Monday, June 6, 2016

SD Memory cards are not all created equal

Most consumers don’t know that there are differences between memory cards besides the obvious capacities and different formats that are available. There are several identifiers to know to help you choose the right memory card for the type of shooting that you do and that can be crucial since not all cards are created equally. Before going out and buying new cards on sale…

1. Consider what type of photography do you do?

If you’re an action and sports photographer or even a videographer, having a memory card with a fast minimum write speed will be necessary in order to not miss those key frames in continuous modes or dropped frames in video. Many portrait shooters only shoot in continuous mode a handful of times, so depending on how you shoot, you might want a card with a fast minimum write speed to keep up with what your camera puts out. Continuous modes fill up the buffer that is in the camera, and if your camera can’t write the data from the buffer to the card fast enough, you’ll find a dramatic decrease in speed.

What format do you shoot in?

While I do recommend shooting in RAW, the main caveat is that they take up a lot more space compared to JPEG. If you’re a RAW shooter, your camera will be transferring more information to the memory card than those shooting with JPEG, and that speed delay may really slow things down– especially if you’re shooting in a continuous mode. If you’re shooting video, then the format, frame rates and bitrate will also be a factor when choosing speeds, as higher quality video really requires a faster consistent transfer rates to eliminate chances of quality issues or even stopping.

2. Find a card that meets your needs

VPG rating for CF(Compact Flash) cards stands for Video Performance Guarantee and is a specification from the CompactFlash 3.5 standard that is found on higher-end CF cards. 

This is a minimum guaranteed speed specification for writing continuous data streams from applications. The VPG specification is designed for very high-end HD video recording (in Pro DSLR and Pro Camcorders). There are currently two different ratings for the VPG standard, one being VPG 20 and the other being VPG 65. The 20 stands for 20MB/s and the 65 stands for 65MB/s. You’ll find them as little clapper board icons with the aforementioned numbers in it.

CF cards typically are faster and more durable than SD cards in my opinion, and they’re typically not as confusing. If you’re shooting stills, I’m sure you’ll be fine with any new card that has one of these icons on it.

Speed Classes for SD Cards

Speed Classes were created by the SD Association consist of two different clases with different markings within each class to help consumers know the minimum writing speed of the card. There technically are two different classes, one being UHS Speed Class and the other being Speed Class. The fastest at the time of this article is the UHS Class 3 mark with a minimum of 30MB/s followed by the UHS Class 1 mark at 10MB/s. Notices that the UHS Speed Class I and the Class 10 minimum write speeds are the same. This does not reflect maximum write speed or read speed.

3. Don’t get confused

In general, higher classes and larger numbers on newer cards will perform better. You’ll find that many memory cards go on sale right before a company releases a new line of cards and they may change the labels– or perhaps not! Date of release is important, so do your research if you’re planning to invest in some high speed cards.

This is where I say that not all cards are created equal. Study the memory cards above. All these cards were purchased at different dates. The branding will always vary and be confusingly inconsistent, but the consistency is found in the markings from the SD Association.

Notice that 2 of the pictured cards are Class 10 — the one on the far left, and the one in the middle, and then the MicroSD card on the right is UHS-I Class 1. They all guarantee at least 10/MBs minimum write speed which is good for the majority of people.

The newest cards of the bunch are the Extreme Pro 32GB UHS-II Class 3 SD card and the Extreme Plus 64GB UHS-I Class I MicroSD card, followed by the Extreme 16GB Class 10 SD card and the Ultra 32GB Class 10 SD Card, then the PNY Class 4 SD Card.

Ready to get confused? Check out these two memory cards, and you tell me the difference. SanDisk’s Extreme Pro line is their top tier, followed by Extreme Plus then Extreme. Tell me what you think about these two cards. Don’t let the branding and marketing fool you.

*See the 95 MB/s and the 90 MB/s? Those are company’s rated read speeds, the numbers that most consumers think as the most important. For more information about MB/s and X-Rated read speeds, read this.

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