Enter ePz's Christmas Prize Draw! Plus, a prize for all on Xmas day!

Complete Guide To Memory Cards

The complete guide to memory cards - There are many options used in cameras to store your images. Here we provide a round up of the various memory cards and their benefits, including SD, MicroSD, XQD, CompactFlash and more.

|  Memory Cards
 Add Comment

Memory cards side by side

Main memory card types: MicroSD, SD, XQD, CompactFlash

Memory cards are the main format used to store and exchange digital data: MP3 music files, photos and personal content such as word files, contact lists etc. Today you will find memory card ‘slots’ in digital cameras, mobile phones, MP3 players, tablets, notebook computers and many more devices. This overview should help you make sense of the various options available to you in the market today.

Flash Memory. Although of all memory card types only ‘Compact Flash’ cards actually bear the name, all memory cards (and sticks) are based on Flash technology. Many other devices such as USB Flash drives and MP3 players use Flash memory. However, as our focus is on memory cards, the various types of Flash cards we can discern today are:


Secure Digital Cards (SD / SDHC / SDXC)

Samsung SD Memory Card

Secure Digital or SD cards are much smaller than Compact Flash cards and were originally often found in smaller devices such as mobile phones and MP3 players, but have now become the most used option in compact digital cameras.

What's the difference between SD, SDHC and SDXC? 

  • SD cards offer up to 2GB 
  • SDHC cards offer sizes between 4GB+ and 32GB
  • SDXC cards offers sizes between 32GB and 512GB+

It's important to check that your camera supports SDXC before buying as not all cameras support it - you may also need to update your PC to support SDXC (Update available from Windows).

Eye-Fi cards have built in Wi-Fi, making it possible to transfer images straight from the camera, even if the camera doesn't have Wi-Fi built in, although the camera does need to support the card for it to work. See our Eye-Fi review.

Damaged SD cards

SD cards, particularly the cheaper cards, are often quite fragile, so it's important to take care of them, either by leaving them in your camera, or storing them in a protective case. Some brands, that aren't specifically made to be tough may split, and damage to the plastic spacers between the contacts is quite common. Samsung offer waterproof, shockproof, magnet proof, xray proof and dustproof memory cards, in both SD and MicroSD formats, with a 10 year warranty.



Shown above, left: The rear of a UHS-I card, and right: The rear of a UHS-II card. The UHS-II card is backwards compatible with older cameras, so you can still use UHS-II memory cards in older cameras. However, to take advantage of the higher read/write speeds of UHS-II cards, you will need a camera compatible with UHS-II cards, as well as a UHS-II memory card reader for your PC. Cameras that support UHS-II memory cards include the following: Fujifilm X-T1, Fujifilm X-Pro2, and Samsung NX1Find the Top 10 Best SD cards here.

Buy Value SD Memory Cards   Buy Waterproof Memory Cards   Buy Professional Memory Cards


MicroSD (MicroSDHC / MicroSDXC)

Samsung Waterproof MicroSD

These are often used in mobile phones, smartphones and compact cameras. They are extremely small, as you can see above - this makes them more suited to mobile phones or cameras where you don't plan on removing or swapping the card. They often come with a MicroSD to SD adapter so you can use them in normal SD cameras or readers. Like SD, they also have Class speed ratings (see below), and you'll need to make sure your device supports SDHC and SDXC.

What's the difference between MicroSD, MicroSDHC and MicroSDXC? 

  • SD cards offer up to 2GB 
  • SDHC cards offer sizes between 4GB+ and 32GB
  • SDXC cards offers sizes between 32GB and 512GB+

 Find the Top 10 Best MicroSD cards here.

Buy a Value MicroSD Card   Buy a Waterproof MicroSD Card   Buy a Professional MicroSD Card


CompactFlash Cards (CF)

CompactFlash Memory Cards

Compact Flash or CF cards are popular in devices that can spare a bit more space inside, as despite their name, Compact Flash cards are among the largest cards in terms of physical size. Compact Flash cards offer a significant range of speeds and capacities, up to 256GB+ and 160Mb/second – but more about speeds and capacities later. Important to note is that Compact Flash cards come as type I cards and type II. Type II cards typically allow higher storage capacities but are also physically a much thicker card. When buying a CF card, it is therefore important that you check which type of CF card your device supports. Find the Top 10 Best Compact Flash cards here.

