Titanium shutter: same as the Nikon F,. except for the first 1000 samples (extremely rare, from sn 6400001 up to sn 6401000), which had a cloth curtain. On the Nikon F, shutter curtain travelled horizontally, and flash sync was limited to 1/60", while on the F2 it travelled vertically (and sync was upped to 1/125"). I'll have to dig out an F2 to make sure... [EDIT: it travels horizontally on the F and F2, on Nikkorex and F3 it travels vertically and it's similar to current venetian-type shutter ]

Bernard, I confirm that the shutter curtains were thin enough to be rolled up in spools at the sides of the frame. Second curtain would unroll to cover the frame at the appropriate time, and at shutter speeds below 1/60" the whole frame would be exposed to light.

As an added bonus, including here an excerpt from my own Nikon F Identification Scheme (my own research, which predates heavily -and adds a little something- on the top work by Richard DeStoutz)

Ciao from Massimo

indeed, the AF-S 105mm f/1.4 is a nice example of filed curvature. The mild decenterings and higher order aberrations mask things somewhat at f/1.4. stopped down it is quite clear, with the most clear perhaps at f/2.8: maximum micro contrast happens at the center at about 32mm front focus. At about 32mm back focus you find maximum micro contrast far out in the image field. The achievement for this lens design is that meridional and sagittal maps track almost perfectly, thus there is negligible astigmatism ! As the field curvature in object space goes towards the back far out in the image field, it is interesting to realized that the curvature of field at the sensor side is opposite, concave towards the lens. Because of the imaging ratio ~ sqrt(1000) it is that the 32mm in the object side translate to 32 micrometers at the sensor side.

It is also interesting to look again at the comparison of radial MTF traces, which I attached before.  The MTF from Nikon shows quite a dimple at the center. This means that the focus was chosen a bit to the backfocus side to even out MTF radially. MTF stays quite high nevertheless. Also the separation of meridional and sagittal in the Nikon MTF is symptomatic for minor residual astigmatism.

This and other things, like longitudinal color aberration, defocus control in MTF etc,  are discussed in the supplementary material linked in my opening post.

Quick snapshot of the better half while shooting under an old train bridge in the desert near Socorro, New Mexico, USA yesterday. The reflected light seemed right even in the harsh midday sunlight. Nikon Z7ii 105mm F4, ISO 64, 1/250s.

The camera inside looks like very cheap electronics. A lot of plastic, thin metal, self cutting screws that cuts into plastic etc. etc.
A F2 does not look that bad inside? :-)

Last image I shot today. Both with D850 and 105 1.4e. Marvellous combo. I still have minimalism as my most common way to get close to the subject, I think.