Just got a 300mm Raxatar f4.5 lens and am using it with a Vivitar doubler. The photo is in focus but it seems dull. It was a cloudy day and there is added glass of the doubler, the adapter (Minolta MD to Pentax0 and the sliding glass doors. Still it seems a little blahh to me. So I have some work to do.Nothing worth while talking about. Just a retired guy with a hobby.