I assume on board flash fixes shutter at 1/60th.  My problem on initial TC test was shutter speed at high focal lengths.  TC test using 70-200 employed higher shutter speeds due to external flash and shorter focal lengths. 
  
I'll look forward to the shoot out between 70-200 and 300, try to use a subject with lots of detail and move 200 closer to frame the same as 300.
		 
		
		
		
		
		
		
			
		
		
		
		
		
	
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