> What would the 5T or the 6T produce in terms of macro magnification on > the 70-300 at 300? Would it be 1:2, 1:1, or greater than 1:1 ratio? Ross, I think the 70-300 will get close to 1:1 with the 6T and about 1:2 with the 5T. Check out the intruction sheet for your lens, it may give reproduction ratios when used with closeup filters, extension tubes... Roland
