Photo by Markus Winkler on Unsplash

Memory cards might be the least glamorous part of any camera kit, but they're arguably one of the most important. Buy the wrong card and you could bottleneck your camera's performance, miss critical shots during a burst sequence, or worse — lose footage entirely. Buy the right one and it simply disappears into the background, doing exactly what it needs to do, every time.

Whether you're shopping for your first mirrorless camera, upgrading your professional kit, or trying to figure out what card actually works in your drone or action camera, this guide covers everything you need to know: the different card formats, what speed ratings actually mean, how to match a card to your camera and shooting style, and what to look for when buying in Australia. If you're still deciding on the right camera body for your needs, our complete 2026 camera buying guide is a great place to start.

Why Memory Card Choice Actually Matters

It's tempting to grab whatever's cheapest at the checkout, but memory cards have a real and measurable impact on how your camera performs. A few scenarios where the wrong card causes genuine problems:

• Burst shooting slows down or stops: Your camera's internal buffer fills up and can't write fast enough to the card. You press the shutter and nothing happens.
• Video recording cuts out: High-bitrate video — especially 4K, 6K, or 8K — requires a sustained write speed the card simply can't maintain. The camera throws an error and stops recording.
• Slow file transfers: A card with a poor read speed takes forever to offload images to your computer at the end of a shoot.
• Incompatibility: Some newer camera bodies require specific card formats or minimum speed classes that older or budget cards don't meet.

On the flip side, spending on a card that's far faster than your camera can use is also wasted money. This guide helps you find the right match.

Memory Card Formats Explained

Before you can choose a card, you need to know which format your camera actually accepts. These are not interchangeable — the slots are physically different sizes and use different interfaces.

SD Cards (SDSC, SDHC, SDXC)

The SD card family is the most common format in the world, found in entry-level DSLRs, mid-range mirrorless cameras, vlogging cameras, drones, and dashcams. The three generations refer to capacity tiers:

• SDSC (Standard Capacity): Up to 2GB — effectively obsolete.
• SDHC (High Capacity): 4GB to 32GB — still in circulation but being phased out for most modern use.
• SDXC (Extended Capacity): 64GB to 2TB — the current standard for most cameras.

Most modern cameras accept all three, but always check your camera manual. An older body that only specifies SDHC support may not properly format or recognise an SDXC card.

UHS-I vs UHS-II SD Cards

Within the SDXC format, there are two major bus standards that determine how fast data can move between the card and your camera:

• UHS-I: Maximum theoretical interface speed of 104 MB/s. Suitable for most stills photographers and video shooters up to 4K at moderate bitrates.
• UHS-II: Maximum theoretical speed of 312 MB/s. Required for high-end mirrorless cameras shooting high-bitrate video, fast burst sequences, or RAW video recording.

UHS-II cards have a second row of pins on the back. They work in UHS-I slots (backwards compatible), but at UHS-I speeds — so you'd be paying UHS-II prices without the UHS-II benefit. Check whether your camera body actually has a UHS-II slot before buying.

CFexpress Type A

CFexpress Type A is a small-format card used in select Sony cameras. Despite being only slightly larger than an SD card, it uses the PCIe/NVMe interface — the same technology found in fast computer SSDs — for dramatically higher speeds. Read speeds on current cards can exceed 800 MB/s, making them suitable for demanding video formats and ultra-fast burst shooting. Sony's higher-end Alpha mirrorless bodies commonly feature a dual slot that accepts either CFexpress Type A or UHS-II SD cards.

CFexpress Type B

CFexpress Type B is the larger format card used in professional Canon, Nikon, Panasonic, and some other pro-tier camera bodies. It's physically the same size as the older CFast 2.0 card but uses a completely different interface — they are not compatible. Type B cards offer very high sustained speeds, often exceeding 1700 MB/s read in current-generation cards, making them the go-to choice for cinema cameras and professional-grade bodies shooting RAW video or very high frame rate stills.

