Thanks for reply Hank,
I am using t70-300 more than one year, and did several trials; tripod, mirror lock-up,
aperture and shutter values, different light conditions.
Sometimes it produce good results, but generally not. I think it has focus problems,
and it needs very precise focussing in order to obtain better results.
Or my copy is not so good.
But when I look 55-300 results, they seem much more usable results than my tamron.
Here some
good examples;
iso100, 300 f5.6 1/320
http://farm5.static.flickr.com/4119/4923366073_bd19d2717e_b.jpg
iso100, 300mm f11 1/320
http://farm5.static.flickr.com/4080/4909804027_17b9cd1d83_b.jpg