Ever wonder what SD card is the best for your camera?  If so, you’re not alone.  In the past, the standard for digital cameras was the Compact Flash also known as the CF card but the improvements in Secure Digital or the SD card’s speed and capacity have instigated a change in the industry.  This article is designed to help you learn a little more about them and what you should know in order to pick the right card for your camera.

History:   First, a few basics about the card itself.  SD cards were first introduced in 1999 as a joint project between SanDisk, Panasonic and Toshiba. The design of the new SD card was in response to poorly performing MMC cards and there is no doubt they changed the digital landscape for the better.  The original SD card was about half the thickness of the current version and much slower.  Over the years since then, the SD card has increased in speed and decreased in cost.  Today each SD card, regardless of speed or capacity, is the same physical size and has the same distinctive cut corner design.  Each card weighs about two grams which is equivalent to the weight of a standard playing card and each card also has a physical switch to allow information stored on the card to be protected from erasure.

It is noteworthy that, regardless of the card type, speed or capacity, the quality of your images will be unaffected by the SD card you choose.  That factor will be determined by your camera specs, lens choice and experience as a photographer.  The main advantage between selecting one SD card over another for your camera will be in the number of pictures you can take and how fast you can take them.

Manual:   When in doubt, check your manual.  I suppose it should go without saying but your first and best method in determining which card type, capacity and speed are right for you lies in the pages of your owner’s manual.  Regardless of what other advice or information I give you in this article, unless you check your manual first you won’t know for certain which cards you should consider.  That leaves you with an expensive trial and error method to determine what cards will work. 

Types:   SD cards come in four standard types or families: SDSC or Secure Digital Standard Capacity (the original SD card), SDHC or Secure Digital High Capacity, SDXC or Secure Digital Extended Capacity, and UHC or Ultra High Capacity.  The only two that matter to most of us will be the SDHC and SDXC card types.  Each of these two types comes in both micro and standard sizes.  Most cameras will utilize the standard size cards while their smaller micro sized cousins are used in devices such as cell phones.

SDHC cards came out in 2006 and can be up to 32 Gb in capacity.  They are twice as fast as the original cards and will work in just about any camera.  SDXC cards came out in 2009 and can be up to 2 Tb in capacity. They are much faster than the SDHC cards and most modern day cameras will have no issue in using them.  Newer UHC cards have come out since but they are geared more toward high quality video systems and most camera systems made prior to 2012 are not compatible with them.

Speed:  The speed of an SD card is measured by its class.  The word “speed” in this instance stands for how fast information can be written to a card or transferred from it and the word “class” refers to a standard guideline for how quickly a card can accept or transfer data. This class is noted on the front of the card by a letter C with a number in the middle of it or by a U with a number in the middle of it for UHS cards.  The numbers in increasing speed order are 0 (or no rating shown), 2, 4, 6 and 10.  UHS-I and UHS-II are newer designations for the latest and fastest class of cards.  Suffice to say, the higher the class number, the faster the card will record images and the higher the price tag.  This means that, at least theoretically, you will be able to shoot more images in a burst because the card can write those images to the card more quickly. (Other factors that will affect this will be your camera buffer size and processor speed.) Generally speaking, go for a Class 10 card.  In a pinch, a Class 6 will work for most cameras shooting single images, not video, but I would not suggest anything slower.  It is very frustrating to miss an image because your card is recording data slower than your camera can take photos.  For myself, I won’t use anything less than a Class 10.

Capacity:   The capacity of a card is really a matter of personal preference.  I use a 32 Gb SDXC card and find it wonderful that I can shoot most trips with just one card in my camera.  This is a great relief for me knowing that I will be less likely to lose a card with all my most recent images on it.  SD cards are rather small and I have actually lost an entire day of shooting because I dropped a card somewhere on a trail.  Another issue that concerns people is the possibility of a card going bad. Some people like to use several smaller cards and swap them out as they fill them to try and avoid this problem.  I have had a card go bad on me so I can vouch this is indeed a possibility.  However, as I usually buy brand name, decent quality cards and because I download my images every night, I opt for not losing a card over focusing on the small chance that a card will stop working.  There are larger cards out there, however I have noticed that as a card gets larger there is a slight decrease in speed so I for that and the sake of cost, I would keep my card size at or below 64 Gb. 

Brand:   On the subject of brand names, stick to cards made by known manufacturer’s such as SanDisk, Lexar or Delkin.  (I especially like SanDisk’s Extreme series which are designed to work well in very cold or hot temperature situations.)  I feel these manufacturers in particular spend a great deal of time and effort to make sure their products are of the highest quality. Quality translates into a reliable card that will have a long life. Don’t sacrifice a card manufacturer’s quality control methods for a few dollars of savings.  This is a gamble that may cost you some images you don’t want to lose. Also, remember to format your cards in your camera before the first use and after downloading any images you have saved to your computer.  If you don’t format your card on a regular basis, over time your card may stop performing as well, may start exhibiting strange behaviors or may stop working all together.

Cost:   You will notice that I have saved this section for last.  Cost used to be an issue but with SD cards becoming more popular the price tag for them has come down significantly and is no longer a true hindrance. My first digital camera was a Canon 10d.  I remember spending $125 each for four 512 Mb cards on sale! That is $500 for an equivalent 2 Gb card now. I would have a hard time finding a 2 Gb card today but if I could I guarantee it would cost less than $10. Times have changed!  You can easily pick up a high-quality card with a minimum of 32 Gb for under $50.  Great sales are going on all the time and I would suggest focusing on the other desired attributes of your card and then checking around for the best price.

SD cards have come a long way since their beginning.  They have turned out to be one of the most useful memory devices in the industry today and have survived long after some of their predecessors have gone the way of the recycle bin.  Hopefully, this article will have helped clear up some of the issues surrounding the selection of a great card for your camera and you can go back to worrying about your next image and not where your camera will store it.  Happy shooting!