Memory cards for cameras

It’s been a long time since I wrote an article about camera accessories, right? Well, you just bought a new camera? Then, it’s time to find a memory card to save all your pictures. But that’s where it starts to get messy, because it’s often a real headache when you don’t know much about it! Between SD and CF cards, storage capacities, writing and reading speeds, speed classes, and much more, there is enough to tear your hair out! Don’t worry, I’ll explain everything you need to know about these little electronic elements, indispensable to photographers. I will teach you how to interpret the hieroglyphs on camera memory cards so you can choose the one that will be best suited to your needs. For those who want to go further, I invite you to read our article on another camera accessory we do love: camera lens filters. It details everything you need to know about these little accessories, very useful in many situations.

When digital technology appeared, almost every camera manufacturer had its own memory card format, so much so that you could easily get lost! Fortunately, over the years, manufacturers wanted to standardize their offers and propose now standard card formats. Today, the two types of memory cards most used in cameras are SD (Secure Digital) and CF (Compact Flash).

SD cards are the most compact (even if they tend to be closer to CF for the top of the range). They are found in entry or mid-range DSLR, bridges, compacts and mirrorless.

CF cards are characterized by their performance and their speed. The only problem is that they are bigger and therefore take up more space. Known to be more powerful than SD cards (even if the difference tends to reduce), they are mainly found in professional and high-end DSLR cameras.

CF cards were introduced in 1984. The CFast 2.0 standard allows a reading speed of 600 MB/s. Since 2011, the trio Nikon-Sandisk-Sony has marketed the XQD format, with better performance than CompactFlash. It allows for example a theoretical speed of up to 1 GB/s (for version 2.0), thanks to PCI Express buses. In practice, they are limited to 440 MB/s. This is where the CFexpress card comes into play, which will surely supplant the XQD card, especially as the manufacturers who have opted for XQD are adding compatibility with CFexpress, like the recent Z6/Z7! Indeed, the latest version of memory card (which dates from 2016) promises even higher performance: higher speeds, thanks to the PCIe interface (3.0) on multiple lines. The CFexpress, type B, has for example a transfer speed of up to 2 GB/s. And since 2019, we have seen two new formats arriving:

• type A: speed of 1 GB/s, thanks to a PCIe line;
• type C: speed of 4 GB/s, thanks to four PCIe lines.

Given their performance, the price of CFexpress (B) cards can amount to several hundred euros…

Anyway, that’s your camera which will determine the format of your card, meaning you will not have much choice. The manual of your camera or the manufacturer’s website will tell you which card format is suitable.

This is often the first element considered. But what is storage capacity? This is the volume of data that the memory card can contain. It is expressed in Gb (gigabytes). Basically, a 1 GB card will allow you to take about 100 photos of 10 MB. Well, it all depends on the number of millions of pixels of your camera (because the more megapixels you have, the heavier the pictures are), but also on the selected recording quality. The higher the storage capacity, the more data you can store (photos, videos). But there is a downside: indeed, the risk of losing all your data at once is also greater if you increase the number of photos saved on your card… Data storage includes several parameters:

• the number of files: photos, videos;
• their weight: your picture will be heavier if your camera has a sensor with more pixels;
• the recording quality of your files: the JPEG format requires less storage space than the RAW format;

To know which storage capacity to choose, ask yourself the following questions: how will I use my camera (daily, for a trip, or occasionally for my child’s show, for example)? Do I have the possibility of copying photos regularly or not? Do I prefer to have several medium capacity cards or only a large one? Also knowing that, depending on the manufacturer and the type of cards, some will be more reliable than others, but generally also more expensive.

After format and storage capacity of a memory card, let’s look at its writing speed. What is the writing speed? It is the capacity of a card to record a quantity of data in a certain lapse of time. It directly affects how fast the images are recorded on the card. The video and burst modes are therefore greatly affected by the writing speed. However, be careful because most cameras use their buffer, precisely to avoid limiting the burst because of a too-slow card. Moreover, if the cards’ speed really had an impact, the manufacturers would put recommendations for the card according to the burst you want, which is not the case. On the contrary, they always announce bursts according to the quality (RAW/JPEGS), but never according to the memory card.

On the memory cards, you will see the maximum speed noted in two ways:

• in Mb/s. For example: for a 60 Mb card, this means that it can write 60 Mb of data in 1 second;
• in “X”: knowing that 1 X = 0.15 Mb/s. You just have to make the conversion then.

