A look at the exif info shows why this camera/lens combo is working so well for me.
The lack of noise at ISO 1250 makes possible the f7.1 or usually f8 I need for this lens/2X TV combo.
This was from a tripod but I do handhold at this speed. Less is okay but only if nothing wiggles.
If I open lens fully it gets a shade mushy and if if ISO or speed is low it gets worse.
This photo is a medium crop and no noise reduction is used.