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Memory Cards Explained: How to Buy a Reliable SD Card for Video

SD Card for Video

What is a Memory Card?

Memory cards are small and flat (much like a paper card) digital data storage devices.

They’re much like a hard drive or flash (pen) drive. You can use them to store any electronic data accepted by a computer, This would include photos, documents, videos, games and so on.

Memory cards are removable storage devices. You can erase data from them and you can write and rewrite digital data in them.

You don’t need a separate power source to make a memory card work. It derives power from the device it’s attached to.

The main advantage of a memory card is its size. You can fit it into the smallest of portable devices like smartphones and get a decent amount of additional storage space.

Types of Memory Cards

The two popular memory cards in the market are the SD (Secure Digital)and CF (CompactFlash)cards.

SD Cards

SD cards are further divided into standard SD and micro SD cards.

microSD Cards

The microSD card is the smallest among flash memory cards. It made its debut in 2005 and is popularly used with smartphones, tablets and IP cameras, and miniature hidden cameras.

CF Cards

CF cards are mostly used in the pro-level DSLRs, broadcast and digital cinema cameras.

They’re more robust and score big on durability.

Some camera models work with both types of cards. For example, the Canon EOS 5D has one slot for SD and another for CF.

The advantage is once one card’s storage is used up, data is transferred to the other card. So, you don’t have to stop to change cards while shooting.

SD Memory Cards Rule

SD memory cards have found favor among consumers worldwide.
This has resulted in the SD standard owning 80% of the memory card market share.

The popularity of the SD memory card can be attributed to its ease of use and universal support among various devices.

This means you can use the same SD card with smartphones, tablets, drones, HDTVs and cameras and video cameras depending on the class rating and speed class as explained below.

This interoperability feature is one of the main reasons for SD standard popularity.

Devices that Support Memory Cards

Memory cards became popular in photography as a replacement for film.
Its use has been extended to video cameras and smartphones.

Today electronic devices like HDTV, DVD recorders and smartphones accept memory cards. They are also used in gaming devices like Nintendo Wii and printers.

Can You Use the Same Memory Card with Different Devices?

Generally, you can. Bear in mind, though, that each device has its own memory card requirement.

If you’re buying a set of equipment to work with each other, make sure they support the same type of memory card.

That said, if you have an old device that supports standard SD cards, it may not work with newer variants of SD cards like SDHC and SDXC.

Read and Write Speed

The read and write speeds of a memory card are the important factors you should take note of.

The read speed indicates how fast data can be transferred from the card to another storage medium (hard drive or flash drive) or be played back.

Write speed indicates how fast data can be stored to the card from the recording device (camera, camcorder).

How to Find Out the Speed of a Card

The speed of the card is indicated on the card itself. It comes with a digit and an x.

The way to calculate it to multiply the number by 0.15MB/s. So, if the card is 2000x, it’s 2000 x 0.15 = 300MB/s.

This is the read speed.

To get the write speed, you would have to look at the card’s class rating as shown below. It’s printed on the card. There’s a number with an incomplete circle (C) around it.

A Class 2 card has a write speed of 2MB/s

A Class 4 card has a write speed of 4MB/s

A Class 6 card has a write speed of 6MB/s

A Class 10 card has a write speed of 10MB/s

Each card class has different capacities as explained below.

  1. A Class 2 card is suitable for the recording of standard definition video
  2. A Class 4 card can be used for recording HD video
  3. A Class 6 card works for the recording of Full HD video (1080p).
  4. A Class 10 card can record Full HD video

SD Card Speed Class

The SD Association lays down the 3 main types of SD card speed classes. They are Speed Class – SD High Capacity (SDHC), UHS Speed Class -SD Extended Capacity (SDXC I) introduced in 2010 and Video Speed Class (SDXCII).

In June 2018, the SD Association announced the SD Ultra Capacity (SDUC) card. It is referred to as Express card, to differentiate it from the other cards.

SDHC Speed Class

SD speed class cards’ write speeds include 2MB/s, 4MB/s, 6MB/s and 10MB/s.

These cards can safely be used for shooting SD (Standard Definition) video.

UHS SDXC Speed Class

According to the SD Association, the UHS Speed Class (SDXC I) is divided into U1 and U3.

U1 and U3 can handle write speeds of 10MB/s and 30MB/respectively.

UHS Speed Class cards can safely be used for shooting Full HD videos.

UHS Speed Class cards are not compatible with non-SDXC devices.

V Class SDXC II (Video Speed Class) Rating Cards

Memory cards with V class ratings (SDXC II) cater to the shooting of 4K, 8K and 360-degree video shooting.

V Class cards can handle a large amount of data transfer per second. The number after V denotes the amount of data per second the card can handle.

  • V60 can handle 60MB/s and V30, 30MB/s.
  • V6, V10, V30 and V60 cards can support the shooting of 4K video.
  • For 8K video, only V60 and V90 cards can be used.

Memory Card Buying Tips

These tips will help ensure you buy choose an appropriate SD card for video.

Memory cards are not backward compatible with host devices. You can’t use a newer class SD card with a device meant to read an older class SD. For example, you use an SDXC memory card with a camera that reads only SDHC cards.

Check Your Device Manual for Card Type and Capacity

The best place to check what card best suits your video camera is your manual. The type of card and the maximum capacity it supports will be clearly stated there.

This is an example from the Panasonic HC-V180 camcorder.

If the maximum capacity started is 128GB, that’s the maximum capacity card you can buy. If you buy a card with a larger capacity say, 256GB, the maximum you’ll get is 128GB. You’ll be wasting the extra 128GB.

So, don’t run out and buy the biggest capacity SD card before checking your camcorder manual.

Buy Established Brands

Buy established brands like SanDisk, Kingston and such. Be wary of cards that promise large capacities for lower prices even if it’s from an established brand.

To ensure you have no problems with your SD card, buy from authorized distributors or online marketplaces.

SD Card for Video Ideas

Here are some of the best SD cards for video.

SanDisk 128GB Ultra SDXC UHS-I Memory Card

This is a Class 10 card that supports the shooting of Full HD (1920 x 1080) video.

If you have the 64 GB to 256 GB versions of the card, you can read speeds of up to 100MB/s.

For 32GB cards, it’s 90MB/s.

It comes with a 10-year manufacturer warranty.

This SD card for video recording scores big on reliability. It’s temperature-proof, waterproof, shockproof, and x-ray-proof.

Check out the SanDisk 128GB Ultra SDXC UHS-I Memory Card.


If you’re looking for a good SD card for 4K video, choose this Samsung micro SD card.

With this card, you can enjoy a write speed of 60MB/s and a read speed of 100MB/s.

This 128GB EVO Select can transfer a 3GB video to your computer in just 38 seconds.

For peace of mind, there’s a 4-proof protection system. This keeps your recordings safe against water, and airport X-ray machines, among others.

Store up to 6 hours of 4K UHD video and 20 hours of Full HD video in this card.

The card comes with an SD adapter which allows you to use it with most devices, especially camcorders.

Check out the Samsung EVO Select 128GB SD card for 4K video.

SanDisk 128GB Extreme SDXC UHS-I Card

With this SanDisk 128GB card, you can enjoy write speeds of up to 70MB/s. Read speeds go up to 150MB/s (for devices that support such speeds).

You can record uninterrupted video at a write speed of 30MB/s.

This means you can capture problem-free 4K UHD video (3840 x 2160) with this card.

The card can handle extreme weather, water and shocks.

The card comes with a lifetime limited manufacturer warranty.

Check out the SanDisk 128GB Extreme SDXC UHS-I Card.

Also, check out more SD cards for video recording.

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