Buy a Professional CF Card   Buy a High-speed CF Card   Buy a Value CF Card


XQD Cards

Sony XQD Memory Card

XQD memory cards are a new format, designed for high speed read and write, making them suitable for high resolution (4K) video recording, as well as cameras with high speed continuous shooting. The cards are available from Sony and Lexar, and are supported by the Nikon D4, Nikon D4s, Nikon D5 and Nikon D500. They are available with different speeds, with the Sony G series offering the fastest speeds. Sony XQD vs Lexar CompactFlash Review

Buy Sony N Series XQD Cards   Buy Sony M Series XQD Cards   Buy Sony G Series XQD Cards


Memory Stick

Memory Sticks (MS) were developed by Sony, to provide flexible storage for many of their products. Memory sticks are found in a variety of devices and offer great versatility – but unfortunately there's a lot of confusion as well, as Memory Sticks have appeared in a number of different formats. Physically speaking, there is the standard Memory Stick, this was joined by Memory Stick Duo (now discontinued), Memory Stick PRO, Memory Stick PRO-HG and Memory Stick Micro M2 which is shorter and thinner. There are also differences in the ‘controller’ software on various Memory Sticks.

Memory Stick Duo came as a standard MS Duo or an MS Duo Pro (sometimes also called Pro Duo). MS Duo Pro often came with an adapter that let you use the MS Duo Pro as an MS Pro – the controller software was the same.

Memory Stick PRO-HG is designed for high-speed data transfer based with Memory Stick PRO format technology and Memory Stick PRO-HG Duo media can also be used with Memory Stick PRO compatible products. More recently Sony has supported both SD/SDHC and Sony Memory sticks in their cameras.

Buy a Sony Memory Stick

Note 1: Users often wonder if their device, which their manual states supports either Memory Stick or Memory Stick Duo, will also accept MS Pro or MS Duo Pro, so that they can take advantage of the larger capacities available in the ‘Pro’ sticks (See capacity below). Unfortunately the answer to that is ‘no’, because of the different types of controller between the standard and Pro items.
Note 2: Some companies continue to launch faster and faster Memory Stick products, resulting in additional nomenclature such as MS Extreme and MS Ultra – which are compatible with MS Pro devices.


XD Memory CardxD Picture Card (xD) - Legacy

xD (Picture) card slots are found in (older) Fuji and Olympus cameras, as the cards were developed by these companies. xD cards are often sold under license and therefore you may sometimes find a different brand on the packaging, but a Fuji or Olympus branded card inside. xD cards have a distinctive, shield style design and are roughly the size of your thumb. Storage capacity can be anything from 8Mb to 2GB.

Buy a 2GB Olympus xD Memory Card

There are three types of xD picture card available: Standard, Type M and Type H. The Standard cards have a maximum capacity of 512Mb but as higher resolution cameras have appeared, these cards simply don't cut the mustard.

In 2005, Fuji and Olympus released the first Type M card using Multi-level cell (MLC) technology to increase capacity and they can go upto 2GB, but these cards suffer from slow write speeds. Type H cards are a faster write speed than the Type M, and have the same maximum capacity as the Type H, but the speed is still not as fast as the original, smaller capacity cards.

The main problem with these cards is that they are not always compatible with older card readers or cameras and Olympus also have a Panoramic feature on their cameras which can only be recorded to Olympus cards. Olympus added the Type M+ to their range of xD picture cards. Type M+ is claimed to have a write speed 1.5x faster than regular Type M.

In 2009 Fujifilm stopped supporting XD card, switching instead to SD cards, and in 2010 Olympus followed suite and announced the switch to SD memory cards.

MicroDrive (MD) - IBM developed a miniature tape drive called the MicroDrive with the physical dimensions of a Compact Flash type II card. MicroDrives are comparatively rare and if your device supports the format it should say so explictely in your user manual. MicroDrives come in 170Mb, 340Mb and 1GB capacities.

Multi Media cards (MMC) - There often is some confusion around MMC cards as they have exactly the same physical format as SD cards. Many devices will support both formats – but not all. Despite some dealers telling customers not to worry when buying either card, please ensure that your device supports both types of card before you buy, or otherwise simply purchase the card it says it will.

Smart Media (SM) - Like CF cards, Smart Media cards are rather large, square but thin cards which, very distinctively, have a large gold ‘chip’ on the front. SmartMedia cards is no longer common and was used mainly in earlier digital cameras from Olympus and Fuji with capacities up to 128Mb.


Common Memory Card Questions (FAQ)

How do I get my photos off my camera and on to my computer?

If you're struggling to get your photos off your camera, for example, you might have lost the USB cable provided with you camera, then the easiest way to get photos on to your computer is using a USB memory card reader. Find out more in our complete guide to memory card readers.

Memory Card Speed

A common question is whether or not a camera or other device will support a certain speed, for instance a Class 10 card. Modern cameras should support all types of SD/SDHC/SDXC cards, however it is important to check that it supports the newest specification, such as SDXC, if it does not, then the card may not work. If the card has a faster speed rating than your camera will support, then it will fall back to the next speed that it does support, for example if your camera does not support UHS-I, then it will fall back to using Class 10. Therefore, if speed is of importance, you can safely buy the fastest card you wish to.

