The DJI Mini 3 uses microSD memory cards, and if you plan to do a lot of filming at 4K resolution, then you’re going to need a fast card with a lot of storage space.

Having a spare memory card or backup storage on your phone or controller is also really useful so that you still have some space in case you fill up your memory card or if the SD card fails. 

Sandisk Extreme Pro MicroSD cards are the most reliable cards I have used. They also have a high write speed, which you need for recording 4K footage at 100Mb/s. 

This is what we mean by a fast card – it needs to be able to keep up with the high video bit rate of the Mini 3.

What is an SD card?

An SD card is a type of flash memory card that uses a series of electronic logic components called NAND chips that allow data to be written and stored on the SD card. These chips allow the card to retain data without a power supply. 

Flash memory is becoming the memory of choice in budget computers and mobile devices.  Drones utilize this type of memory due to it being lightweight.

Other types of storage, such as magnetic storage devices, would be too bulky and heavy for use on drones.

SD cards come in different sizes, with microSD or TF cards being the form factor used with most consumer drones. 

Due to their size, microSD cards used to be more expensive and less capable than larger SD cards.

However, due to the popularity of the microSD form factor and the advances in storage density and performance, microSD cards are now almost on par with SD cards in regard to price and performance.

What do the numbers mean?

When searching for an SD card for your Mini 3, you’ll find a range of options from different brands, all with different numbers and letters.

Don’t panic – these numbers and letters are standardized parameters that help categorize these cards. 

The first number you’ll be interested in is the storage capacity.

Depending on how much filming you want to do and how often you want to download the footage and clear the SD card, then you’ll want to choose a card of at least 16 gigabytes (GB).

Any less than this, and you’ll have your SD card plugged into your computer for more time than you’re flying your Mini 3. 

I use 64GB cards, and the Mini 3 should be able to accept cards with storage of 256GB and above, provided they’re in the correct format.  DJI also lists a number of recommended SD cards for the Mini 3 on its website.

DJI’s recommended cards for the Mini 3 are:

Keep in mind that 1GB of storage equates to roughly 80 seconds of video at the Mini 3’s maximum bit rate, so you could fill up an SD card pretty quickly.

It is worth having an SD card with enough storage to allow you to film for the entire flight without having to land to change SD cards.

The next indicator to look for from the card is a small symbol which will either be one or a combination of a letter with a number.  These specify the speed class of the card. 

The minimum speed class you should be looking for is Class 10, denoted on most cards by the number 10 positioned inside the letter “C.” Class 10 indicates that the card has a minimum write speed of 10MB/s. 

Additionally, or alternatively, the card may have a number inside a “U” shaped symbol.  This denotes that the card has an Ultra High Speed (UHS) class, with U3 being the highest. U3 means that the card has a minimum write speed of 30MB/s. 

Finally, at the time of writing this article, an SD or microSD card may additionally or alternatively have a video write speed class, denoted by the letter “V” and a number.

V90 represents the highest video write speed class of microSD cards at present.  This means that the video write speed of the card is a minimum of 90MB/s.

Since the bit rate of the Mini 3 camera at 4K is 100Mb/s (megabits per second), then the minimum write speed for the microSD card you need will be at least 12.5MB/s (megabytes per second).

Most cards will also show a speed in MB/s on the label.  However, this is usually the read speed of the card, which is usually higher than the write speed. That’s why they put that number on the card – it makes it look faster.

For recording drone footage, the write speed is the important number. 

However, read speed helps when copying the recorded footage to your computer.

If the write speed is too low, then the Mini 3 will only film for a short time before the recording stops, or the Mini 3 will drop frames, and the video will have bits missing. 

Slow write speed can also cause video files to become corrupted, resulting in no usable footage.  A V30 card should give you continuous recording at 4K on the Mini 3, or at least until it runs out of storage.

Tips for managing SD cards

When choosing the right size SD card storage for you, the largest capacity card in your budget isn’t necessarily the best.

I find using multiple slightly smaller cards is beneficial because you can use one card for certain shots and another card for others. That way, if one card becomes corrupted or fails, then you haven’t lost all of your footage from that day. 

MicroSD cards are also really small, and whilst I’ve never had one eject from a drone, your card could escape from the SD card slot in a crash.  This can be prevented by putting a small piece of tape on the drone to cover the SD card slot.

As microSD cards are small, it is also worth keeping them either in your drone or in a box in your bag so that they don’t get misplaced.

You may also need an SD card reader. Some manufacturers sell microSD card readers with their cards.

Alternatively, you can download footage from the drone over a USB cable to your PC or to your phone using DJI’s quick transfer. 

If you’re editing photos and videos on a computer, then I would recommend acquiring a card reader, especially if you’re using multiple microSD cards.

SD card readers can also have their own read speed, so it is worth getting a USB 3.1 or higher card reader so that you get the best transfer speeds.

If you’re using your drone regularly, such as for commercial work, it would also be worthwhile replacing SD cards every so often.

The chips used in flash memory only have so many switching cycles, and if one of the switches fails, then the whole card could fail.

To avoid this happening, you can replace your old cards with new ones from time to time (probably over the course of a few years).

In summary, most V30-rated microSD cards of 32GB and above will be sufficient for use with your Mini 3.

These cards will easily allow you to shoot loads of high-resolution photos and will be able to keep up with the Mini 3’s high-bitrate video capture.

For best performance, Sandisk Extreme Pro microSD cards will work best, and these cards come in a variety of storage capacities to suit your setup and budget.

If you have the RC controller with your Mini 3, then you can also put a microSD card in that to record footage both on the drone, and in the controller, just in case things go horribly wrong.

If you’re still in doubt about which card is right for you and your Mini 3, then you can choose from the selection of DJI’s recommended cards for the Mini 3.

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