Understanding SD Cards:
A Guide for New Photographers
Read speeds, write speeds, speed classes, capacity, everything you need to know before you buy.
Your camera is only as good as the memory card inside it. Buy the wrong SD card and you risk corrupted files, dropped frames, and buffering mid-shoot. This guide explains SD card specs in plain English and recommends four Integral cards from Carlos.gi covering beginner to enthusiast.
Read Speed vs Write Speed
The most misunderstood numbers on SD card packaging
Every SD card has two speed ratings: read speed (how fast data comes OFF the card) and write speed (how fast data goes ON). Write speed affects your shooting. Read speed affects your editing workflow.
Read speed is how quickly your computer or card reader can transfer photos and videos from the SD card. A faster read speed means your files copy to your computer more quickly after a shoot.
At 100MB/s, a 10GB folder of RAW files copies in about 100 seconds. At 180MB/s, the same folder copies in about 55 seconds.
Write speed is how quickly your camera can save photos and video to the card while you are shooting. This is the number that matters most for photographers. A slow write speed causes your camera to buffer and freeze mid-shoot.
Shooting 4K video requires at least 60–90MB/s write speed. Burst shooting RAW photos requires 45MB/s or more to avoid the camera pausing.
Write speed affects your shooting. Read speed affects your editing workflow. When choosing a card for photography, always check the write speed first. Manufacturers often advertise the read speed in large print because it is always higher, the write speed is usually in smaller text or not shown at all.
Speed Classes: What the Labels Mean
Class 10, U1, U3, V30 - decoded
SD cards carry standardised speed class ratings (Class 10, U1, U3, V30) that guarantee minimum write speeds. For most photographers in 2026, look for U3 + V30 as a minimum.
| Label | Min Write Speed | Good For | Avoid For |
|---|---|---|---|
| Class 10 | 10 MB/s | Basic photos, Full HD video | 4K video, burst RAW |
| UHS-I U1 | 10 MB/s | JPEG photos, 1080p video | 4K video, RAW burst |
| UHS-I U3 | 30 MB/s | 4K video, RAW burst shooting | Nothing - good all-rounder |
| V30 | 30 MB/s | 4K video, sustained recording | Nothing - recommended minimum |
| V60 | 60 MB/s | 8K video, high-speed burst RAW | Overkill for most photographers |
For most photographers in 2026, look for U3 + V30 as a minimum. This combination guarantees a 30MB/s minimum write speed, which handles 4K video and burst RAW shooting comfortably. All four cards in this guide meet or exceed this standard.
How Much Capacity Do You Need?
The right size depends on how you shoot
Capacity is measured in gigabytes (GB). For beginners, a single larger card is simpler. Professionals often prefer multiple smaller cards to avoid losing an entire day's work if one fails.
Holds approximately 800–1,200 JPEGs or 300–500 RAW files. Enough for a day trip or casual shooting session. Good for beginners who are still learning.
Holds approximately 3,000–5,000 JPEGs or 1,200–2,000 RAW files. The sweet spot for most photographers, enough for a full day's shooting without worrying about space.
Holds approximately 6,000–10,000 JPEGs, 2,500–4,000 RAW files, or 2–4 hours of 4K video. Ideal for travel, events, and anyone shooting video regularly.
For wedding photographers, videographers, and professionals who shoot all day without stopping. Also useful for long trips where you cannot offload files regularly.
All Cards Compared
| Card | Capacity | Read | Write | Class | Price | Score |
|---|---|---|---|---|---|---|
|
Integral UltimaPro 32GB Best Budget |
32GB | 80 MB/s | ~20 MB/s | C10 / U1 | £19 | 82% |
|
Integral High Speed 128GB Best All-Rounder |
128GB | 100 MB/s | 45 MB/s | U3 / V30 | £33 | 90% |
|
Integral PRO 256GB 180MB/s Best Enthusiast |
256GB | 180 MB/s | 130 MB/s | U3 / V30 | £55 | 93% |
|
Integral Momentum I 256GB Best Performance |
256GB | 210 MB/s | ~100 MB/s | U3 / V30 | £55 | 95% |
Integral UltimaPro 32GB
Class 10 / UHS-I U1 · 80MB/s Read · SDHC
The Integral UltimaPro 32GB is the ideal first SD card for a new photographer. At £26, it offers reliable performance for JPEG shooting and Full HD video. The U1 speed class means it is not designed for 4K video or burst RAW shooting, but it will handle everything a beginner camera throws at it.
Integral High Speed 128GB
UHS-I U3 / V30 · 100MB/s Read · 45MB/s Write · SDXC
The Integral High Speed 128GB is our top recommendation for most photographers. The combination of 100MB/s read, 45MB/s write, U3/V30 rating, and 128GB capacity covers virtually every shooting scenario. The V30 rating guarantees smooth 4K video recording, and the 45MB/s write speed handles burst RAW shooting without buffering. At £45, it represents outstanding value.
Want the best all-round card for the money. Shoots RAW, handles 4K, and has enough space for a full day out.
Shoot sustained 4K at high bitrates, need faster transfer speeds, or shoot events where 128GB is not enough.
Integral PRO 256GB 180MB/s
UHS-I U3 / V30 · 180MB/s Read · 130MB/s Write · SDXC
The Integral PRO 256GB is a serious card for serious photographers. The 130MB/s write speed is nearly three times faster than the 128GB card above, making a tangible difference when shooting sustained burst RAW sequences or high-bitrate 4K video. At 256GB, you have enough space for a full wedding, a day of wildlife photography, or several hours of 4K video.
Integral Momentum I 256GB
UHS-I U3 / V30 · 210MB/s Read · SDXC
The Integral Momentum I is the fastest SD card in this guide, with a 210MB/s read speed that is genuinely impressive. This is the card for photographers who regularly transfer large volumes of files and want the fastest possible workflow. Particularly well-suited to high-resolution cameras (45MP+) where file sizes are large and transfer time adds up quickly.
Which SD Card Should You Buy?
"For most photographers, the Integral High Speed 128GB at £45 is the right answer. It handles everything from JPEG to 4K video, has enough space for a full day's shooting, and costs less than a dinner out."
| Rank | Card | Best For | Score |
|---|---|---|---|
| 1st | Integral Momentum I 256GB | High-res cameras, fast workflow | 95% |
| 2nd | Integral PRO 256GB 180MB/s | Burst RAW, 4K video, events | 93% |
| 3rd ★ | Integral High Speed 128GB | Most photographers - best value | 90% |
| 4th | Integral UltimaPro 32GB | Beginners, budget, backup card | 82% |
Get the Right Card for Your Camera
All Integral SD cards available at Carlos.gi in Gibraltar. Free local delivery. Expert advice from our team.