CFexpress Type C

A newer, less common format designed primarily for video-focused devices. Currently used in a small number of cinema cameras and recording devices. If your camera uses Type C, the manufacturer documentation will say so clearly.

CFast 2.0

A predecessor to CFexpress Type B using the SATA interface. Found in older professional Canon bodies and some cinema cameras. CFast 2.0 cards are still manufactured and available, but this format is being phased out in favour of CFexpress Type B. Do not confuse the two — the slots look similar but the cards are not interchangeable.

CompactFlash (CF)

The original professional standard, now legacy. Still used in older professional DSLRs and medium format cameras. If you're shooting with a camera that uses CF cards, you'll know — it's a chunky, robust format that served the industry well. Cards are still available, though the range is narrowing.

XQD

XQD was Nikon's preferred high-speed format for their professional DSLRs before the transition to CFexpress. Some Nikon bodies that originally shipped with XQD slots received firmware updates to also accept CFexpress Type B cards — worth checking if you own one of these bodies. XQD cards are still available but are a dead-end format.

microSD

The compact sibling of the SD family, microSD is used in action cameras, drones, 360-degree cameras, and some compact vlogging cameras. Speed ratings and capacity tiers mirror those of full-size SD — and a microSD card inserted into an SD adapter functions exactly like an SD card in most situations, though relying on an adapter for a camera's primary slot isn't ideal for professional work.

Understanding Memory Card Speed Ratings

Speed ratings are where memory card marketing becomes genuinely confusing. Cards often display multiple speed designations, and knowing what each one means helps you cut through the noise.

Read Speed vs Write Speed

Every speed rating is either a read speed or a write speed, and they are not the same thing:

• Read speed determines how fast data comes off the card — relevant when transferring files to your computer.
• Write speed determines how fast data goes onto the card — critical for in-camera recording performance.

Manufacturers love to advertise the higher read speed prominently. Always look for the write speed when evaluating a card for shooting use. If a card doesn't clearly state its write speed, treat that as a red flag.

Speed Class (Class 2, 4, 6, 10)

The original SD speed class system uses a number inside a circle (C2, C4, C6, C10) to indicate a minimum sustained write speed in MB/s. Class 10 (10 MB/s) was considered the minimum for Full HD video recording. This classification is effectively obsolete for modern cameras but you may still see it on budget cards.

UHS Speed Class (U1 and U3)

A more relevant classification for current cameras. The number appears inside a U-shaped symbol:

• U1: Minimum sustained write speed of 10 MB/s.
• U3: Minimum sustained write speed of 30 MB/s — the minimum generally recommended for 4K video recording.

Video Speed Class (V6, V10, V30, V60, V90)

The Video Speed Class system was introduced specifically to address video recording requirements and gives a minimum sustained write speed in MB/s. The number directly tells you the speed:

• V6: 6 MB/s — very basic.
• V10: 10 MB/s — Full HD.
• V30: 30 MB/s — minimum for most 4K recording.
• V60: 60 MB/s — 4K high bitrate, some 8K formats.
• V90: 90 MB/s — required for high-bitrate 8K and RAW video formats on professional bodies.

V90 is the top of the Video Speed Class hierarchy and is currently the benchmark for demanding professional video work. If you're shooting RAW video or high-frame-rate 4K in a professional camera, V90 is often a hard requirement, not a suggestion.

Application Performance Class (A1 and A2)

These ratings are primarily designed for microSD cards used in smartphones and computing devices — they measure random read/write performance for running applications. You'll see them on microSD cards used in action cameras and drones. For camera use, sequential write speed matters more than these ratings, but A2 cards do tend to offer better overall performance in action camera applications.

How to Match a Memory Card to Your Camera

The most important step in choosing a memory card is confirming what your specific camera body actually supports. Here's how to approach that by camera type.

