I have spoken to many photographers and many of them are afraid that if they use Focus Stacking techniques to maximise the Depth Of Field (DOF) of their image, they could lose the "BOKEH" which they also desire.
In this post, I hope to clarify that the photographer can actually "customise" how much bokeh they actually want in their image.
In this 1st example, I actually wanted to only have the entire centre of the flower aka "disk" or "eye" of the flower to be tack sharp , yet the petals should be soft and become part of the Bokeh.
This is exactly what I tried to do with this Daisy flower but first I want to show you the image captured using the maximum aperture (f51) which my Nikkor 60mm micro f2.8 could provide based on the working distance to the flower.
Aperture at f51 , 60mm micro Nikkor , reference image to compare
At this aperture, the Depth Of Field available actually extends to the petals of the flower which was not what I actually wanted. I did try shallower apertures like f40, f32 , but the center of the Daisy now does not have sufficient DOF to be entirely in proper focus.
This following image shows the screenshot of the details of the centre of the Daisy at 100% magnification. You can see that the details are soft due to Diffraction.
Now by using the D850 Focus Shift feature with the appropriate settings, this is what I could achieve. The image was post processed to show the centre details of the Daisy, but you can also see that the petals are a lot "softer" in focus than the same daisy (image above) when captured with an aperture of f51.
Lens : 60mm micro Nikkor
No. of images stacked : 53
Focus Step Width : 5
Lens aperture set to f5.6
This following image now shows the screenshot of the details of the centre of the "Stacked" Daisy image at 100% magnification. You can already see from this screenshot that the details are significantly crisper.
Two more examples of how I can use Focus Stacking to get the desired areas of the flower crisply in focus yet have pleasing Bokeh to provide the appropriate separation between main subject versus background / foreground
Lens : 60mm micro Nikkor
No. of images stacked : 56
Focus Step Width : 3
Lens aperture set to f5.6
Lens : 60mm micro Nikkor
No. of images stacked : 60
Focus Step Width : 4
Lens aperture set to f4.0
Conclusions
1. One can be creative even when using Focus Shift to create stacked images. A Focus Stacked image is no more associated with total sharpness spread across the entire image.
2. Being able to use the shallower apertures like f4.0 , f5.6 or f8.0 (macro images) allows for potentially "softer" backgrounds in addition to getting the best image quality (without Diffraction) for the primary areas desired.
There is still so much more to experience & experiment with the Nikon D850's Focus Shift feature.