SD cards for cameras: how to choose the right capacity and speed for you ?

Choosing a memory card for your camera might seem like a trivial matter. And yet, this is often where a lot depends on the right choice. A card that’s too slow, and your burst shots will stop at the worst possible moment. Choose the wrong capacity, and you’ll run out of storage space in the middle of a shoot. Not to mention the technical markings printed on the cards, Class 10, UHS, V30, which remain a real headache for many photographers.

So how do you make sense of it all? We’ll break it all down together, step by step, so you can choose a memory card with the confidence that you’re making the right choice, based on your camera and your shooting style.

Class 10, UHS, V30… Decoding your SD card’s markings without getting lost

On an SD card, the markings pile up. Numbers, letters, symbols. At first glance, it all looks like technical jargon reserved for insiders. In reality, each marking answers a specific question. You just need to know which one.

Which SD card speed should you choose?

It all depends on what you’re photographing. For everyday photography, portraits, landscapes, travel, a Class 10 card is more than sufficient. It guarantees a minimum write speed of 10 MB/s, which covers the vast majority of everyday uses.

As soon as you switch to burst mode or video, the requirements increase. You’ll then need to look at UHS cards, with a U1 or U3 rating. For example, U3 ensures a minimum write speed of 30 MB/s, a threshold necessary for continuous shooting without the camera pausing.

The V class also comes into play for video. V30 means a guaranteed 30 MB/s continuous write speed, whilst V60 and V90 go even further for very large file formats. For the majority of amateur or semi-professional photographers and videographers, the V30 offers a very good balance.

How do you choose the speed of your SD card?

The best way to choose is to base your decision on your actual usage, not the maximum specifications advertised on the packaging. A manufacturer may advertise an impressive read speed, but it’s the write speed that really matters for a camera.

Here’s a simple way to think about it. If you’re shooting in JPEG, a U1 or Class 10 card will do the job. If you’re shooting in RAW, go for a U3. If you’re filming in 4K, the V30 becomes essential. And if your device supports UHS-II, a compatible card will allow you to fully utilise its transfer capabilities.

The AgfaPhoto SDHC 32 GB Class 10 SD card, for example, meets the needs of photographers who work mainly in JPEG or light RAW, with proven reliability in everyday use.

What is the write speed of a camera SD card?

This is the question many people forget to ask before buying. Read speed is what matters when you’re transferring your files to a computer. Write speed, however, directly determines what your camera can do in the field.

A card with a read speed of 100 MB/s may well drop to 20 or 30 MB/s when writing. This discrepancy is common and perfectly normal. For a camera, it’s always the write speed you should look at first.

To help you find your way around, here’s a quick reference table based on usage :

What is the difference between an SDHC card and an SDXC card?

These are two formats belonging to the same family, but they do not meet the same storage needs. The main difference lies in the maximum capacity they can achieve.

An SDHC card, or High Capacity card, offers capacities ranging from 4 GB to 32 GB. It is a very common format, compatible with almost all cameras on the market. The AgfaPhoto 8 GB SDHC memory card falls into this category, ideal for regular use without unnecessarily cluttering up storage space.

An SDXC card, or Extended Capacity, takes over beyond 32 GB, up to 2 TB in theory. It uses the exFAT file system, which allows it to handle large files without restrictive limits. The AgfaPhoto 64 GB SDXC High Speed Class 10 U3/V30 memory card also falls into this category, designed for those who film in 4K or take numerous photos without wanting to change cards every hour.

Please note, there is one thing to check before buying: your camera must be compatible with the format you choose. A camera that only supports SDHC will not recognise an SDXC card. This information is always included in the camera manual.

How do you know which SD card to choose based on your needs?

Technical specifications are one thing. But knowing how to translate them into a practical choice is quite another. You don’t choose an SD card in absolute terms. You choose it based on what you do, how often you do it, and the camera you use. Here’s an overview.

Does the type of SD card I use for my camera matter?

Yes, and far more than we often realise. An unsuitable card won’t just slow your camera down. It can freeze video recording mid-shoot, overload the buffer during burst shooting, or cause file errors that are hard to predict.

Every camera has its own requirements. An entry-level compact will be less demanding than a recent mirrorless camera capable of shooting in 4K. Similarly, a camera that supports the UHS-II standard will derive no benefit from a UHS-I card, even a high-end one.

The type of card also determines how long your shooting sessions will last. Going on a trip with an 8GB card when you’re shooting in RAW means you’ll likely have to sort through your shots on the spot, which is really not ideal.

