there are all sorts of lenses. some are meant to be sharp and corrected and some are not. the ones that are not are usually soft focus lenses, which were made in the 1800s and into the 1900s some as pictorial lenses ( they diffused the image so if the user wanted to photograph romantic scenes, panterly scenes &c the softness would add to the quality ) some were sold as portrait lenses because they were fast, and with slow processes ( daguerreotype, wet plates, early dry plate &c ) you wanted as fast an exposure as possible. you’ve probably seen old photographs of people, and their eyes look kind of ghoul-like, its because they blinked during a long exposure, not because they were dead or possessed by evil spirits. there are a lot of old lens designs some of the oldest used in cameras were the wollaston meniscus lens and the achromatic doublet / french landscape lens, also called the acromatic meniscus lens.
you can check out an wiki article on it here https://en.wikipedia.org/wiki/History_of_photographic_lens_design
if you have an old box camera, a falling plate camera and other fun stuff, you might have removed the lens from it. you probably saw there was a “choke” that looked like a barrel with a hole cut into it infront of the lens that acted like a fstop. that lens might be an achromatic meniscus lens or a wollaston meniscus lens. if you ever tried to put it on another camera or your enlarger without the choke, you will have noticed that it is really hard to focus. daguerre and others noticed the same thing so they put the same sort of fstop in front. it brought things in focus.
over the years i have played around with modern lenses and made soft images with them. the modern lenses might have been a modern G or D nikon lens or an older tessar, or zukio or pentax lens, or something i took off another camera and put on a 4×5 camera as a taking lens. i have a variety of images, some made with soft focus lenses ( veritar, and maybe verito and meniscus lenses ) as well as these other modern lenses but i won’t tell you which one is which. if you can tell, that is great, i am sure if i was shown these images, in print form printed by a lab or in the dark by me i wouldn’t be able to tell which was which, and to be honest the only reason i know is because i remember taking them.