This page assesses focus shift and color bokeh at a distance of about seven feet = ~2.2 meters.
Focus shift should be absent with an f/4 lens, and indeed there is no evidence of it.
The typical magenta foreground and green background is observed, but appears to be about the same as the Nikon 300mm f/2.8G VR II, which means fairly well corrected. But for an f/4 lens, it’s neither good nor bad, just reasonable. Stopping down to f/5.6 eliminates most of the color effects.
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Since 2006, Diglloyd Advanced Photography is the authoritative review and reference for DSLRs and their lenses: Canon and Nikon primarily, but also Pentax and some medium format. Reviews of key DSLRs are included, but the primary focus is on lens performance. Also included is a wealth of technique and workflow approaches.
DAP includes thousands of pages of exclusive coverage and high resolution Retina-grade examples detailing Canon and Nikon DSLR bodies and their lenses, with in-depth analysis of sharpness and contrast, color, bokeh, vignetting, distortion, MTF, and flare, behavioral and practical usage.