Buying memory card for camera, phone seemed to be very simple. But if not knowing these parameters, you are very easy to make mistakes such as buying the right counterfeit cards, cards of inferior quality, or even card is corrupted. 1. Buying a incompatible card All microSD card can fits into the device there microSD slot, but not all of them work. There are 3 different standard formats of the memory card user to determine the compatibility includes SD, SDHC and SDXC (or microSD, microSDHC, and microSDXC). The format standard isn’t compatible with each other and so that you can’t use a memory card with a new format standard on the hardware only supports the old format standard. The difference between the 3 standard formats: microSD card: capacity about 2 GB, compatible with a device any can microSD slot. microSDHC memory card: capacity from above 2 GB to 32 GB, compatible with devices that support standard SDHC and SDXC. microSDXC: capacity from 32 GB to 2 TB (to the current time memory card this format has the largest capacity of only 512 GB), compatible only with devices that support standard formats SDXC. Beside checking format memory cards are compatible with your device or not, you also need to check a few more other factors. Ultra High Speed – UHS Standard format the SDHC and SDXC memory cards support Ultra High Speed (UHS) protocol – using new circuit for faster data transmission quality. UHS has two version is UHS-I with data transfer rate up to 104MBps and UHS-II up to 312MBps. 2. Select the wrong speed Similar to the identification of the standard format and compatibility, determining the speed of a memory card is also quite complex. There are 4 ways to determine the speed of a memory card. Based on the Speed Class Speed Class is the minimum write speed of a memory card, measured in megabytes/second (MBps). Speed Class 4 standard, including: Class 2: minimum write speed is 2MBps. Class 4: minimum write speed is 4MBps. Class 6: minimum write speed is 6MBps. Class 10: minimum write speed is 10MBps. In summary, memory cards have the higher class, the faster speed. Based on the UHS Speed Class UHS Speed Class is the minimum write speed that the memory card supports microSD UHS-I and UHS-II can reach. U1: minimum 10MBps U3: minimum 30MBps Based on the number of speeds on the card (Rated speed) Some manufacturers print the maximum speed up on their products, measured in MBps. However, this is only the speed on the theory, in terms of the ideal of the laboratory, not a real speed. Actually, read and write speed of a memory card depends on many factors such as device configurations, and even the USB cable you are using… 3. Use wrong function of the card Choose a memory card in accordance with the purpose of use is the most important thing. The memory card standard UHS-II U3 will often be fast paced, however the price quite high and you usually do not take advantage of the performance of it. According to Panasonic, if your purpose is recording videos in 4K, you should use a memory card UHS Speed Class 3 (U3). For Full HD video, genuine this advice you should use Class 10 or Class 6. If the read and write speed of the memory card is too slow will lead to the lost frames (dropped frames) or video is jerky (shuttering). For photography, use multiple small cards instead of one big card would be more suitable because this will help minimize the risk of losing all the photos when the memory card is defective. If you often shoot in RAW (file capacity from 25 MB upwards), you should use the SDHC card that supports standard U1 or U3. 4. Bought fake card The card maker author often fool users by setting up cards so that capacity of memory card like with the amount printed on the box. You won’t realize this until noticed the memory card filled up in an unexpected way. If you want to know memory card you are using is genuine or not, please use the utility H2testw (Windows) or F3 (Mac, Linux) to test.