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I'm reading conflicting comments on use of hi speed sync with the 600EX-RT and aperture priority.  Will the MKIII do so?  Or do I need to go to manual?  Also, will the ST-E3-RT transmitter allow hi speed sync with MKIII in aperture priority and the 6...
Will the Canon MR-14 EX 11 Macro Ring Lite Work with a Sigma 105 mm 1:2.8 DG Macro Lens with 58mm opening?
Does the Canon GPS GP-E2 work well with the 5D Mark III?