Buying a Memory Card – What You Need to Know

Today many digital cameras, mobile phones, tablets, laptops, portable media players and even video game consoles use memory cards (also called Flash Cards) for removable data storage. Most people are buying  a memory card based solely on storage capacity, but there is more to choosing a card than just the amount of data it can hold.

Memory cards have been around for more than twenty years. As you might expect, during that time they have gone throught some major changes.

Physical Size

The first cirteria you should look at is the physical size that your device can handle. This choice has gotten easier than ever before. In the beginning there were several different varieties of memory cards. Sony had their own type of memory called the memory stick. Olympus and others supported the XD-Card. Besides the different varietits of cards, over the years, the size of these cards shrunk and the capacities have increased greatly. Take a look at the progression of cards shown below. These go from a large compact flash card that could only hold 16 MB of data to a 4 GB SD card to a 32 GB Micro SD card.

memoryBuying a Memory Card

Now the battle over which type of card to use is over. Sony and Olympus have acquised and now almost every one is using the SD card.

SD Cards

SD cards come in two sizes. There are standard-size SD cards and microSD cards. There is also a miniSD card slightly bigger than the MicroSD card, but only a smattering of old devices use this size.

All SD cards are very small. Measuring just 32 x 24 x 2.1 mm and weighing in at just two grams, standard SD cards are the largest. This is the most popular size for most digital cameras today. They have the standard “cut corner”  design.
MicroSD cards are the very small, measuring 15 x 11 x 1 mm and weighing just 0.25 grams. These cards are used in most cell phones and tablets today.

In most cases, you can purchase a MicroSD card and if your device requires a standard size SD card, the Micro card can be put in a small adapter. In effect, this turns it into a Standard SC card.

Buying a Memory Card

Capacities

As you saw in the previous image, storage capacities have been increasing dramatically. The most popular SD cards today range from 4GB to 64 GB. With today’s technology they can go much higher. SD Cards currently can go as high as 2TB. If you are purchasing a large card, you will have to also make sure that your device can handle cards of that storage capacity. Most newer smartphones and many new tablets can accept cards up to 2TB.

Luckily, the prices of memory devices have come down. So you can usually purchase a card with some extra room for a small increase in price. But how much room is enough?

You have to consider what you will be using the card for. Since photos take up more storage space than music or documents, you might be able to gear the size card you need by how many photos it holds. Remember that the size of photo is dependent basically on the number of Megapixels that the photo is taken at. Many of todays newer devices are coming in at about 12 Megapixels. Lexar, a premier SD card manufacturer estimates that at 12 Megapixels, each photo has a file size of approximately 3.4 MB. At that size, a 4GB card will hold 800 photos. A 8GB card will hold 2,000. A 32GB card will hold 8,600. A 64GB card will hold 16,500 photos.

HD Videos can take a lot more space. Again, according to Lexar, a HD video taken at 1080p takes up a lot more space. A 4GB card will only give you 30 seconds of video. A 32 GB card will give you 4 minutes. A 64GB card will give you 7 minutes and 30 seconds. So while you may not need a memory card that can handle terabytes of information for photos, it may be exactly what you need for shooting HD video.

SDHC & SDXC

You may see the label SDHC on memory cards. SDHC stands for “High Capacity SD Memory Card”. This is a standard that was introduced by the SD Card Association in 2006. So this standard uses a newer capacity file system. The SDHC standard applies to cards 2GB to 32GB in size. Most cards today support this standard. SDXD is a more recent standard that allows cards 32GB to 2TB in size. So if your device says that it supports up to 2TB, it can handle SDXD cards.

Speed Class

One of the misunderstood specifications of SD cards is the speed class. While you may not have even thought about it, the speed of the card can make a big difference.

The SD Association that defines the SD card standard provide guidelines for the speed. There are four different speed classes: 2, 4, 6, and 10. Two is the slowest and 10 is the fastest. This is shown on the card or the packaging as the number with a broken circular logo around it. It looks like a number encased in a capital “C”. The numbers indicate the minimum serial data speed. For instance, a Class 2 card has a minimum serial data of 2MB per second.

The speed of the card matters more for some tasks than it does for others. For instance, if you take photos in rapid succession or save them in raw format, you will want your camera to be able to save them as quickly as possible. (If you use Raw format, you will also want to get a very large capacity card, as this format takes up much more space than JPEGs and other compressed formats).

Speed is also important if you want to record video. Class 2 is suitable for standard definition video recording. Classes 4 and 6 are suitable for high-definition video recording. Class 10 can handle full HD video recording.

There are also two Ultra High Speed (UHS) speed classes. UHS cards are shown by the numbers 1 or 3 inside a bold capital U. These cards are designed for devices that support UHS. Therefore they are more expensive and are designed for professional use.

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. The UHC 1 card at 10MB/s is designed for the full HD video and image recording. You should use a UHS 3 card at 30MB/s when recording video in 4K.

Just as a PC, the components will only operate at the fastest speed of the slowest element. So putting a Class 10 card in an old digital camera or other old device will most probably not produce Class 10 speeds.

Cards to Avoid

If your card has no Class coding, it may have been produced before Speed Classifications were implemented. So such a card would be quite slow. Class 2 cards are also fairly slow compared to others, so you may want to avoid them, as well.

When purchasing memory cards, I recommend sticking to a name brand like Lexar, SanDisk, and Kingston to assure quality control.

Wi-Fi Enabled Cards

These cards are pretty popular and they work well to transfer data. Just remember that you will need a good Wi-Fi connection for them to work. Also, these cards get their power from the camera battery, so you can expect them to use at least a little more battery power than regular SD cards.

Author: Sandy Berger

Sandy Berger, respected computer authority, journalist, media guest, speaker, and author, has more than three decades of experience as a computer and technology expert. Her eight books include: How to Have a Meaningful Relationship with Your Computer, Your Official Grown-up's Guide to AOL and the Internet, Cyber Savers –Tips & Tricks for Today’s Drowning Computer Users, Sandy Berger’s Great Age Guide to Better Living through Technology, Sandy Berger’s Great Age Guide to the Internet, Sandy Berger’s Great Age Guide to Gadgets & Gizmos, Sandy Berger’s Great Age Guide to Online Health & Wellness, and Sandy Berger’s Great Age Guide to Online Travel. Sandy’s newspaper column, magazine articles, feature stories, product reviews, and computer tips can be found at her website, Compu-KISS.

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