Tair 3a 300mm - Focus problem

[ecniv]

Hi,

Probably user error but the pics I'm getting on the d300 plus adapter are a bit soft.

After one or perhaps two unsharp masks they look better.

My question :
Is there some settings I can play with that will assist in getting the most out of this lens?

I am thinking of the fine tune as when looking through the viewfinder the pic seems crisp and sharp, but after taking its soft.

Now I know you might say its the 15ukp adapter I got. If thats the case, which brand and sort of cost would you recommend to get?

I bought a cheap ring adapter, but it twisted on the mount and was difficult to get off... plus with no infinity, really cut the 300mm down.

A link to the m42 pics...
http://www.flickr.com/photos/katiauk/sets/72157626218095209/

The last ones from silverstone are handheld and my first proper attempt at taking pics with the 300.
The moon pics are on a tripod, with and without a vivitar 2x
The Southport/Blackpool in the distance pics are hand held in fairly bright but dull light.