Lexar Professional 1066x 256GB CompactFlash Card, Up to 160MB/s Read, for Professional Photographer, Videographer, Enthusiast (LCF256CRBNA1066)

These work fine for my 5d mark iv. I needed lot of space and this did the job. Not problem so far.

Good reliable card.

I'm using this as an auxilliary drive on a very nice laptop that is, however, somewhat limited in its C: drive capacity. So I use it to store documents, graphics, and other data, but not for read/write intensive tasks. Seems to be doing a great job, replacing an older 64GB card by the same manufacturer. Good item, good value.

I really do not know too much technical data among so many features, but I'm using it in a Canon 5D Mark IV camera and it works perfectly even the card responds very fast when I do 7 shots per second in RAW

If speed is all there is to consider when selecting a CF card for 4k video recording, this CF card certainly delivers. Durability/Reliability remains to be seen so I'm holding back on that note. I'm relying on other users' review on reliability/durability. If i have to raise a negative point, i have to say it's the price. I sure hope I'm getting what I paid for. So far, so good -- so i'm recommending this to a friend.

This item did not work. I then bought another from a different source which worked fine.

The fastest cameras I own are: (A) D800 and (B) D7100 The D7100 is SD-only, so that leaves me with the D800, D700, and D300s cameras that can use these CF cards. The D300s and D700 Card slots don't write NEARLY fast-enough to take advantage of these cards over my Lexar 1000x or even 800x cards. So while these DO offload faster to my computer through my USB 3.0 reader, there is no advantage to these for me beyond off-loading photos to my PC faster through the card reader. The D800 only fires at 4FPS when I use 14-bit RAW + JPEG Fine, so it's not like my shots come noticeably faster. Now with a D4/D4s I can see where there would be a big advantage with these cards. I imagine that the Canon camp will experience much of the same, but I can't say for sure since I never use Canon DSLR cameras myself. Either way, I am getting these so that I am future-proof when the next gen of Nikon cameras that use faster card writing become available...

Nice

It works perfectly fine! The only thing is, if you are trying to film in 4K 60 FPS... on a canon 1dx mark II, it will not be fast enough :( but other than that it works as described!!

I bought this card for my Canon 5D Mkii and was disappointed to find that the camera cannot format it for use. I have a Lexar professional 128GB and it works very well but the camera does not seem to work with the 256GB capacity. Check compatibility before buying.

Excellent product quality, fully satisfies my needs.

works perfectly