I had no idea that lenses could have such an impact on colors and contrast vs resolution. If it's germane to the thread could you talk more about that?
Sure they do. If I look side by side shots from a Canon 40/2.8 and a Voigtlander 40/2 at f/2.8 the Voigtlander has more contrast and saturated colour plus a bit of vignetting which makes things look like they pop more. The Canon is more flat. A kit zoom lens will be low contrast and not so saturated vs one of the top top end zooms or primes. This stuff is easily visible, particularly when using digi.
I have used the modern Zeiss 50/1.4 and 35/2 (ZF version for Nikon) and I now have a Leica 50/2R and 35/2R for my R8. I did not have them at the same time to do comparisons but looking at photos (and I have not shot that much with the Leicas as I've only had them for a short while) the overall feel is that the Zeiss had more contrast and bite. The Leicas seem to have a gentler rendering, particularly when looking at portraits, yet retain sharpness. The Zeiss 35/2 in particular verged on the harsh, a landscape with trees/grass would almost like you over-sharpened the photo in photoshop. It has a distinct look. The Zeiss 50 was amazingly sharp by f/2 with very fine detail showing in the shots and high contrast. The 50 Summicron shows all that detail but keeps things a bit easier in the eye, my wife says it makes her look 10 years younger which is fine by me as it is my excuse for buying more of this stuff!
It is down to taste and you get to recognise it after many many shots as an overall look. You wouldn't see it if I showed you one shot from each, you just get a feel for it after looking roll after roll shot with a lens.
Sharpness is just one characteristic of a lens and once it has sufficient resolution then the rest of the features take over. Unfortunately most people in the digital era just zoom at 100% and check sharpness while overlooking everything else that is more important to the overall image. Besides they think they can correct everything like colour and contrast in photoshop...oh well.
