased data processing speed (up to 312 Mb / s) was released in 2013. A distinctive feature of its character is the presence of an additional row of contacts: 17 for a standard form factor and 16 for microSD.

On the body of the flash drive, support for a certain UHS class is indicated by the numbers "1" or "3", which are placed inside the letter "U". The higher the speed class of the drive, the better it is adapted to quickly save large amounts of information, whether it's a series of "heavy" RAW shots or recording 4K video with a high frame rate. By the way, another classification of SD and microSD cards has been adopted by a specialist for videographers. We are talking about video recording class V. The number after this letter of the Latin alphabet also indicates the guaranteed speed of writing data to a USB flash drive in MB / s. For example, for comfortable shooting video in Full HD resolution, a card marked V10 will be enough, to record 4K video you will need a V30 or V60 class drive, and flash drives of the V90 class work with large high-resolution files.

V90 branded SD drives are the fastest memory cards for high-definition video recording.

Modern cameras are compatible with all types of SD cards. The exception to the rule is the UHS-II class (relatively expensive and rare memory cards that reveal their potential only with top-end DSLRs and mirrorless cameras). On board devices without support for the aforementioned standard, such flash drives operate via the UHS-I interface with a slightly lower data exchange rate.

As for the reduced form factor microSD, it is applicable in cameras through an adapter to the size of SD. The disadvantages of microSD include a slightly lower write and read speed, which is not particularly critical in practice.

CF (Compact Flash)

Compact Flash memory cards appeared about five years earlier than SD drives. The format was developed by SanDisk Corporation in 1994. Despite their considerable age (by the standards of the impressively rapid evolution of electronics), CF flash drives are still in demand today. The secret of their success is the winning combination of high capacity, excellent reliability and high speed data exchange.

There are two formats of Compact Flash cards:

  • Type I with dimensions 43x36x3x3 mm;
  • Type II - 43x36x5 mm.

In the "wild nature" there are CF drives of the first type, the second subspecies is practically not used in technology. The speed classes of CF flash drives are usually denoted by multipliers: 100x, 266x, etc. The value of 150 kb / s acts as an "X" - the minimum speed for playing a CD, which was customary to be equal to at the time of the appearance of Compact Flash cards. Using simple mathematical calculations, you can determine the speed indicators of data handling by multiplying the number in front of the "x" by a value of 150 kB / s.

1066x CF flash drives are the fastest in the class.

Top CF drives can have a multiplier of 1066x - reading information from such cards is carried out at a peak speed of up to 160 MB / s. However, such flash drives are not cheap. Another disadvantage of Compact Flash cards is the physically large size of the format, which is why manufacturers of equipment need to allocate a lot of space for a memory card. As a result, CF remains the domain of professional photography and videography.

The video recording classes of CF drives are graded according to the VPG (Video Performance Guarantee) scale. The scheme here is standard - the number after the VPG abbreviation indicates the minimum guaranteed rate of data writing to a USB flash drive in MB / s. VPG20 class drives can confidently shoot video in Full HD resolution, VPG65 cards will pull 4K video, and VPG130 class flash drives are used in professional video production.

Based on Compact Flash, high-speed CFast 2.0 drives are produced.

In the course of evolution based on Compact Flash, a new CFast format was released using the SATA architecture. Cards of this order are incompatible with CF in terms of contact groups: they have a standard 7-pin SATA interface connector and a 17-pin power connector. With the help of an adapter, it is quite possible to use them as a drive for a computer. Original CFast drives are a rarity. Today, CFast 2.0 cards with a data exchange rate of over 500 MB / s predominate on the shelves of electronics stores. For example, there is a slot for such drives on board the flagship SLR "monster" Canon EOS 1D X Mark II.

XQD and CFexpress

With an emphasis on high speed data exchange in 2010-2011. SanDisk, Sony and Nikon have developed and approved the XQD drive format. It is a logical development of the Compact Flash standard, the speed of reading and writing data to the corresponding cards often exceeds 400 MB / s. High performance makes XQD drives excellent solutions for burst photography and video recording without the risk of the slightest frame drop.

XQD cards develop a read and write speed of about 400 MB / s.

At the top of Olympus, XQD cards did not last long - they were replaced by CFexpress drives. These are impressively fast sticks with an eye for long continuous recording in intensive mode.

CFexpress memory cards are available in three different sizes:

  • CFexpress Type A - 20x28x2.8 mm, have a write speed of up to 1 GB / s (used in cameras Sony A7 III, Sony A1, etc.);
  • CFexpress Type B - 38.5x29.8x3.8 mm with a write speed of up to 2 GB / s (suitable for cameras Nikon D600, Nikon Z6 II, etc.);
  • CFexpress Type C - 54x74x5.8 mm with data transfer rates up to 4 GB / s (designed to work with computers and SSDs).

Almost all cameras that work with XQD have received support for CFexpress Type B in the new firmware.

Rugged and fast, CFexpress drives are often built to handle the toughest shooting conditions.

Drives of this format are best suited for shooting video in 4K resolution and more with high bitrates and frame rates from 120 fps. Also, the cards of the line are characterized by resistance to damage during falls and high bending strength of the case. It is only necessary to put up with the exorbitant cost of CFexpress cards.

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Choose the right memory cards for your camera, use them wisely, and keep a spare flash drive or two in your stash. Give preference to products of well-known brands, especially when it comes to expensive XQD and CFexpress drives - many venerable manufacturers provide a long-term warranty (including a lifetime one) on memory cards and easily change a failed flash drive to a new one. Whereas no one is responsible for the reliable operation of drives from a conditional Chinese online store.