Here's a tip I was taught when shooting a rifle but it works equally well (for me anyway) when I need to hold a camera steady for a shot. It's all about how to hold your breath. Most people breathe in and then hold their breath while taking the shot. But this means you are putting your rib muscles under strain and could cause a bit of trembling. Try filling your lungs then breathing out about a third of the way, then stop breathing out while you take the shot. I find this useful for those times when a tripod/monopod isn't being used.

This lens was introduced in 1959 with the original Nikon F. I am not sure if it was also available for their rangefinder cameras.

It had an original Gauss design and the optical formula was similar to that of the Zeiss Sonnar lens. If memory does not fail multicoating began in 1973.

This excellent portrait lens, available today at reasonable prices, especially those made with single coating like mine was one of the first lenses to bring professional reputation to Nikon optics. Another lens that was spectacular in the 70's was the 80-200 f4.5 a lens well known for its sharpness at all apertures. This specific lens changed the reputation at the time of zoom lenses.

These three images were made using the 105 f2.5 Nikkor P of the late 60's with a Nikon D610. They show its sharpness.
I have used other lenses for portraits but I always come back to this one. It built a reputation as one of the sharpest lenses made for portrait photography. I guess today, after more than 40 years it is still true.