GH3 won't write HD video to Sandisk 32MB 45MB/s card

[beemerbiker]

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.

[jonpais]

Not sure why it's not working properly. Not only does the SanDisk Extreme Class 10 45MB/s card work in my GH3, it also reads and writes 4K in my GH4.

[beemerbiker]

Thanks for your comment, john paid. That gives me some reassurance.

Ok. I've today tried out the GH3 with different card of different make from a different supplier: the PNY Class 10 Elite advertised at 100MB/s read and 65MB/s write (ie even faster than my Sandisk). I just wanted to establish that the fault lay with the card and not the camera (as both were new). It works perfectly, even at the top MOV data rate of 72 Mb/s. So the camera is fine and the Sandisk card is working at no more than 10% of it's advertised write speed. At least I know where I am and I can progress from here, trying some other cards too.