Sorry, I don't have expensive Ltd glass
I ran this test with the FA 50mm f/1.4, and the DA 18-55mm f/3.5-5.6 (just for laughs). I focused manually (on the '2' in '2.8'), and now I'm at the computer I see that the FA 50 was a little bit out of focus, but still pretty good; I apologise for this. Shots were taken on tripod with 2s MLU, in available window light. I used Av because I felt the Tammy underexposed a bit and wanted to test this out too. And it does expose about 1/3 stop lower than the FA 50. The box was about 80cm away, which is not the best range for the Tammy, and explains the dreamy appearance at f/2.8. Don't confuse this with lack of sharpness! The
Milk Effect (TM) (as I call it) goes away when you focus further away. You'll have to click through for the 100% versions (1233x986 pixels).
Tamron @ f/2.8
FA 50 @ f/2.8
Tamron @ f/4
FA 50 @ f/4
Tamron @ f/5.6
FA 50 @ f/5.6
DA 18-55mm @ f/5.6 (auto-focus)
I hope this helps!