Tutorials |What are memory card class ratings: Lexar answers photographers’ questions

HOW TO... What are memory card class ratings: Lexar answers photographers’ questions

Lear microSD cards now ‘work with GoPro’

Lexar is one of the market leaders in memory cards for all manner of devices. Recently we caught up with Joel Boquiren, Senior Product Marketing Manager at Lexar, who answered some of the common questions we hear from photographers about memory cards, such as what are memory card class ratings, what is the difference between SD vs SDHC vs SDXC cards and many more.

How can photographers buying a memory card find out how many images will fit on a card?

The capacity chart is available on our website that shows how many pictures can each capacity hold. This chart is based on a certain image file size.  So, depending on the resolution of the image captured the file size will vary.

What do the different memory card Class numbers indicate for those who aren’t familiar?

This is the SD speed class rating that indicates the speed of the card. These ratings are based on a minimum sustained data writing speed. The speed class is important for video mode or camcorders, where the device is actually saving a steady stream of data.

The resolution and format of the video indicates the amount of steady stream data. This translates to a minimum speed you need to guarantee that the video captured on the cards is recorded at an even, sustained rate with no dropped frames (in other words, preventing any lost data and choppy playback).

What difference will photographers notice between using 1 speed class over another?

Lower speed class such as Class 4 or 6 card are typical use in a digital camera, smartphone, or tablet. Class 10, U1 and U3 cards are ideal if you’re shooting high-resolution videos, high-quality images, and capture 4K video. This speed class rating messages the minimum sustained video recording speed of the card.  Best results would be to match the SD card speed rating with that of the camera’s supported speed rating.

Is this difference only noticeable if you have the latest camera? Or when you transfer files to your computer? Do you need USB C or USB 3 to see the impact or will USB 2 reveal the difference?

The video speed class is important when capturing/recording video with your camera (in-camera performance).  So, the higher this video speed class (MB/s) the better, provided your camera has the capability to match the card performance. The transfer performance is what the industry normally refer to as “read” speed.  This speed tells you how quickly you can transfer data from card to computer.

However, the max bus speed of the computer’s SD/microSD card slot will determine the maximum limit.  So if you have an SD card reader attached to a computer via the USB port and the computer supports only USB 2.0 speed, then that’s the max transfer speed your card will be limited to.

How long will your digital photos last?

What is the difference between SD vs SDHC vs SDXC cards?

Since higher capacities have grown, so have the SD cards. Standard SD cards are any capacity up to 2GB. SDHC is SD High Capacities which usually comes in at 4GB – 32GB. SDXC is SD Xtended Capacity and comes in capacities of 32GB and higher, with a theoretical maximum of 2TB.

For the uninitiated, what is the difference between write vs read speed?

Read/Write are a measure of performance on a storage device. Read speed determines how fast the photo can transfer from the computer to the card.

Write speed is the opposite, it determines how fast a photo can be written to the memory card. The faster the card, the more continuous shots you can take.  The write speed is important for burst mode shooting; the higher the better.  Again, best to match the card’s performance to the camera’s best capability

A lot of new photographers often ask if some memory cards are better for different types of photography?

Lexar has one of the broadest ranges of products for the imaging segment in the industry that can support everyday photographers to professional photographers.  Lexar work closely with the leading host manufacturers and align their new technology and new features as they come to market to ensure we provide best performance.

So, depending on the use case model, the type of card performance needed will vary.  For example, if you want to capture 4K video and fast action motion, then best to invest in a high-performance card with U3 video speed rating and fast write performance.

Selecting the right memory card for your GoPro

CF cards used to favoured because of their speed and they have a heatsink. SD cards have the benefit of size but no heatsink – so how do they deal with heat?

This picture has changed in the past few years.  The SD cards now support UHS-II speeds up to 312MB/s theoretically.  Lexar’s UHS-II cards have read/write speeds of 300/260 MB/s respectively.  There is a new UHS-III specification that will allow SD cards to double that performance in the future. CF cards highest spec was for UDMA-7 cards which had maximum speeds at 167MB/s.

We’ve seen most cameras switch to using SD-type cards, but there are others like XQD & CFast as well as MicroSD. What’s the future for card formats?

Lexar has been a leader in the digital imaging segment and we continue to work closely with the leading host manufacturers and align their new technology and new features as they come to market.

The higher performance cards like XQD & CFast are being adopted by the highly demanding broadcast and cinematography market and at the higher photography segments.   These formats provide much higher speeds than what SD offer today with UHS-II.

Lexar’s CFast cards has read/write speeds up to 525/445MB/s read/write, while the XQD card speeds up to 440/400 MB/s read/write.  With some newer cameras adopting these card formats, the professionals can take full advantage of the camera’s capability with these new cards.

For the majority of users, the SD and microSD card format meets many of their needs.  Remember, the SD card specs today still perform very high with cards in the market offering close to 300MB/s speeds.  There are some cameras that support UHS-II that can take advantage of these speeds.

What is the life span of a memory card?

Per SD Association, it states that a memory card lifespan depends on how it is manufactured. They say that the current technology along with normal usage, typically gives the card a lifespan of 10 years or more. Lexar offer limited lifetime warranty on our SD cards, 300X and up, and 5-year to limited lifetime warranty on our micro SD cards.

Finally, some manufacturers claim their SD cards are waterproof etc, but isn’t that true of all SD cards?

Lexar can’t speak for other manufacturers, but Lexar memory cards are water-proof and offer limited lifetime warranty on our SD cards, 300X and up, and 5-year to limited lifetime warranty on our micro SD cards.

Not all cards are built the same.  To claim waterproof messaging, one has to ensure that the products go through additional testing to ensure this.

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