For example, the AgfaPhoto Micro SDHC 32 GB Class 10 SD card meets the needs of compact and bridge cameras that support the micro SD format, with sufficient capacity for a day’s shooting in JPEG or moderate RAW.

Photos, 4K video, burst mode: which memory card for which use?

Each use has its own constraints. Here’s how to approach them in practice.

In standard photography, portraits, landscapes, architecture, the files are relatively small. A JPEG file weighs between 5 and 15 MB depending on the camera. A RAW file ranges from 20 to 50 MB. A Class 10 card with 32 GB of storage easily covers a full day’s shooting.

Burst mode, however, places greater demands on the card. When you press the shutter button continuously, your camera accumulates the files in an internal buffer before transferring them to the card. If the card writes too slowly, the buffer fills up and the camera stops. To avoid this, a write speed of at least 30 MB/s – i.e. U3 or V30, is essential.

For 4K video, the requirements are even more specific. A 4K stream at 30 frames per second generates a continuous data rate that can exceed 60 MB/s depending on the codec used. A V30 card is the minimum recommended.

How do I know which memory card my camera requires?

The answer can be found in two places. Firstly, in your camera’s manual, where the manufacturer lists compatible formats and the minimum recommended speeds. Secondly, on the camera body itself, often engraved or printed near the card slot.

Here are some useful pointers. If your camera specifies UHS-I, opt for a U1 or U3 card depending on your usage. If it supports UHS-II, a UHS-II card will offer significantly faster transfer speeds, provided the card is also UHS-II. If your camera is older and does not mention any UHS standard, a good Class 10 card will suffice.

As for the physical format, check carefully whether your camera uses standard SD, microSD or CFexpress. Some cameras accept the first two via an adapter, but this isn’t always the case. The AgfaPhoto Class 10 64GB Micro SDHC memory card, for example, is suitable for compact cameras or drones that only accept the microSD format, offering ample capacity for long sessions.

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What is the best SD card for a camera: avoiding buying mistakes

The SD card market is saturated. Dozens of models, prices varying by a factor of three, and technical claims that aren’t always easy to decipher. In this environment, it’s easy to make the wrong choice. Understanding what really matters is a bit harder. Here’s some guidance to help you see things more clearly.

How do you know which SD card to choose from the options on the market?

The first mistake is to rely solely on price. An expensive card isn’t necessarily the best fit for your needs. And a cheaper card may well meet your requirements if its specifications match your camera and how you use it.

The second mistake you might make is to focus exclusively on the read speed advertised prominently on the packaging. This figure relates to transfer to your computer, not what happens inside your device. What matters in practice is the write speed, and this is often given far less prominence.

Finally, be wary of excessive storage capacity if your usage doesn’t justify it. A 256 GB card for taking family photos in JPEG is overkill. Conversely, setting off on a photo shoot with 16 GB when filming in 4K risks running out of storage at the worst possible moment.

For example, the AgfaPhoto SDHC 16 GB Class 10 SD card is ideal for everyday use and compact cameras. Where modest storage capacity is an asset rather than a constraint.

Capacity, speed, format: the comparison table based on your memory card usage

To choose the right memory card without making a mistake, nothing is more effective than a clear table. Here is a summary of the most suitable combinations based on usage profile.

This table is no substitute for reading your device’s manual, but it provides a solid basis for guiding your choice even before you open a product page.

The criteria that really make a difference when buying your memory card

Once you’ve identified your intended use and your device, there are a few additional criteria worth considering before confirming your purchase.

Firstly, focus on compatibility. Some cameras only support certain formats or UHS standards. A card that is technically superior to what your device supports will work, but without utilising its full potential. You might as well choose a card specifically designed for your equipment.

Next, consider reliability. A memory card stores memories, photo reports, and sometimes months of work. This is not the place to skimp on quality. Opt for brands that offer clear warranties and tested products.

Physical durability is also a factor if you’re shooting outdoors. Some cards can withstand shocks, humidity or temperature fluctuations. It’s a detail that can make all the difference in challenging conditions.

For photographers working in a studio or indoors with a recent mirrorless camera and who shoot mainly in RAW.

Choosing your SD card: the essentials

Choosing a memory card is no trivial decision. Behind a small plastic rectangle lies a technical logic that is best understood before you buy.

Bear three things in mind. Write speed takes precedence over read speed for photography or video use. The format SDHC or SDXC must match what your camera supports. And capacity should be chosen based on your actual needs, not on the maximum available on the market.

AgfaPhoto offers a range of memory cards designed to cover all these uses, from occasional shooting to 4K video in demanding conditions. Reliable products with clear specifications, so you can focus on what really matters: taking photos.