195mm usually means a 45mm parfocal distance (that’s what I usually use) plus a 150mm sensor-to-image distance (which means 160mm “tube length”). As @WilliamW says, I wouldn’t expect the infinity sign. Usually infinity-corrected objectives are more expensive, so you may have gotten a good deal! Use William’s suggestion of the right optics module and base, and you should be good to go 
The image is pretty much always a disc, but the disc is bigger than the camera’s rectangular sensor so it should all work out fine.