Markings On Micro Sd Cards
MicroSD cards are small, inexpensive memory units that people use for storing data in MP3 players, cameras and other devices, and for transferring files between devices and a computer. Standard SD cards can be made with a max capacity of up to 2GB. SDHC cards come in capacities ranging from “greater than 2GB” to 32GB. SDXC cards range from “greater than 32GB” to 2TB. At present, the 2TB limit is a max theoretical limit only, with most SDXC cards in the 64GB flavor.
In this guide, we’ll break down everything you need to know about Secure Digital (SD) memory cards for your smartphone, tablet or camera. Let’s go!
Form factor: SD vs Micro SD
There are two major form factors when it comes to memory cards: SD and micro SD. SD cards are generally used in larger devices, like cameras and video cameras; and are a little bit larger than a postage stamp. Meanwhile, Micro SD cards tend to be used in smartphones, tablets and other portable gadgets. They are much smaller than full-size SD cards, about the size of a fingernail.
There’s also a third form factor, Mini SD, but this was largely a transitional form factor used in the mid 2000s before Micro SD became popular. It is rarely seen today.
Families: SD vs SDHC vs SDXC
There are also different families or generations of SD cards: the first generation SD, the second generation SDHC, and the third general SDXC. In general, each new generation brought increased speeds and capacities, allowing faster and larger cards to be made.
The different families also use different filesystems – SDHC cards came with FAT32, and SDXC cards use the exFAT filesystem. Both FAT32 and exFAT are supported by recent versions of Windows and Mac, although Linux distributions often support only FAT32 for legal reasons.
Speed: Class 6 vs Class 10 vs U1 vs U3
Each SD or Micro SD card has a speed rating, called a class. Larger class numbers correspond to a faster level of minimum performance, allowing files to be copied or recorded at a higher speed.
The class rating system is actually quite simple to remember: the number after each Class corresponds to the minimum sequential read speeds, in MB/s. So Class 2 is 2MB/s, Class 6 is 6MB/s, etc. For example, Class 2 is sufficient for SD video recording, while 4 and 6 support HD recording. Class rating is shown on the card with a number inside a circle.
After Class 10, it gets a bit more complicated. An additional standard called UHS was introduced, which allows cards to reach higher speeds. Here we see a similar system – UHS Class 1 (or just U1), which corresponds to a minimum performance rating of 10MB/s, while UHS Class 3 corresponds to a performance rating of 30MB/s. UHS Class 3 supports 4K video recording. UHS speed classes are shown on the card with a number inside a U.
Confusingly, U1 and Class 10 refer to the same 10MB/s speed standard, so sometimes you’ll see cards that are labelled both as Class 10 and UHS-1.
Compatibility
Generally, host devices (e.g. cameras, mobile phones and card readers) work with older SD cards, but newer SD cards may not work in older devices. For example, the host device might not be able to read the full size of the card, read the file system of the card or just have a wrong hardware interface. Wikipedia has a nice list of factors and a table of compatibility, if you’d like more details.
Fairly obviously, form factors also impact compatibility. Full-size SD cards and Micro SD cards will not work in host devices designed for one another, although smaller cards can fit into larger card slots via adapters (see the section below).
Additionally, some older devices don’t support the UHS-1 standard, which may result in slower-than-expected performance when using U1 or U3 cards.
For these reasons, it’s important to search for manufacturer specifications for your device before buying an SD or Micro SD card. Usually, Googling for the name of your device plus “largest SD card” will work.
Adapters
Mini and Micro SD cards can be placed inside passive adapters, allowing them to be used in ports designed for larger form factors. Most commonly, Micro SD cards can be placed inside SD adapters. This is useful for using a single card in multiple devices (such as a phone and a digital camera), as well as using Micro SD cards in SD card readers (like those on laptops and desktop PCs).
Conclusion
We hope that this guide was useful. If you have any unanswered questions – or you just want to let us know that it helped – please get in touch via the comments below! You can also reach us on Twitter @mobilefun!
First image credit: Wikipedia.
Secure Digital (SD) cards are used in digital cameras, music players, smartphones, tablets, and even laptops. But not all SD cards are created equal—you’ll find different speed classes, physical sizes, and capacities to consider.
