Today I got my brand new Panasonic GH3. I also got two Sandisk Extreme 45MB/s cards from Amazon. With trembling fingers I inserted the card and gave the camera its first test. Imagine my disappointment when I found that it cut off video recording after about 20 seconds with the message that the card write speed is too slow. This happened first with AVCHD FHD 50p (28 Mb/s). I reformatted the card (in the camera) and tried again. Same result. I reformatted again and tried AVCHD FHD 50i (17 Mb/s). Same result.
Then I tried MP4 FHD 50p (28Mb/s): failed. MP4 FHD 25p (20Mb/s): failed. Then MP4 HD 25p (10Mb/s), and that worked! But come on, guys, a 45Mb/s card (ie 360Mb/s) can't record any HD video?
This is a brand new card from a reputable supplier. At first I thought the problem was connected with the bewildering fact that the camera displayed a maximum record time of 29m 29 secs for an empty 32MB card, but I discovered from this forum that that misleading information is present on all EU models, so it's not that.
For what it's worth, the 20 secs or so of video that is recorded plays OK on the camera and on my computer. Can anyone shed any light on my problem? Heard of it before? Is there any way to test the record speed of the card outside the camera? I'm reluctant to unseal the second card of the same make and spec until I know what's going on. Did I say I'm new to video? I am.
Many thanks.