Memory card problem

Kondwani

Kondwani

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53
Name
John
Edit My Images
Yes
My Canon 7D Mkii has been using a 64 GB SanDisk Extreme CF card (120 MB/s) for RAW images with no problems but recently started to use the SanDisk Extreme SD card (90 MB/s) for backup jpg images. I have found that several jpg images are missing which I am assuming is due to the lower read/write speed of the SD card.
Has anyone had similar issues and would a faster SD card cure the problem or have I got a corrupt card ?
 
The only thing I recall about the Canon implementation of the CF & SD card (in the 5D3 and others?) was that the write speed of the CF was limited to the max speed of the SD slot card.

I cannot recall any reports of missing JPEGs when writing RAW to CF and JPEG to SD???
 
I use 90MB/s for both CF and SD cards 64GB with no problem in my Nikon D810. All i can think is which card do you use as the primary and which as the backup. Other than that continuous shooting until the camera hit the buffer may be a cause. I deliberalty matched the two cards for MB/s at 90 so they more or lesss balanced allowing for my primary CF card to handle RAW files and the SD for Jpeg fine.
 
I use the CF as primary as its faster for continuous shooting, not that I shoot any more than 3-5 shots at any one time. I used to have the SD set up as a backup for when the CF was full but recently have set it up to copy images in jpg for ease of quick viewing. It's interesting that an inbalance of write speed between the cards could be causing it. I will have to do a check by running a series of single shots and then a series of continuous shooting (both fast and slow speed).
Thanks for your input.
 
Don't forget the speed 'printed' on the card is the "Read" speed. The write speed is AFAIK always slower......as are my most recent SD are 170 / 90 SanDisk Extreme Pro.

As mentioned, in Canon with CF and SD slots if you have a card in the SD slot it matters not what the card speed is, the slot speed control(er) is slower than the CF slot. And that then reduces the speeds of the VF slot.

Whether either of the above is the reason for your problem, I am not sure???
 
I had a Sandisk 90mb/s card corrupt on my 5d4 a few weeks back. Since getting the images off it (EaseUS software - not cheap at all), having formatted the card, it now seems fine... My take is that I took the card out to look.at it on my laptop. I probably rotated a few jpgs (I take raw and jpg), which upset the order of the data and caused an issue....

The absolute maximum that a 5d4 can write at is 110mb/s (if I recall correctly). Not sure what it is for the 7D2. Considering the camera has internal RAM that is faster, I think it is unlikely that data would simply vanish into thin air if the external card were slower. That would be a well known problem (and an embarrassing one for Canon)
 
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