Entry-Level and Mid-Range Mirrorless Cameras

Most entry-level and mid-range mirrorless cameras — the kind that make up the bulk of cameras sold to enthusiasts and emerging photographers — use a single SD card slot with UHS-I support. For these bodies, a quality UHS-I card rated at U3/V30 or higher covers the vast majority of shooting scenarios, including 4K video at standard bitrates. Spending on a UHS-II card for a UHS-I slot gives you no performance benefit whatsoever.

If you're shooting occasional bursts of JPEG files, U1 may technically be sufficient, but U3 cards have become affordable enough that there's little reason not to start there.

Advanced Mirrorless Cameras

Higher-tier mirrorless cameras — those aimed at enthusiasts and working photographers — often feature UHS-II SD slots, sometimes in a dual-card configuration. These bodies can write to the card much faster than a UHS-I card allows, so pairing them with UHS-II cards unlocks faster buffer clearing, more sustained burst sequences, and the ability to record high-bitrate video formats without errors.

Some advanced Sony Alpha bodies combine a CFexpress Type A slot with a UHS-II SD slot, giving you flexibility but requiring you to choose whether to invest in CFexpress Type A cards for the primary slot or use UHS-II SD across both. null

Professional Mirrorless and Cinema Cameras

Professional-tier bodies are increasingly standardising on CFexpress — either Type A (Sony) or Type B (Canon, Nikon, Panasonic, and others). These cameras often shoot internal RAW video, extremely high-frame-rate burst modes, or high-bitrate compressed video formats that demand sustained write speeds no SD card can match.

For these bodies, CFexpress cards rated at V90 and with strong sustained write speeds (not just peak write speeds) are worth the investment. Check reviews and independent speed tests for the specific card models you're considering — published peak speeds don't always reflect real-world sustained performance.

DSLRs

DSLRs vary widely by generation. Current professional Canon and Nikon DSLRs use CFexpress Type B or CFast 2.0. Mid-range DSLRs typically use SD cards, and the UHS bus support depends on the specific body. Older DSLRs may use CompactFlash. Your camera manual is the definitive source here.

Action Cameras

Action cameras — including GoPro, DJI action cameras, and similar devices — use microSD cards. For 4K recording at standard frame rates, a U3/V30 microSD is the baseline minimum. For 4K at higher frame rates, 5.3K, or any high-bitrate recording mode, look for V60-rated microSD cards. The manufacturer's official memory card recommendations are worth following closely here, as action cameras can be more sensitive to card compatibility than traditional cameras.

Drones

Most consumer and prosumer drones use microSD cards, with requirements varying significantly by drone model and the recording modes you're using. DJI drones in particular have specific recommended card lists in their documentation — a card that performs perfectly in one DJI drone may throw errors in another. Always check the manufacturer's compatibility list for your specific drone model.

Compact Cameras and Vlogging Cameras

Compact cameras and dedicated vlogging cameras typically use SD cards, with UHS-I support being most common. A V30-rated SD card is a safe general starting point. Some of the more capable compacts now support UHS-II, so checking the spec sheet is worthwhile if you're pushing the camera's video capabilities.

Capacity: How Much Storage Do You Actually Need?

Card capacity is partly a personal preference question and partly a practical one. Here's how to think about it.

File Size by Format

Your file sizes depend on what you're shooting and how:

• JPEG files from a modern high-megapixel camera typically range from 5MB to 25MB per image depending on resolution and compression settings.
• RAW files from current mirrorless cameras commonly run from 20MB to 60MB or more per file, with high-megapixel bodies producing especially large files.
• RAW + JPEG doubles your storage consumption per shot.
• 4K video at common bitrates (around 100 Mbps) consumes roughly 45GB per hour. High-bitrate internal RAW video can be dramatically larger.
• 8K video multiplies this further — internal 8K RAW can consume several hundred gigabytes per hour depending on the codec.

