Q: Can I use a micro sd 64 Go sdxc with camera connector on my new ipad (3rd gen)?

The supported formats are, from http://support.apple.com/kb/HT4101 :

Here are the supported SD cards and image-transfer protocols:

• Picture Transfer Protocol (PTP)
• Mass Storage Device protocol
• SDSC
• SDHC
• miniSD
• microSD
• MMC
• SDXC (supported only when not formatted as ExFAT)

If you reformat it at fat32 it might work, but some have reported a loss of capacity when reformatting...for example one person could use her SDXC reformatted but only got 32 gig not 64.