Pentax HD D FA 24-70mm f/2.8 SDM ED Aperture Series @ 29mm: Backlit Sprinter on White Mountain Road (Pentax K-1 II)
See my Pentax K wishlist at B&H Photo. Deep discounts are seen on Pentax K-1 Mark II and lenses today.
This medium range aperture series at 29mm shows why it is important to account for the field curvature at 24mm and at 40mm, namely, that the usual assumptions about focus placement need to be substantially modified to obtain full sharpness. A discussion is included of how to to do and thus reliably obtain higher total sharpness for any obliquely-shot scene like this.
Includes images up to full camera resolution from f/2.8 through f/9.