I did one test: the brick wall! Trinity College's Tudor brick chimney. The 70D and the 5DIII were on a tripod for this test, both at f/8 and 600mm with the Tamron. From top to bottom; 70D scaled down to 1200x800; 5DIII scaled down to 1200x800; 100% crop from centre of the full-sized 70D; very bottom, the centre from the full-sized 5DIII upscaled by 1.5x. If you crop the centre 200x200 the 70D is slightly better, but the image is too small anyway to be of any use.
Both lenses were AFMAd 3xtimes, Dilbert.
I think the 5DIII image is better. But, it's only one example under one set of conditions.
« Last Edit: February 17, 2014, 03:50:06 PM by AlanF »
5D IV, 5DS R, 7D II, EOS-M, Powershot G3 X, 400mm DO II, 300/2.8 II, 1.4xTC III, 2xTC III, EF 1.8 STM, EF 70-200/4 IS, EF 24-105, 15-85, 100-400 II, Sigma 10-20, Sigma 150-600mm C, EOS-M 18-55, f/2 22, 11-22