In addition to its technical characteristics, the writing speed has an impact on the price of a card, since it can be multiplied by 3 depending on its speed.

The reading speed does not impact your shooting, since the reading speed is only the time it takes to copy your files to your computer. It will be more or less important according to the characteristics of the memory card of your camera but will also depend on the type of connection with the computer.

It is noted in the form of a number, followed by an “x”. Thus, a memory card marked 400x is equivalent to a speed of 60 MB/s in reading.

Another label is present on the memory cards: the speed class. It corresponds to the minimum speed of the card: whatever happens, you will not have a lower speed. The speed class is very important if you shoot videos. Indeed, since the recording flow is constant, it is necessary to have a good flow, hence the interest to ensure a minimum speed class. As you can see, for “classic” photography, the requirements are not the same, so it is essentially the writing speed that must be considered first.

There are 3 types of speed classes:

• Classic,
• UHS,
• Video.

The classic speed class is materialized by a number in a “C”. It can go from 2 to 10. A class 4 card corresponds for example to a minimum speed of 4 Mb/s.

More recent, the UHS (Ultra-High-Speed) classes propose a classification from 1 to 3: UHS-I indicates a minimum performance of 10 MB/s, UHS-III of 30 MB/s. In fact, this nomenclature indicates, depending on the bus used, the maximum amount of data entering and leaving the memory card. The capacity of the transfer bus is even more important as the number noted after the letters UHS is large. The UHS-II and UHS-III series require a second row of pins (connectors) on the card, given the higher bus capacities than UHS-I.

The latest standard is the V class (Video Speed Class), especially aimed for videographers! It goes from V10 (minimum writing speed of 10 MB/s) to V90 (90 MB/s). Concretely, here are the speed classes I advise you, according to the videos you want to shoot:

• standard video: C4 to C10 or V6 at least
• FULL HD video: C6 to C10 or V10/V30
• 4K video: C10, UHS-I, or V10 minimum
• 8K video: V60 or V90

As you can see, for a higher quality video than standard video, you will need at least a C10, USH-III/V30 card.

The choice of your memory card (especially the format) will be first determined by the camera in which you will insert it. Most cameras accept SD cards, whether they are DSLR or mirrorless cameras. The SD card is gradually supplanting the CF card (and other formats). Only microSD cards remain, most often dedicated to cell phones.

In SD cards, there are subclasses according to their capacity:

• SD: up to 2 GB;
• SDHC (SD High Capacity): between 4 and 32 GB;
• SDXC (SD Xtreme Capacity): up to 2 TB;
• SDUC (SD Ultra Capacity): up to 128 TB.

Be careful if you choose SDXC and SDUC cards, you’ll have to check that your camera is compatible with this format, even if it is most often the case for SDXC.

The file management system (i.e., the storage and organization inside the SD card) is also to be taken into account. The FAT16 system is used by SD cards, FAT32 by SDHC cards and exFAT by SDXC and SDUC. For the storage of 4K videos, you will have to opt for example for exFAT, FAT32 only recording files up to 4 GB.

To choose your SD card, read the manual of your camera first, it will give you several indications:

• the type of cards supported;
• the necessary writing and reading speeds;
• the maximum capacity supported.

Here are the details of the compatibility of SD cards / compatible devices:

• SD card: SD, SDHC, SDXC and SDUC compatible devices;
• SDHC card: SDHC, SDXC and SDUC compatible devices;
• SDXC card: SDXC and SDUC compatible devices;
• SDUC card: SDUC compatible devices only.

Regarding writing speeds: it goes without saying that it is useless to buy a card writing at 300 MB/s if your camera is unable to reach this speed. That said, the usage of your camera will guide you in your choice of card. If you want to shoot high-definition video, then you’ll rather choose a fast card.

SDUC cards are best suited for professional use or high-quality video, given the ever-increasing amount of content (4K, 8K, VR, etc.) to store.

As you have understood, you will not choose the same cards depending on your camera and the type of pictures or videos you want to shoot.

Here are some examples of cards that I do recommend, along with their technical characteristics, that you can of course find in other brands:

• for pictures with a bridge or compact camera, an entry-level card will be enough. The SanDisk Extreme Pro 32GB Class 10 U3 has an excellent price-performance ratio (expect to pay about 15 euros for this memory card) and a large storage capacity,
• if you shoot a lot, especially in raw, and then want a little more capacity and a shorter transfer time to the computer, opt for the 64GB version which has a higher transfer speed.
• to shoot 4K or 8K videos, the ideal will be to go at the top of the range, with for example the Lexar 2000x.

