topic Re: EOS-1D X Mark II not using memory card's full capacity in EOS DSLR & Mirrorless Cameras

EOS-1D X Mark II not using memory card's full capacity

Sportseditor123 — Sat, 23 Aug 2025 12:07:46 GMT

I just got a used 1DX Mark II.

I've got a 64GB SanDisk CFast 2.0 Extreme PRO memory card and a SanDisk Extreme 128 GB compact flash card.

The camera switched storing photos from the CFast card to the SD card after 3.67 GB on the CFast card.

I wasn't notified that it switched and I'm perplexed why it did that when there was plenty of storage left.
I shoot RAW.

Thank you for any help.

Re: Memory card issue on 1DX Mark II

deebatman316 — Sat, 23 Aug 2025 00:31:49 GMT

Let me ping @Rodger he is a 1D series camera user.

Re: Memory card issue on 1DX Mark II

shadowsports — Sat, 23 Aug 2025 02:03:09 GMT

Greetings

The 1DX Mark II formats CF Express cards using exfat. A 4 GB card will yield a formatted capacity of approximately 3.72 GB. A small portion of this is reserved for the file system, hence why you see 3.67 GB available. 😉

Re: Memory card issue on 1DX Mark II

Sportseditor123 — Sat, 23 Aug 2025 08:31:52 GMT

I've got 64 GB card.

Re: Memory card issue on 1DX Mark II

Peter — Sat, 23 Aug 2025 11:03:02 GMT

1D X II with certain SanDisk cards had an issue until 1D X II was updated to 1.0.2.

Though the symptom was different.

"If a SanDisk CFast card is inserted into the camera or a card reader, the bottom part of still images recorded may be corrupted.
This phenomenon is confirmed in images recorded in both the RAW and JPEG formats.
In the RAW file, the image corruption may appear in the bottom right corner of the image.
In the JPEG file, the image corruption may appear in the lower third area of the image.”

Affected cards.

SanDisk Extreme PRO CFast2.0 64GB (SDCFSP-064G-xxx)
SanDisk Extreme PRO CFast2.0 128GB (SDCFSP-128G-xxx)
SanDisk Extreme PRO CFast2.0 64GB (SDCFSP-064G-xxxA)
SanDisk Extreme PRO CFast2.0 128GB (SDCFSP-128G-xxxA)
SanDisk Extreme PRO CFast2.0 64GB (SDCFSP-064G-xxxB)
SanDisk Extreme PRO CFast2.0 128GB (SDCFSP-128G-xxxB)

Re: EOS-1D X Mark II not using memory card's full capacity

Waddizzle — Sat, 23 Aug 2025 14:14:58 GMT

Did you open the card slot door, at all?

Is this your first experience with a camera body with dual card slots?

Re: EOS-1D X Mark II not using memory card's full capacity

shadowsports — Sat, 23 Aug 2025 15:08:30 GMT

Greetings,

Thank you for clarifying. I missed the 64 GB In your comment. I've not seen the destination media change just by opening the door. It happens when one of the cards is physically ejected and the door is closed. I often open the door eject my CF Express B card extract images and video using a card reader then return it to the body without closing the door. I did do it once years ago and ended up with everything on my SD card. I was very concerned for about 3 seconds 🤣.

@Peter This is helpful information I've not read up much on the 1DX Mark II 👍

@sportseditor123, By chance was this card formatted outside of the camera? What does its formatted capacity appear as?

Re: EOS-1D X Mark II not using memory card's full capacity

Waddizzle — Sat, 23 Aug 2025 16:22:45 GMT

Thanks, Rick. I forgot to point that out. The phone rang and I got distracted.

There’s more to it than opening the door to the card compartment. You have to remove a card and then close the door. This may cause the camera to switch to the other card, if the card you removed was the primary card to save photos.

Re: EOS-1D X Mark II not using memory card's full capacity

Sportseditor123 — Sun, 24 Aug 2025 08:05:32 GMT

Did not open door.

Yup, upgraded from a 7D.

Re: EOS-1D X Mark II not using memory card's full capacity

Sportseditor123 — Sun, 24 Aug 2025 08:06:26 GMT

I didn't open the card door compartment.