This little Lucas the Spider plushie is a favorite test subject for lenses. If I shoot at night, then I have some light sources in the background and I can get a sense for how the out of focus areas are represented by the lens.
I shot this with my Nikon D800E (ancient at this time) and a Voigtlander 90mm f/2.8 APO-Skopar lens I bought earlier this year. I really prefer legacy glass to modern glass for the older lenses’ character, including their flaws. They often render more interesting images in everything from color, to sharpness (or lack thereof), to background blur (bokeh in photo parlance). Their optical imperfections produce interesting effects that I often like.
The Voigtlander lenses are proving quite interesting and have a modern adaptation. They have a microchip interface to the digital cameras (my Nikons) that enables the camera’s CPU to read the lens settings and incorporate that data into exposure control and fill in the EXIF data in the image file.
I like the Voigtlander lenses enough that I think I will add to my collection of them. I suspect they will become commonly used on my Nikon film bodies.