This lens although cheep is somewhat legendary because of its 15 blade iris. It doesn’t produce the swirly bokeh of a Helios or a Trioplan but it does come close.
The Jupiter 9 is basically a copy of the Zeiss Sonar 85mm/f2. The Soviet Union started producing them in the 50s and they where produced in several versions. ( you may find silver and black versions, the original silver version is from the late 50s-60s. ) this one is later version ( black ) from the early 90s.
It is a manual lens and is used mainly for portraits because produces a specific softness that may be pleasing when working with portraits. It is a m42 lens meaning you would need an adapter to fit it on your camera. If you are a Nikon user then this lens will not focus to infinity without an additional optical adapter that uses a corrective glass.
It is needless to say that by using an additional corrective glass at the back of the lens will only degrade the image quality. Now, if you are a Canon user then you are lucky as this lens will focus to infinity and you would only need a simple M42 adapter to your Canon camera.
The focus ring is not as smooth as with modern lenses at least not on my version. It has a stronger resistance then I would prefer .
So, is it any good on modern digital cameras?
The softness it produces, the dreamy look and color reproduction on full frame cameras can be pleasing when shooting portraits. It can produce some amazing out of focus bubbles, rings and swirls.
It is inexpensive, you can get one on eBay for $100-$150, depending on the condition. ( always careful check the picture included in the description on eBay ) Also you can check the serial numbers on the lens where the first two numbers indicates the year it was made, 90xxx or 76xxx for example.
Cons: It doesn’t handle flare nicely, but if you like to include some flare in your images for whatever reason it can be an interesting experiment. You may need to buy a hood for this lens if using it in bright sunlight.
To go from the minimal focusing distance of 0.8mm to infinity you would have to turn the focus ring almost 300 degrees or so. This is important as this is not a fast shooter lens unless you are zone focusing.
The bottom line is: This lens is a great performer for the price, no other modern lens in this price range can compete with Jupiter 9 in the bokeh making department. If you can, get one you will not be disappointed.
Other lenses from the Jupiter class includes the Jupiter 11 135mm f/4, the Jupiter 11A 135mm f/4, and the Jupiter 21M 200mm f/4. you might want to check them out too.