However, Microsoft offers MBR2GPT.EXE that can convert a disk from the Master Boot Record (MBR) to the GUID Partition Table (GPT) partition style without modifying or deleting data on the disk.

For all modern Macs, GUID Partition Map is the only choice and it nearly never needs to be changed; Master Boot Partition is useful for cross-platform drives that can be mounted in Windows and in ...

I want to partition the card so I can use it for an OS install disk (Mac OS Extended GUID) in one partition and as a camera disk (MS-DOS FAT) in the other partition.

However, there's an asymmetry here. Although a PPC machine cannot boot up from a GUID-partitioned disk, an Intel machine can boot up from an Apple partition scheme disk.