the Rokinon 85mm f/1.4 has become renown for its fantastic combination of sharpness, buttery smooth bokeh, well corrected lateral CA with a wide aperture of f/1.4 all for $269-$300 brand new.
the catch? It is manual focus and your digital camera will not record EXIF data nor be able to change the aperture on it, but thankfully it does have a nice aperture ring.
having played with many manual focus legacy lenses on my Olympus Four Thirds dSLR system and Micro Four Thirds system, this lens has become one of my favorites as it gives me almost identical imagery on these cameras as the fantastic, but expensive and larger Canon EF 135mm f/2.0L lens on a Canon 1D Mark III dSLR - a favorite combination of mine for making a subject pop and have the background dissolve into lovely smooth bokeh.
accurate manual focus can be difficult due to the narrow depth of field at f/1.4:
on a dSLR, one may find help in the AF-confirm mechanism if you bought an AF-confirm adapter to mount the lens although dSLR AF may not be as accurate as you need for this lens
accurate MF is relatively easy on mirrorless camera systems cameras, just activate magnified view (and with Olympus cameras, simultaneously activate image stabilisation to make it easier still to visualise) BUT be aware there is NO AF confirm for legacy MF lenses on mirrorless cameras
it is an awesome lens for the bokeh mad and for videographers.
also sold under the names Samyang, Bower and Vivitar.
combine this with the Olympus OM-D E-M5 camera with 5axis 5EV image stabilisation for stills (not in video mode yet) and magnified live view manual focus and you have an awesome combination which will be hard to beat at that medium telephoto field of view - that is, until the Olympus m.ZD 75mm f/1.8 lens comes out!
compared with Canon 135mm f/2.0L lens
Side by side: GH-1 with Rokinon 85mm on the left vs Canon 135mm f/2.0 on Canon 1D Mark III on the right (click on each to see larger version):
if you have a Canon dSLR, I would strongly suggest getting a Nikon mount then a Nikon F-Canon EOS adapter with AF confirm chip to make manual focus easier
if you have a Olympus Four Thirds dSLR system camera then you could get the Four Thirds version, or either of the Nikon versions and then get the AF-confirm chip Nikon to Four Thirds adapter which will give you the AF confirm option
if you have a Micro Four Thirds system or Sony NEX E-mount camera system camera, you can buy any mount and just get a cheap Ebay adapter for it - you will NOT need any AF confirm chip on the adapter, and indeed, AF confirm chip adapters will generally not work on a Panasonic camera.
full frame 85mm focal length lens
9 Elements in 7 Groups
close focus 1m
filter does not rotate on focus
filter size 72mm - note filter thread mount is plastic, I would keep a filter on it to prevent damage
78mm wide x 72mm long
comes with plastic large lens hood which does not always fit easily