The focus throw of the Voigtlander is very useful for manual focusing, but auto focus lenses have a distinct advantage in that focusing steps can be made very precisely via software and enable automation of the stack. Please refer to Rik's table below for some details.
Good point, if you're shooting in studio.
However, being soft wide-open makes the whole effort not so worthwhile.
Rik's table really only applies to 'most' lenses, not the CV 125.
You can't compare a standard, plastic lens (with a 'loose' 120-240 degree focus throw) to a precision macro lens with a smooth, first class 600+ degree focus throw. Apples and oranges as it gets.
(It's like comparing how a Toyota Corolla handles a mountain road to how a Porsche 911 handles it. The class/handling levels are worlds apart.)
The screw drive autofocus of the Nikkor 200 mm f/4 is not good for automation, and I have chosen the Sigma 180 mm f/2.8 instead and did not want to wait for Nikon to update their 200 mm lens.
Good choice. I'm pretty sure the Sigma 180 is the best of its kind IMO, much much sharper wide-open than its siblings. I've not tried to program stack it on a D850 but I am sure it is nice.
Sigma 180mm f/2.8
Sigma 150mm f/2.8
As you can see in Mr. Otoole's tests, and in Ephotozine's Imatest, the Sigma 150mm is quite dull wide-open, and barely achieves excellence stopped down, while the 180mm f/2.8 (not to be confused with the lesser f/3.5) is well passed excellent, even wide-open, with much better edge to edge sharpness as well. It may not be quite as 'well-corrected for CA in a white-paper/black letter test,' but it is a much
better, sharper lens overall.
Having used both, the CV 125 is even sharper wide-open, and the CV also has better micro-contrast, color rendering, and bokeh.
Also, for attempting to stack live subjects, with a precision focus ring you don't need to 'stop' and program a camera (or setup an automated rail) in the field.
With a Class A, precision focus ring you can just incrementally move your left thumb in smooth, ever so slight, incremental steps.
Even the Sigma 180 can't do this smoothly, or precisely, like the CV 125 can. (I can only explain the difference in 'feel' as Toyotas and Porsches again. They're both cars, but ...)
Have you ever tried to follow a butterfly moving from flower to flower, and get a short stack using camera software (or an automated rail)? Not much fun trying to program on a fleeting moment
In-camera software is good for static subjects or maybe dead or posed subjects, where you have the time to set it up. Not so much for real-time, fleeting moment stacks.