The A7S is Sony's newest entry in its full-frame mirrorless lineup. But where the 'R' in A7R stood for resolution, the 'S' in the 12MP A7S stands for sensitivity, topping out at an impressive maximum ISO sensitivity setting equivalent to ISO 409,600. We've had an A7S for a couple of days - just long enough to create a real-world comparison of high ISO stills from the camera against the 36MP A7R and Canon's EOS 5D Mark III. Click the links below to see the results.