Some of the "Wall" images didn't use a tripod, and all used a lenshood (because I forgot that the lenshood may contribute to vignetting because of the wider field of view). The "Target" images used a tripod and 2-second delay and no lenshood. No filters were used.
I used aperture priority and autofocus throughout.
|(None)||300||f/4||f/8||f/4||f/5.6 (camera shake?)||f/8 (poor focus?)|
|1.4 (Kenko)||420||f/5.6 (f/4 on camera)||f/8 (f/5.6 on camera)||f/11 (f/8 on camera)|
This is an excellent (and expensive) lens, but by itself it was a dubious purchase. It adds little to the reach of my DA* 60-250mm f/4, and for some purposes such as airshows is doesn't always have the field of view I want. I always intended to couple it with the Pentax 1.4x Teleconverter to extend the reach when that is available. A combination of a Pentax FF camera and this lens, and a choice of whether to use a teleconverter, should make this a more usable lens. (Although it will still be competing with the DA* 60-250mm f/4, of course, if that too works on a Pentax FF camera).
This simply acts like an FF lens, without qualifications.