Choosing a Capacity

• 64GB: Suitable for casual photographers shooting JPEG or moderate RAW volumes, or short video sessions. A reasonable starting point, though it can fill quickly during intensive shoots.
• 128GB: A popular all-round size offering a good balance of cost and capacity for most photographers and videographers. Covers a full day of typical mixed shooting.
• 256GB: Worthwhile for heavy RAW shooters, event photographers, or anyone recording significant amounts of video. Reduces card-swapping during long shoots.
• 512GB and above: Best suited to video-heavy workflows, multi-day shoots without reliable offload opportunities, or high-megapixel cameras generating very large RAW files.

One Large Card or Multiple Smaller Ones?

This is a genuine debate in photography circles. A single large card reduces card-swapping inconvenience, but puts all your images at risk if that card fails or is lost. If you shoot while travelling — where card failure away from home is especially costly — our travel photography gear and planning guide covers backup strategies and kit choices for shooting on the road. Multiple smaller cards spread the risk — if something goes wrong with one card, you've only lost part of the shoot. Many professional photographers use a small-card strategy for exactly this reason, especially at once-in-a-lifetime events. Cameras with dual card slots that can simultaneously write to both cards solve this problem neatly.

Dual Card Slots and Backup Strategies

Many mid-range and professional camera bodies now offer two card slots. How you configure them depends on your priorities:

• Overflow/sequential: The camera fills the first card, then automatically continues to the second. Effectively doubles your capacity.
• Simultaneous backup: The camera writes every file to both cards at once. Your shoot is backed up in-camera. The best protection against card failure.
• Separate formats: Some photographers write RAW to one slot and JPEG to the other, keeping high-quality originals and quickly shareable versions without extra post-processing steps.
• Video/stills split: Some camera bodies allow you to direct video recording to one card and stills to another, which can be useful for managing workflow when shooting mixed content.

If you own a dual-slot camera and are shooting professionally or at events where reshooting isn't possible, simultaneous backup mode is the configuration most working photographers would recommend.

Brand Reliability and What to Look For

Memory card reliability is not something to gamble with. Established brands invest in quality control, error correction technology, and offer genuine warranties. Some of the most consistently well-regarded manufacturers include Sony, Lexar, SanDisk, ProGrade Digital, and Delkin Devices — all of which produce cards across multiple formats and speed tiers.

When buying memory cards in Australia, purchase from reputable retailers rather than marketplace third-party sellers. Counterfeit memory cards — cards that report a false capacity or speed to your camera but fail catastrophically under normal use — are a real problem on unofficial marketplace channels. Buying from authorised Australian retailers protects you from counterfeits and ensures genuine manufacturer warranty coverage that's actually enforceable here.

Memory Card Care and Handling

A quality memory card treated well will last for many thousands of write cycles. A few habits worth building:

• Always format in-camera, not on your computer. Formatting via your camera's menu creates the correct file structure for that specific camera. Formatting on a computer can create a structure the camera doesn't fully recognise.
• Format regularly. Don't just delete files — periodically do a full format. This maintains the card's performance and clears any fragmentation or file system issues.
• Never remove a card while the camera is writing. Most cameras have an indicator light showing active card access. Always wait for this to stop before ejecting.
• Use a case. The physical contacts on a card are vulnerable. Store cards in a case rather than loose in a bag pocket.
• Back up promptly. A card in the field is not a backup. Get files onto at least two separate storage locations as quickly as practical after each shoot.
• Don't fill a card to 100%. Keeping some headroom — even 10% free — can help with write performance and reduce stress on the card's management systems.

Card Readers and Transfer Speeds

Even the fastest memory card is only as quick as the reader you use to transfer files. If you're using a UHS-II or CFexpress card and connecting via an old USB 2.0 card reader, you're losing almost all the speed advantage you paid for.

