<p>Hello Eric and everyone,<br>
looks like my issue is about to resolved. I mount all 4 lenses on my D90 and D7000 and tried to shoot same object on my table using single focus point with 9 AF at f2.8, 4, 5.6, 8 and it turns out my images are not that bad. Yes 85mm 1.8 is not very sharp nor at 5.6 comparing to 17-50 or 35mm. <br>
SO I think my technique wasn't right. I was using hand held camera but 100 shutter speed so images weren't blurry, and now I'm starting to believe that probably using good light ( it's 1am here) and tripod may give better result.<br>
Just one question I tried last night some shots using live view in manual mode and I think some images came even sharper, so was it the whole point of telling me to try this out? Or something else?<br>
Thanks Eric once again to resolve my problem and saving some $ to buy another lens. you guys are the best.</p>