When I first purchased the DA 55-300 I found it sharp. My only complaints were the AF was a little slow and noisy. In February last year I was using it on vacation and found it to be soft and almost all the shots were OOF.
I have tried it on the K5 and not much difference. It seems very soft and shots are OOF. I have tired all metering options , various focal lengths and even selective focus. I thought maybe camera shake so I tried setting in on a table and hand hold at 1/2000 of a sec. No improvement. I don't think it's a BF or FF issue as the whole image looks soft and OOF - and even the fence is soft which is pretty static
I think this had a 2 year warrenty so I may just bring it in. Any opinions ?
Examples below.
1/350 (could be motion blur or camera shake)
100 Crop
1/2000 should elimate motion blur and or camera shake
100 Crop