What have you done with your Nikkor 105/2.5 mounted on the F4? .....that is your portrait lens!
I came relative late into the darkroom but had some few fun years with Ilfochrome......took a lot of time and money.....but I learned to work in 100% darkness......
As I have said before: I sold all Ai/Ai-s Nikkors.
I used some Nikkors (always adapted on digital Canon 5D I/II/III or analogue Nikons): My 'Problem' are the 46 MP of the D850...
Micro Nikkor Auto 55mm 3.5 (adapted on 22MP Canon really great surreal sharpness and good Bokeh; optical on 46MP D850 not bad but not so good as on 22MP - Bad Ai-Adaption destroyd some Parts of my D850)
Micro Nikkor 105mm f/4 (great cheap Makro on Canon 5D )
Micro Nikkor 55mm 2.8 Ai-s (good allrounder on 5D)
AF Micro Nikkor 55mm 2.8 Ai-s
Nikon 105, f/2.5 Ai/Ais (Ais Version of my lenses was optical better; Bokeh not perfect)
Nikon 105mm f/1.8 Ai-s (for me on 5D better than the 2.5 Version; Bokeh better...)
Nikon 50mm Ai-S 1.8 (my Version was bad on Canon)
Nikon 85mm 1.4 Ai-s (second best Portrait lens with Canon 5D MK 2)
Nikon 180mm 2.8 ED (Ai-S) (great Bokeh and great colors on 22 MP; for D850 perhaps not ideal without VR...)
AF Nikkor 180 mm 1:2,8D IF-ED (older Ai-s ED was optical better for me on 5D MK 2)
+++
Canon 85mm 1.2 II (better than all mentioned Nikkors; NOT better than the new Nikkor 105mm 1.4)
Zeiss Distagon 35mm 1.4 (better than all Nikkors)
Zeiss Milvus 35mm 1.4 (best manual 35mm; perfect Bokeh, Rendering and Sharpness; close-up limit 30cm therefore also great atmosheric images in the middle close-up range; great for portraits that include the living and working environment )
Zeiss Makroplanar 100mm 2.0 (ZE on Canon 22MP) for me better than all above mentioned Nikon Makros (Colors, Sharpness, Universality, 3D Effekt..., Bokeh etc.)
And yes - I also had a lot fun with searching the ultimative Film-developer-Kombination, which I never found...
Microdol, D-76, Perceptol, ... Ilford, Tri-X etc... Scanning...