Does it matter what memory card I use for my camera?

The short answer is yes, it definitely matters what memory card you use with your camera. The memory card is a key component that determines how your camera performs and what features are available to you. Selecting the right memory card requires understanding factors like capacity, speed, compatibility, and reliability. We’ll explore all of these topics in detail below.

What memory cards are compatible with my camera?

The first consideration is compatibility – which memory card formats and types work with your specific camera model? Most current digital cameras use memory cards with one of the following formats:

  • SD (Secure Digital)
  • SDHC (Secure Digital High Capacity)
  • SDXC (Secure Digital eXtended Capacity)
  • microSD
  • CompactFlash (CF)
  • CFast
  • XQD

Within these formats, cards come in different sizes, speeds, and capacities. Check your camera manufacturer’s manual to see which formats, sizes, and capacities are supported. Many cameras work with multiple formats – for example SD, SDHC, and SDXC.

The physical size of the card also matters – common sizes are standard SD, miniSD, microSD, and CF. The camera needs to have the appropriately sized card slot. For adaptable storage, some cameras have dual card slots that allow a CF and an SD card, for example.


SD cards have become the most ubiquitous format used in digital cameras and other devices like phones and tablets. The original SD card format stores up to 2GB. SDHC extended the maximum capacity to 32GB. SDXC further increased this to a theoretical limit of 2TB. Different generations of SD cards also impact speeds.


CompactFlash (CF) cards were very common in older DSLR cameras, and some higher-end DSLRs still use CF cards. They range from Type 1 which are fatter to Type 2 which are thinner. There is also Microdrive CF which uses a hard drive. CF cards top out around 1TB currently on the high end.

CFast and XQD

CFast and XQD are newer formats designed for very high data rates required by high resolution, high frame rate video. Professional level and broadcast quality video cameras may utilize CFast or XQD. They are not commonly used in consumer level still photography cameras.

Capacity: How much storage do you need?

Camera memory card capacity determines how much data you can save on the card before needing to offload the images/videos and reformat the card. Capacity needs depend on your camera resolution, shooting style, and desired time between offloading. A few key factors:

  • Camera resolution – Higher megapixel cameras create larger files that take up more card space.
  • Shooting RAW vs JPEG – RAW files are significantly larger than JPEGs.
  • Video recording – Video requires massive amounts of storage compared to stills.
  • Burst mode shooting – Capturing rapid sequences of shots fills the card quicker.
  • Time between offloading – How many photos/videos can fit before offloading to a computer?

Most consumer-level mirrorless and DSLR cameras today have sensors in the 10 to 45 megapixel range. Here are some example image sizes:

Camera resolution JPEG image size (avg) RAW image size (avg)
10MP 3.5MB 15MB
20MP 7MB 30MB
30MP 10MB 45MB
45MP 15MB 70MB

As an example, if you shoot RAW with a 20MP camera, a 64GB card could hold around 2000 images. If you shoot mainly JPEG, that same 64GB card could hold over 9000 images!

For video, file sizes rapidly grow. Recording 4K video at 30fps, you might average 1GB per minute of footage. A 64GB card would run out of space after only an hour of recording in 4K.

In conclusion, base your minimum capacity needs on your camera resolution, whether you shoot JPEG or RAW, your desired time between offloading cards, and how much video you capture. Most photographers should look for memory card sizes from 16GB up to 256GB.

Memory card speed ratings

In addition to capacity, memory cards have speed ratings that indicate how quickly they can save data from your camera’s sensor. Faster cards allow your camera to capture images in rapid succession without slowdowns. There are two main ratings for memory card speeds:

  • Write speed – The maximum rate at which the card can receive and save data from the camera. Measured in megabytes per second (MB/s).
  • Bus speed – The interface data transfer rate between the card and camera. UHS-I and UHS-II are interface standards for SD cards.