Some devices—like cameras—may require an SD card for their primary storage area. Other devices—like smartphones, tablets, and even computers—may offer the ability to use an SD card to increase storage or make it mobile. However, different devices require different types of SD cards. Here are the differences you’ll need to keep in mind when picking out the right SD card for your device.
Speed Class
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Not all SD cards offer the same speeds. This matters for some tasks more than others. For example, if you’re a professional photographer taking photos in rapid succession on a DSLR camera and saving them in high-resolution RAW format, you’ll want the fastest SD card you can get so your camera can save them as quickly as possible. A fast SD card is also important if you want to record high-resolution video and save it directly to the SD card. If you’re just taking a few photos on a typical consumer camera or using an SD card to store some media files on your smartphone, the speed isn’t as important.
Manufacturers use “speed classes” to measure an SD card’s speed. The SD Association that defines the SD card standard doesn’t actually define the exact speeds associated with these classes, but they do provide guidelines.
There are four different speed classes—10, 6, 4, and 2. Class 10 is the fastest, suitable for “full HD video recording” and “HD still consecutive recording.” Class 2 is the slowest, suitable for standard definition video recording. Classes 4 and 6 are both deemed suitable for high-definition video recording.
There are also two Ultra High Speed (UHS) speed classes–1 and 3—but they’re more expensive and are designed for professional use. UHS cards are designed for devices that support UHS.
Micro Sd Symbol Meanings
Here are the associated SD class speed logos, in order from slowest (class 2) to fastest (UHS class 3):
You’ll probably be okay with a class 4 or 6 card for typical use in a digital camera, smartphone, or tablet. Class 10 cards are ideal if you’re shooting high-resolution videos or RAW photos. Class 2 cards are a bit on the slow side these days, so you may want to avoid them for all but the cheapest digital cameras. Even a cheap smartphone can record HD video, after all.
An SD card’s speed class is identified on the SD card itself—just look for the logo. You’ll also see the speed class on the online store listing or on the card’s packaging when purchasing it. For example, in the below photo, the middle SD card is speed class 4, while the two other cards are speed class 6.
If you see no speed class symbol, you have a class 0 SD card. These cards were designed and produced before the speed class rating system was introduced. They may be slower than even a class 2 card.
Physical Size
SD cards also come in different sizes. You’ll find standard SD cards, miniSD cards, and microSD cards.
Standard SD cards are the largest, although they’re still pretty small. They measure 32x24x2.1 mm and weigh just two grams. Most consumer digital cameras for sale today still use standard SD cards. They have the familiar “cut corner” design.
miniSD cards are smaller than standard SD cards, measuring 21.5x20x1.4 mm and weighing about 0.8 grams. This is the least common size today. miniSD cards were designed to be especially small for mobile phones, but now that we have an even smaller size—microSD—miniSD cards aren’t too common.
microSD cards are the smallest size of SD card, measuring 15x11x1 mm and weighing just 0.25 grams. These cards are used in most cell phones and smartphones that support SD cards. They’re also used in many other devices, such as tablets.
Choosing a size is really just about what fits into the device you have. SD cards will only fit into matching slots. You can’t plug a microSD card into a standard SD card slot. However, you can purchase adapters that allow you to plug a smaller SD card into a larger SD card’s form and fit it into the appropriate slot. Below, you can see an adapter that lets you use a microSD card in a standard SD card slot.
Capacity
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Like USB flash drives, hard drives, solid-state drives, and other storage media, different SD cards can have different amounts of storage.
But the differences between SD card capacities don’t stop there. SD Standard Capacity (SDSC) cards range in size from 1 MB to 2 GB (and sometimes even 4 GB—although that’s not standard). The SD High Capacity (SDHC) standard was created later, and allows cards 2 GB to 32 GB in size. An even more recent standard, SD Extended Capacity (SDXC) that allows cards 32 GB to 2 TB in size.
Best Prices On Micro Sd Cards
To use an SDHC or SDXC card, you’ll need to make sure your device supports those standards. At this point, the vast majority of devices should support SDHC. In fact, the SD cards you have are probably SDHC cards. SDXC is newer and less common.
When buying an SD card, you’ll need to buy the right speed class, size, and capacity for your needs. Be sure to check what your device supports and consider what speed and capacity you’ll actually need.
Micro Sd Cards For Cell Phones
Image Credit: Ryosuke SEKIDO on Flickr, Clive Darra on Flickr, Steven Depolo on Flickr