Under construction

I am not geared up for serious lens tests, just keep that in mind... Here goes -
As far as normal day to day photography goes, and as far as my non judging eyes can tell, the lens, optically is as good as the other Nikon primes that I own (the AF-D 50mm f/1.8 and a 35mm f/2.0). But of course that does not mean much, only that the lens isn't a total disaster.

I've took the time to prepare and print some resolution charts, took a few test shots at apertures of 3.5 and 8.0, and did the same with the AF-S DX NIKKOR 18-70mm f/3.5-4.5G IF-ED zoom lens (the one that came as a kit lens with the D70).
All tests done on the Nikon D70 body.
As you'll see below, resolution charts do reveal some slight differences between the lenses, that I could not notice while shooting the occasional landscape or other abstract photos.

I was trying to set the Nikon to 20mm (i.e. rotated the zoom ring just a little towards the longer focal ranges, however, the EXIF headers still indicate the shots were taken at a focal length of 18mm.
Voigtländer 20mm f/3.5 Color Skopar SL II
DSC_5731 - Voigtländer 20mm @ f/3.5
Voigtländer 20mm @ f/3.5
DSC_5729 - Voigtländer 20mm @ f/8.0
Voigtländer 20mm @ f/8.0
Nikon AF-S 18-80mm f/3.5-5.6G
DSC_5732 - Nikon 18-70mm @ 18mm f/3.5
Nikon 18-70mm @ 18mm f/3.5
Resolution: Nikon 18-70mm @ 18mm f/8.0
Nikon 18-70mm @ 18mm f/8.0

Sharpness test, f/3.5

sharpness f/3.5

Sharpness test, f/8.0

sharpness f/8.0

Resolution chart tests - conclusion

These tests are far from being accurate. I could not hold the charts 100% flat, and lighting was not optimal (used available light).
Yet, I think they do provide some basis for comparison, and it seems that, when corner sharpness is concern, the Voigtlander is somewhat inferior to the Nikon 18-70mm, set at 18mm.