In general the Zeiss glass usually does a couple things diffrent . One is contrast usually a little more and mostly warmer tones, also with contrast you will see a little saturation boost. So yes they will render diffrent out of the can. Resolving power some are great at it and some are not better than some of the good Nikons . Also you may see a little less aberrations in the glass. This is in general are they the magic bullet is the question. In the older days I would probably say yes here since I was a nut case on this. Today what I'm seeing out of these new G lenses I would come back to depends on the lenses in question. The Gs are very very good now. The Zeiss 21 will stand above the rest but after that it's a lens per lens basis. Not like the old days. I guess I'm saying here I would not get so hung up on having Zeiss glass. I'm giving Nikon a lot of credit here which coming from me is rare especcially from years past.
Could not have been said or explained better Guy! I agree, it really is on a case by case basis, not only what body the lenses will be used on (which can make a distinct difference) but also you intended use of a particular lens. Closer-up portrait? Landscape? Reportage? General All-rounder? This too would determine which lens in a particular focal length might best be suited for the job. Addtionally, it's not only the resolution and sharpness across the frame but as Guy pointed out, the "look" of each lens too.
Regarding the 35mm focal length on the D800...I cannot speak specifically to their use on that body , but have used and tested both the Zeiss 35mm f2 and Nikon 35mm f1.4 on a D700/D3s and commented earlier in post in this thread, a few posts above, about these two exceptional lenses. For distant landscape use, I personally would select the Zeiss, especially for its sharpness across the frame and ability to reolve details ...but for other types of photography, I would most definitely consider the Nikon, not only for it's speed, but it's "look" and at times prsents a slightly more delicate and appealing image for certain subjects, yet also has good central resolution which picks up steam as you stop down. The Zeiss 35mm f1.4 is a beast in terms of physical size and I've only heard exceptionally good things about it, but cannot personally comment since I haven't shot with it.
Hmmm, the choice between the Zeiss and Nikon is maybe a lot like ordering a hamburger...I'd really like both fries and onion rings, but know I can only have one....LOL!
Dave (D&A)