You have some control over how these memory card slots are managed. You can treat them as sequential memory so that when one card fills up, it automatically switches over to the next one. You can copy to both simultaneously to create a mirrored backup version. Or you can send image files to one and video files to another.
The D850 also has a built-in function that lets you copy from one memory card to the other.
A couple of common reasons you might want to do this are:
- To create a backup on a second memory card. Backing up onto memory cards isn’t ideal. They’re not well designed for long-term data storage. There are better devices designed for the purpose. But it can be hard to beat the convenience of creating a second copy on such a tiny and resilient storage medium, especially if you’re out traveling. And it can be especially useful if you’re trying to physically separate backups to make it less likely that they’re all stolen or lost if your pocket gets picked or the airline loses your bag. You might have one copy in your camera bag and another in the safe hands of a traveling companion, for example.
- To copy to a more compatible memory card type. When I’m traveling, I tend to work from an iPad Pro and shoot with a bunch of different cameras, some of which use memory card formats like XQD or CFexpress. And sometimes, I need to do a quick edit of a handful of images (the “proper” edits I usually do on a desktop at home). Yes, I could take a range of different memory card readers with me. But that means more to carry (and potentially lose) and more expense. If I was routinely editing images on the road, this would absolutely be the way to go. But I prefer to leave most of my editing until I get back, where I have a very good XQD/CFexpress B reader. And yes, I could connect wirelessly to the camera, but I just find that unnecessarily tedious. Since it’s not something I need to do routinely, sometimes it’s just quicker to copy from the XQD or CFexpress card to an SD card and then use that for connecting to my iPad. Because while the iPad Pro doesn’t have a built-in SD card reader, SD card readers are a dime a dozen, and many cameras have at least one SD slot.
You find the copy function under the playback menu. From the icons at the left of the screen on the menu, that’s the top one with the triangle inside a rectangle. Scroll down to:
Playback Menu > Copy image(s)
You have some choices to make to control how the operation will work. Work your way down from the top of the screen.
1. Select Source
The first is to Select source. This is where the original images you want to copy are stored. The available options are “XQD card slot” and “SD card slot.” But you may not have both available. That’s because it will only allow you to select a memory card that actually has photos or videos stored on it. Put another way: if a card is blank, you won’t be able to select it as the source (which makes sense).
Once you select one, it will take you back to the previous screen, and you’ll notice that the small icon next to “Select source” has changed to the appropriate graphic.
NOTE: If you’re using a CFexpress B card in your D850 instead of an XQD card, the menu system doesn’t pick that up and will continue referring to the XQD slot regardless.
2. Select image(s)
If you want to backup everything, select “All images in slot.”
If you want to choose only some of the images, go down to the next option, which will include one or more folder names. When you click on the right side of the selector wheel, you’ll then see these options:
- Deselect all. This is useful if you only want to copy a small number of images. On the next screen, you can choose the individual images that you want to select. In that case, it’s quicker to select the ones you do want to copy than to deselect the ones you don’t want to copy. Once you’re on the next screen, you can scroll through the image thumbnails and select by pressing the center of the dial (a small white checkmark will appear on the thumbnail). When you’re happy with the selection, press the OK button (not the center of the dial).
- Select all images. This is the natural choice if you’re looking to copy all or most of the images on a card (or, more precisely, in a folder). In this case, it would be quicker to deselect any you don’t want to copy rather than go through and individually select all of them. When you go to the next screen, all of the thumbnails will have a small white checkmark. You can deselect (or unselect) them by highlighting the thumbnail with the yellow border and then pressing the inside of the dial. When you’re happy with the selection, press the OK button (not the center of the dial).
- Select protected images. This is a useful workflow shortcut. If you’re in the habit of write-protecting your keepers in the camera, this is like a smart folder that only selects those protected images.
3. Select Destination Folder
This is where you can specify the folder on the target card where the copied images are placed. You can choose an existing folder or create a new, numbered folder.
It’s not required that you change this, but I do find that the ability to create a new, numbered folder can be useful for keeping the backed-up images separate from anything else that might be on the card (if, for example, you’re saving videos to the second card, etc.).
On the screen where you’re specifying the destination folder, you’ll notice that one of the memory card slot icons at the top right is yellow. That’s confirming the target slot.
4. Copy Image(s)
This is pretty self-explanatory. It’s the go-for-launch command.
Things Worth Knowing
Be sure not to interrupt the copying process. That might lead to data loss or data corruption.
You have some control over managing how the memory cards in the D850 are used. You can treat them as sequential memory so that when one card fills up it automatically switches over to the next one. You can copy to both simultaneously to create a mirrored backup version. Or you can send image files to one and video files to another. I have a more detailed post on that here.
And there’s a shortcut to format memory cards in the D850. You can find more information on that here.
- The CFexpress B compatibility with added in a firmware update in late-2020. If you haven’t updated to that (or newer) firmware, the camera won’t register a CFexpress B card in the slot. I have more information at the link. ↩