A common question is why bother with old lenses when you can have a new lens. New is better, right?
Actually not always. Today’s lens coatings are superior in terms of durability, fungus resistance, and clarity compared to old lenses, but the glass is what makes the lens.
Older lenses were a bit toxic. Either from leaded glass or radioactivity, such as thorium. These additions to the glass increased the index of refraction and with lead, clarity. That’s why leaded crystal vases are so brilliant, and expensive. Today’s manufacturing techniques don’t allow these elements due to toxic dust that is formed during lens manufacturing. It is this vintage glass that gives the “look.”
The build quality of older lenses are also superior to today’s lenses. Many were made of brass with brass bearing surfaces and helicoils. Brass is a self-lubricating metal with excellent wear characteristics when compared to aluminum. This is what gives many of the older lenses the dampened focus feel.
Zoom lenses were not as popular in the past because simply there were too many compromises that had to be made with their construction. This is an area where computer design has really advanced optics. But for prime lenses, the old designs aren’t a whole lot different from today’s designs. That’s why the old Zeiss lens designs (Sonnar, Distagon, Planar, Tessar) are still used today.