There are multiple threads discussing MicroSD cards and recording video. It is well established that the maximum data produced by recording video is 60Mbps or 7.5MB/s (all 4K and UHD is encoded at 60Mbps. Pretty much any Class 10 or UHS-I is capable of these speeds, (Class 10 and UHS-I are defined by a minimum sequential write speed of 10MB/s. That's been hashed to death, walk away. Where write speed really matters is in multiple exposure pictures. A 5 shot AEB (Auto Exposure Bracketed) J+R (JPEG+RAW) photo generates roughly 150MB of data that must be recorded to the card. Write speed here is crucial because the camera locks up until it completes writing the card (the spinning blue circle around the shutter button) and prevents you from taking another photo until processing completes and the data is written to the card. What I want to attempt is to shoot 5AEB pictures (on the bench) of a high speed timer (to measure time difference between exposures) and also measure the time we get the blue spinning circle. I will also examine the file write data on the card to measure the time lapse between writing the first and last file. My first attempt failed (mostly in a good way) because my finger obscured the subsecond readout on the timer, which is good because it suggests that the images are captured extremely quickly and copied to the buffer. It also failed in a bad way because there is little consistency in the "blue circle", with some photos taking 8 seconds and others taking 23 seconds (same card). The third failure was using the shutter on the remote made the "5shot" sound, but only reocrded 1 photo to the card (on my second test, first recorded just fine). For reference these are the cards I have handy measured using CrystalDiskMark 4.0.3 x64 (all figures in MB/s) CrystalDiskMark 4.0.3 x64 - Test Sequential Q32T1, 3 Pass, 1GB Sandisk Pixtor (Extreme Plus) 80MB/s 64G Read 90.58 Write 64 Lexar Professional 633X 16GB Read 87.82 Write 24.14 PNY SDXC U1 90MB/s 64GB Read 87.78 Write 55.38 Crucial M500 1TB SSD (just for fun!) Read 518.3 Write 439 I will attempt to pickup a Sandisk Extrteme Pro later today (Best Buy price match at $54.99) and add that to the testing. Why post now? I need suggestions for the best ways to capture valid test data that will measure any difference in camera performance on the bench that will be affected by the write speed and see if there is a performance difference between using a 24MB/s (stock), 64MB/s (Extreme Plus), or 90MB/s card (Extreme Pro). Thank you in advance for your suggestions.