Write speed classes

Memory card write speed classes are graded on a scale from 2 to 10:

  • Class 2 – Minimum 2MB/s write speed
  • Class 4 – Minimum 4MB/s
  • Class 6 – Minimum 6MB/s
  • Class 10 – Minimum 10MB/s
  • U1 – Minimum 10MB/s (Ultra High Speed 1)
  • U3 – Minimum 30MB/s (Ultra High Speed 3)

A Class 10, U1, or U3 card is recommended at a minimum for any HD video or moderate resolution still photography. However, the class ratings only indicate minimum speeds. The real-world write speeds of cards within the same class can still vary significantly.

Bus interface speeds

SD cards also have bus interfaces that transfer data between the memory card and camera. These ratings are more relevant than write speed classes at the high end:

  • UHS-I – 104MB/s maximum interface speed
  • UHS-II – 312MB/s interface speed
  • UHS-III – 624MB/s interface speed

High-end SD cards will specify max read and write speeds up to 160MB/s and beyond, but still use the UHS-I bus which caps out at 104MB/s. To take full advantage of the fastest SD cards, your camera needs UHS-II or UHS-III interface support.

Real-world card speeds

A memory card’s real-world performance can meet, exceed, or fall short of its speed rating. Speed is impacted by:

  • Camera’s memory interface – UHS-I vs UHS-II slot
  • Bus transmission overhead
  • Camera’s image processor and shutter speed
  • Shooting burst mode vs single shots

Bus transmission overhead and camera image processors can bottleneck maximum interface speeds. Memory cards may have extra “hidden” speed margin above the rated specs to compensate for this. You’ll see significantly faster performance using a 95MB/s UHS-I card in a UHS-II camera than a 95MB/s UHS-I card in a UHS-I camera, for example.

When shopping for the fastest memory card, real-world read and write speeds are as important as interface ratings. User benchmarks help identify the fastest cards for your particular camera model and shooting style.

Card reliability and durability

A memory card’s reliability and durability are crucial. A card failure could result in irretrievable data loss or camera downtime at a key moment. Here are factors to consider for card reliability:

  • Reputable brand – Stick with major brands known for quality.
  • Vibration and shock rating – Cards rated to survive drops and vibration.
  • Temperature range – Industrial cards handle extreme cold/heat.
  • Error correction – Cards with ECC and wear leveling for long life.
  • Warranty – Look for a solid manufacturer warranty.

Higher end cards marketed for professional use offer enhanced durability ratings and longer warranties. You’ll pay more for pro-level reliability, but the cost of a card failure is high.

When to replace a memory card

With good care, today’s memory cards can last for years of use. However, there are signs indicating a card should be retired and replaced:

  • Slow performance – Long write times and buffer errors.
  • Frequent corruption – Images and video files corrupted.
  • Bad sectors – Card stops working, marked bad sectors.
  • Old age – More than 2-3 years old with heavy usage.

Replacing cards as a precaution every few years helps avoid failures at inopportune moments. Keep the old cards as backup until confirming the data transfers successfully to a new card.

Tips for memory card care

To maximize the lifetime and performance of memory cards, keep these tips in mind:

  • Handle carefully – Don’t bend, drop, or expose cards to major shocks.
  • Store safely – Keep cards in protective cases away from moisture and dust.
  • Use the right slot – Don’t force a card into the wrong slot.
  • Don’t overwrite – Erase cards before reusing, don’t just delete some files.
  • Offload regularly – Transfer images off the card to make space.
  • Format the card – Use in-camera formatting, not a computer.

Avoiding mishandling of the cards and Practice good file management will help your memory cards survive drops, vibration, extreme temperatures, and years of reliable service.


Getting the right memory card for your camera is about more than just capacity. Understanding card formats, speeds, durability, and proper care leads to selecting memory cards that perform reliably under your shooting conditions. Research which card specifications are required for your camera features and shooting style. Investing in high quality cards from reputable brands is worthwhile for serious photographers and videographers who depend on their cameras.