Quick Answer

For camera storage, three specs decide everything: capacity (how much you can record), write speed (whether the card keeps up with your camera's data rate), and video speed rating (the standardised minimum write guarantee for video codecs). Get those three right for your specific camera and workflow and everything else is secondary.

Understanding Capacity: How Much Is Actually Enough 📦

Capacity is the most visible spec but also the easiest to misjudge. A 64GB card holds roughly 85 minutes of 4K footage at 100Mbps, around 2,100 RAW files from a 24-megapixel camera, or thousands of JPEGs. A 128GB card doubles those figures; 256GB doubles again. The practical question is not maximum storage but how long between offloads. South African event photographers working full-day weddings commonly carry two or three 128GB cards rather than one large card, creating a natural rolling backup. For videographers on multi-day travel shoots without regular laptop access, a single 512GB card priced around R1,200 to R1,800 locally makes more sense than juggling several smaller ones.

Write Speed: The Spec Your Camera Actually Cares About 🔧

Write speed is the rate at which data flows from your camera sensor into the card. It is almost always lower than read speed, and it is the number that matters for recording. A card advertising 160MB/s is usually quoting its read speed; the write speed may be 60MB/s or 90MB/s depending on the model. For 4K video at 100Mbps you need a sustained write speed of at least 12.5MB/s, but the V30 standard (30MB/s guaranteed minimum) provides a comfortable margin. High-bitrate codecs used on professional bodies like the Sony FX30 or Lumix S5 II demand V60 (60MB/s minimum) or higher.

Video Speed Ratings: V30, V60, V90 and What They Mean 🎬

The Video Speed Class guarantees a minimum sustained sequential write speed under video recording conditions. V30 means 30MB/s minimum and covers 4K at standard bitrates up to roughly 250Mbps. V60 means 60MB/s minimum and handles 4K high-bitrate and some 6K formats. V90 means 90MB/s minimum and is required for 8K or Cinema RAW formats. U3 (Speed Class 3 within the UHS system) also guarantees 30MB/s and aligns with V30. Class 10 and U1 only guarantee 10MB/s, which is fine for 1080p but not 4K. When buying a card in South Africa, V30/U3 is the sensible minimum for any current camera body shooting 4K.

TIP

Match the Card to the Camera Body ⚡

Before upgrading to a V60 or V90 card, check whether your camera actually has a UHS-II slot. UHS-II cards in a UHS-I slot revert to UHS-I speeds, so you pay a premium for no gain. The Sony ZV-E10, most entry Nikons, and mid-range Fujis all use UHS-I. Only professional bodies like the Nikon Z8 or Sony A1 fully exploit UHS-II.

FAQ

Can I use a microSD with an adapter in my camera?

Yes, and the adapter does not reduce UHS-I transfer speeds in practice. However, microSD cards in the same speed class are often slightly slower in real-world sustained write due to the smaller flash die. For critical video recording, a native full-size SD card is the safer choice.

What happens if my write speed is too slow for my camera's bitrate?

The camera's internal buffer fills up and recording stops, often mid-clip. Some bodies display a warning; others just halt. You cannot fix this in settings; you need a faster card that meets the camera's minimum write speed requirement listed in the manual.

How do UHS-I and UHS-II differ in practice?

UHS-I has a maximum theoretical bus speed of 104MB/s. UHS-II adds a second row of pins and reaches up to 312MB/s. In the South African market, UHS-II cards are typically R1,500 and above for 128GB, and are only worth the cost if your camera body supports the UHS-II bus.

Need a card that matches your camera's specs? Browse the range of SD and SDXC cards stocked at Evetech, with options from V30 through to V90 to suit every camera body and shooting style.