I use a Fotodiox adapter (with "dandelion" focus confirmation chip) to mount a Nikon-mount lens to my Canon, the Cosina Voigtlander 58mm f/1.4. It is truly a magical lens. The adapter needed some tweaking to tighten it, and that damaged my admittedly cheap jeweler's screwdriver!
The bokeh highlights via this little Voigtlander may not be quite as smooth as the very best "normal" lenses in terms of bokeh...although they're smooth enough for me...but oh that sharpness!! Other than the 50mm Zeiss Makro Planar (which is an f/2 maximum lens, not 1.4)...I do believe this Voigtlander may be the absolute sharpest ~50mm lens there is. I've only used it on my crop camera, but I doubt the IQ drops off much even on a full frame, to the corners. One other quirk is that it won't meter light very accurately on my camera, with the aperture closed down. But it's possible any lens would do the same, with a manual aperture ring...since the only way to mimic light metering with automatic lenses to compare, would be to try to hold down the "depth of field preview" button while light metering. I doubt many DSLR's can do that, if any...nor would you want to, obviously.
The corners on the crop sensor via this lens, wide open (at least at or near infinity focus) stay absolutely sharp...with essentially zero lateral CA...and a small to normal amount of longitudinal (bokeh) CA. And there's very little vignetting wide open, if any...which is astounding and unheard of, to me. The color and contrast are up there near or with some of the very best, as well. Certainly the Canon 85mm f/1.2 "magic canonball" had more vignetting at f/2.2 than this Voigtlander has at f/1.4, on my camera. That 85mm also wasn't as sharp anywhere near the wide aperture end. By f/5.6 the "canonball" was a bit sharper than the Voigtlander is at the same aperture. But that's a huge, heavy, motor-focus driven $2000 lens!
Not many people know or care about this Voigtlander "Nokton", but it's a pleasure to use. Obviously it is "only" manual focus, and manual aperture. The build and feel are identical to other Zeiss lenses I have rented...and at much lower cost. It was the Photozone.de resolution test that ultimately convinced me to try this lens. I will probably never sell it.
A wonderful lens indeed ! I love Voigtlanders. I don't have that one yet but I do have the (much cheaper) Voigtlander 50/1.8 and it's a gorgeous little lens, beautifully made and one of the best manual focusing rings I've ever used. I keep picking up an putting down the 90/3.5 ... it's only that f3.5 that is putting me off. I'll wait for the 125mm I think
There is a major difference between the VLs and the Contax Zeiss lenses though (I have 3 of those) .. the Zeiss lenses are much heavier. Not for the weak-wristed :eek!: The 28/2.8, whilst not the ultra-expensive Hollywood 2.0, is still a superb and incredibly sharp lens and is my #1 landscape lens bar none. It's incredible value for money at around $350.
As far as 'exotic' 50's go though my favourite bar none is the Cosina 55/1.2 .... a bokeh unlike any other lens out there, wonderful !
Three examples. The last one isn't in perfect focus (hand held 1/15 sec after a few of those !) but illustrates the wonderful treatment the Cosina gives to specular highlights.