To go further, here are currently the best SD cards as well:

• SanDisk Extreme PRO SDXC memory card (Up to 170MB/s, UHS-I, Class 10, U3, V30) – Available from 32GB to 1TB of storage
• SanDisk Ultra SDHC memory card (up to 120 MB/s, class 10, UHS-I, V10) – Available from 32 GB to 256 GB storage (slower/less storage but cheaper)
• Lexar Professional 633x SDXC UHS-I card – Available from 32GB to 1TB of storage

The brands which will associate reliability and speed are without any doubt SanDisk and Lexar. They are the most known on the market. They offer a very wide range: from the beginner photographer with a small budget, to the professional (or almost!) who uses an DSLR and needs very powerful memory cards. The feedback from photographers in general (and mine in particular!) is unanimous concerning these manufacturers and their products.

There are also other brands, like Transcend or Kingston. But sincerely, you will be able to find everything you are looking for with the first 2 brands mentioned, and with a good quality-price ratio. However, Kingston is becoming more and more present and reliable. They have a good know-how as they also manufacture RAM for computers.

A piece of advice: avoid low-end, store-bought, or other brands that are not well known (or not at all). You may save a few bucks when you buy them, but you’ll soon be in trouble if your card doesn’t work properly or if you lose all your photos. You will regret not having invested a little more in the first place!

To read the files on your memory card, a card reader is necessary. This electronic device can be either internal or external. About the first ones, not all desktop computers have a card reader. Even on laptops, and in order to make them more compact, manufacturers sometimes tend to remove the card reader. For external readers, they simply connect to your computer terminal via a USB port. You can use your computer’s USB port if it suits you, especially in terms of speed. If this is not the case and if you want to invest in an external card reader, here are two USB3 models that guarantee the maximum transfer rate with most cards. I particularly recommend you:

• SanDisk Extreme PRO SD card reader: it is compatible with UHS-II cards and backwards compatible with UHS-I and non-UHS SD cards;
• Sandisk ImageMate Pro multi-format card reader: its main interest is that it can read many card formats (SD, micro-SD, CF, etc.).

A must-have accessory to safely carry your memory cards everywhere and protect them: the carrying case. This accessory must be:

• compact: to slip it easily into a bag;
• rigid and resistant: to protect it in case of shock;
• waterproof;
• adapted to receive CF and SD cards: even if it is not essential, you might need both, you never know!

I particularly recommend cases to carry hard drive/memory card (at the same time) or the JJC case, both having a very good reputation. Some cases even have slots for your camera’s batteries, which can also be interesting.

Memory cards are fragile, so you have to take care of them. They are particularly sensitive to water, but also to sun and dust. It is therefore necessary to store them in appropriate places (carrying cases) and to handle them with care (no greasy fingers on the electronic chip!). If your card ever gets wet, all hopes may not be lost. Wipe it gently with a soft cloth, then dry it in the open air (especially not under a heat source!). Wait at least one to two days before trying to read it, to make sure it is completely dry.

Another piece of advice: never remove your card from your camera (nor your battery, for that matter) before it is completely turned off (the power must not be cut off before the end of writing), at the risk of losing all your data. So be patient, just a few seconds!

Finally, one last piece of advice: it is better to have several small capacity cards, than only one with a lot of memory. Indeed, if for some reason you lose your data, misplace your card or damage it, only a part of your files will be lost, not all of them…

If you have accidentally deleted or lost photos or videos or if an error message appears, don’t panic: there are still ways to save your files. Don’t take any more pictures, remove the memory card from your device and use a data recovery software. Here are some of them that are quite interesting:

• Recuva ;
• ADRC Data Recovery Software Tools ;
• SoftPerfect File Recovery ;
• PC INSPECTOR File Recovery.

That’s it, we’ve been through everything about memory cards for cameras. You now know everything (or almost!) about speed classes, storage capacity, formats, etc. I’ve tried to be as clear and complete as I can and give you as much information as possible to help you make the right choice. Once you have understood the basics of a memory card, you will have understood everything! If you’re interested in photo accessories, I mention in this article all the accessories you need when you travel!

See you soon,

Sylvain