Card speed is often stated in ‘Times’ speed (20X, 66X etc.) and sometimes, more specifically, in Megabyte per second - reflecting the card’s per-second ability to have data transferred from or to it, with the write speed being the most important:

Speed Class Transfer Rate
8X   1.2 Mb/sec
12X   1.8 Mb/sec
20X Class 2 2.0 Mb/sec
25X   3.8 Mb/sec
30X Class 4 4.0 Mb/sec
40X Class 6 6.0 Mb/sec
60X   9.0 Mb/sec
66X Class 10 10.0 Mb/sec
80X   12.0 Mb/sec
133x   20.0 Mb/sec
266x   40.0 Mb/sec
300x   45.0 Mb/sec
  UHS-I upto 50 Mb/sec
  UHS-I upto 104Mb/sec
  UHS-II upto 312Mb/sec

Capacity - The following table illustrates commonly available capacities per card type. Please note that technology progresses so fast that larger capacities become available almost every few months, whilst smaller capacities become obsolete (e.g. 16Mb, 32Mb, 64Mb).

 X   X     X X X      
 X   X     X X X      
 X   X     X X X    X  
 X   X     X X X    X  
 X   X     X X X    X  X
 X X X     X X X    X  X
 X X X     X X X X  X  X
 X X X     X X X X  X  X
 X X X     X X X X  X  X
 X X   X       X X  X  X
 X X   X       X X  X  X
 16GB  X     X         X  X  
 32GB  X     X         X    
 64GB  X       X            
128GB  X       X            
256GB  X       X            
512GB  X                    

X Becoming obsolete, X Available today, X Most popular capacities

Approximate Number of Images per Capacity

Camera type File Size 32Mb 64Mb 128Mb 256Mb 512Mb 1GB 2GB 4GB 8GB 16GB
2mp 900Kb 35 71 142 284 568 1137 2275 4551 9102  18204
3mp 1.2Mb 26 53 106 213 426 853 1706 3413 6826  13652
4mp 2Mb 16 32 64 128 256 512 1024 2048 4096  8192
5mp 2.5Mb 12 25 51 102 204 409 819 1638 3276  6552
6mp 3.2Mb 10 20 40 80 160 320 640 1280 2560  5120
8mp 4Mb 8 16 32 64 128 256 512 1024 2048  4096
10mp 5.3Mb 6 12 25 51 102 204 409 819 1638  3276
12mp 5.7Mb 5 10 20 40 80 160 320 640 1280  2560
16mp 8Mb 4 8 16 32 64 128 256 512 1024 2048
20mp 10Mb 3 6 12 25 51 100 200 400 800 1600
24mp 12Mb 3 5 10 21 42 84 166 333 666 1333
36mp 20Mb 1 3 6 12 25 50 100 200 400 800

Note: 1GB = 1024MB

Layers - Finally a very short note on ‘layers’. As mentioned, memory cards contain ‘controllers’ – software that managed the storage and retrieval of data. The quality, capacity, speed, energy-efficiency and longevity of a memory card depends on its materials, and the architecture of its controller software. So called single-layer cards are usually more expensive but offer superior energy efficiency, longevity and speed than multi-layer cards.

Longevity - Apart from the fact that technology leads us to ever growing capacities and speeds and therefore sometimes rendering certain card sizes such as 16Mb or 32Mb obsolete, it is worthwhile to note that memory cards have a limited life expectancy. Again there is a difference; single layer cards may allow in excess of maybe 100,000 read-write actions, whilst multi-layer cards may only allow around 10,000 to 15,000.

This article was updated March 2019.

MPB Start Shopping

Support this site by making a Donation, purchasing Plus Membership, or shopping with one of our affiliates: Amazon UK, Amazon US, Amazon CA, ebay UK, MPB. It doesn't cost you anything extra when you use these links, but it does support the site, helping keep ePHOTOzine free to use, thank you.


Other articles you might find interesting...

Samsung Pro Endurance Memory Cards Introduced
Angelbird Introduces New AV PRO CFexpress Type B SE And SX M...
Samsung Introduces Fast and Durable PRO Plus and Enhanced EV...
Lexar Adds Professional CFexpress Type B Card Silver Series...
Lexar Introduce SD Express With Groundbreaking Speeds
Best Selling SD MicroSD Memory Cards
Lexar Introduces Professional 1066x SDXC UHS-I Memory Card S...
Kingston Digital Reveal New SD and microSD Memory Cards & Me...



kombizz 17 601 1 United States
Thank you for sharing this valuable info.
God Bless
chearse for this info very good i didnt know the diffrence between cf type 1 and 2!!!
Very useful article

Sign In

You must be a member to leave a comment.

ePHOTOzine, the web's friendliest photography community.

Join For Free

Upload photos, chat with photographers, win prizes and much more.