Pentax HD DA 28-45mm f/4.5 ED AW SR Aperture Series @ 45mm: Riparian Forest (645Z)
Get Pentax 645 and Pentax 28-45mm f/4.5 at B&H Photo.
The Pentax HD DA 28-45mm f/4.5 ED AW SR is equivalent to a 23-36mm lens on a full frame DSLR (long frame dimension).
At about $4697 it’s a substantial investment, but it does cover a very useful range. The main thing is that it is huge and heavy, much more so than its 35mm f/3.5 sibling.
This outdoor far-field scene explores the consistency of sharpness across the field at a uniform distance at the 45mm zoom setting, giving an excellent insight into what apertures are required for peak quality.
Pentax HD DA 28-45mm f/4.5 ED AW SR Aperture Series: Riparian Forest
Includes image sizes up to 25 MP , along with very large crops, at f/4.5, f/5.6, f/9, f/11 plus RawDigger exposure info.
This finely detailed image cries out for viewing on the iMac 5K (or at least a 4K display) so as to render the fine details of twigs and bark and moss in a far more compelling way than a standard display.

PENTAX 645Z + HD PENTAX-DA 645 28-45mm F4.5ED AW SR @ 45mm
[low-res image for bot]