# SD CARDS UHS-|| and CF Cards



## ronaldbyram (Nov 5, 2015)

I am a New Owners of a 7D Mark || 
Question does anyone know if the UHS-II type SD cards will work with it? Looking at the Lexar 1000x card

Also is there a point of Over Kill for speed of cards vrs Bus of the Camera for Read/Write?
Looking at the 100 CF card too.

Thanks ;D


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## Pancho (Nov 5, 2015)

Hi ronaldbyram,

The 7DMarkII is not compatible wih UHSII. The card will work in UHSI and the performence may be very low compared to a lower cost optimized UHSI card.
See this site for optimum cards used with 7DMarkII:
http://www.cameramemoryspeed.com/canon-7d-mark-ii/fastest-sd-cf-card-comparison/


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## Mt Spokane Photography (Nov 5, 2015)

They will work with it, just not at UHS-II speeds. 


Beware of the maximum speeds advertised, they are only for a new totally blank card. Look at the actual specs for minimum speeds with a fragmented card, which is what you will have when you have written to a card and formatted it. 30 MB/sec minimum write speed. Not so good as the 100+ advertised. You can do a low level format and blank the card again, but when you do that often, it decreases the life of the card drastically.


A CF Card delivers close to the advertised speed. IMHO, CF is better.


From Wikipedia:



Speed class rating



The SD Association defines standard speed classes indicating minimum performance (minimum serial data writing speed) to record video. Both read and write speeds must exceed the specified value. The specification defines these classes in terms of performance curves that translate into the following minimum read-write performance levels on an empty card and suitability for different applications:[20][23]



ClassMinimum Serial Data Writing SpeedApplication

 Class 22 MB/sSD video recording

 Class 44 MB/sHigh-definition video (HD) recording including Full HD (from 720p to 1080p/1080i)

 Class 66 MB/s 

 Class 1010 MB/sFull HD (1080p) video recording and consecutive recording of HD stills (high-speed data bus)

 UHS Speed Class 1 (U1)10 MB/sReal-time broadcasts and large HD video files (UHS bus)

 UHS Speed Class 3 (U3)30 MB/s4K video files (UHS bus)
Speed classes 2, 4, and 6 assert that the card supports the respective number of megabytes per second as a minimum sustained write speed for a card in a fragmented state. Class 10 asserts that the card supports 10 MB/s as a minimum non-fragmented sequential write speed and uses a High-speed bus mode.[20] The host device can read a card's speed class and warn the user if the card reports a speed class that falls below an application's minimum need.[20] By comparison, the older "×" rating measured maximum speed under ideal conditions, and was vague as to whether this was read speed or write speed.
UHS-I and UHS-II cards can use _UHS Speed Class_ rating with two possible grades: class 1 for minimum read/write performance of at least 10 MB/s ('U1' symbol featuring number 1 inside 'U') and class 3 for minimum write performance of 30 MB/s ('U3' symbol featuring 3 inside 'U'), targeted at recording 4K video.[26] Before November 2013, the rating was branded _UHS Speed Grade_ and contained grades 0 (no symbol) and 1 ('U1' symbol). Manufacturers can also display standard speed class symbol (a digit encircled with 'C') alongside UHS speed class.


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## ronaldbyram (Nov 5, 2015)

Thanks gang for the Great reply's to my question. 
I went ahead and ordered a Lexar CF Card and skipped the UH2 card will use my UH1 633x 

Planning on Wildlife (Birds at the Outer banks of NC next month.) getting setup!


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