For UHS-I cards, a USB 3.0 reader is perfectly adequate. For UHS-II cards, you'll want a reader specifically rated for UHS-II. For CFexpress cards, you need a CFexpress-specific reader — they cannot be read in SD card readers. Many CFexpress readers connect via USB 3.2 Gen 2 or Thunderbolt for maximum transfer speeds.

A quality card reader is a worthwhile investment for anyone who regularly needs to transfer large volumes of files quickly. It also reduces wear on your camera's card slot, since you're not repeatedly inserting and removing the card from the body.

Quick Reference: Choosing a Card by Use Case

Casual Photography and Travel

Format: SD (SDXC) | Speed: UHS-I, U3/V30 | Capacity: 64GB–128GB

If you're shooting travel photos, family events, or casual portraiture in JPEG or moderate RAW volumes on an entry-level or mid-range camera, a reliable UHS-I card at U3 or V30 speed in 64GB to 128GB is the sweet spot. It covers all your shooting needs and keeps the investment proportionate to the camera.

Enthusiast Photography and Hybrid Shooting

Format: SD (SDXC) UHS-II | Speed: V30–V60 | Capacity: 128GB–256GB

Enthusiast mirrorless cameras with UHS-II slots benefit from faster cards to keep up with faster burst rates and higher-bitrate video modes. A UHS-II card rated at V60 provides a meaningful performance boost over UHS-I in compatible bodies without crossing into CFexpress territory.

Professional Stills Photography

Format: SD UHS-II or CFexpress (Type A or B depending on body) | Speed: V60–V90 | Capacity: 128GB–512GB

Working photographers shooting events, weddings, sport, or commercial work need reliability and speed above all else. Choose cards with proven real-world sustained write speeds, stick to reputable brands, and buy from authorised retailers to avoid counterfeits. Dual-card backup strategy is strongly recommended.

4K Video Production

Format: SD UHS-II or CFexpress | Speed: V60 minimum, V90 preferred | Capacity: 256GB+

For serious video work, sustained write speed is everything. A card's peak speed means little if it can't maintain that speed across a sustained recording session. V60 is the practical minimum for high-bitrate 4K; V90 is worth the investment if your camera supports demanding internal formats.

RAW Video and Cinema Cameras

Format: CFexpress Type B or Type A | Speed: V90 | Capacity: 512GB+

Internal RAW video recording produces the largest files the camera world creates. If you're still deciding on a camera body suited to serious video production, our guide to choosing the best camera for video breaks down what to prioritise by project type. Only CFexpress at V90 spec can reliably handle these formats. Budget accordingly — fast, high-capacity CFexpress cards are an investment, but they're genuinely necessary for this application.

Action Cameras and Drones

Format: microSD | Speed: U3/V30 minimum, V60 for demanding modes | Capacity: 64GB–256GB

Check the manufacturer's compatibility list first — it genuinely matters with these devices. Use a reputable brand, buy from an authorised retailer, and go for V60 or better if you're pushing the device's highest recording modes.

Final Checklist Before You Buy

1. Confirm the format your camera accepts — check the manual, not just memory.
2. Confirm the bus type (UHS-I, UHS-II, CFexpress Type A or B) your camera's slot supports.
3. Choose the minimum speed rating required for your highest-demand use case — and go one tier higher if budget allows.
4. Choose capacity based on a realistic estimate of your shooting volume between offloads.
5. Buy from an authorised Australian retailer to ensure genuine product and real warranty coverage.
6. Check your card reader — make sure it's fast enough to take advantage of your new card.
7. Format the card in-camera before your first use.

Memory cards are one of those purchases that reward a small amount of research. For a broader look at what to prioritise when building out your kit, our beginner's guide to choosing camera accessories covers the essentials beyond the card slot. null Getting the format, speed class, and capacity right for your specific camera and workflow means you'll never be stuck watching a buffer wheel spin when you should be shooting — and you'll have the confidence that your files are being written reliably every time you press the shutter.