I was not too impressed with the optical clarity of the Ziess scope I had.
I had two scopes that came with a rifle. One was a new 3-9 Ziess and the other was an old Austrian-made fixed 6x Kahles ZF-69. The Kahles was an had a steel tube and old style adjustments that you let you see the crosshair move around in the reticle.
The Ziess appeared to be an exellent scope, but then I dialed the Ziess down to 6x and then compared it side by side with the Kahles looking out over the lake. The image produced by the Ziess appeared to be more pale and hazy in comparison. This surprised me because even if German and Austrian lenses may be comparable, I would assume that the newer technology lense coatings developed over the years would have given an advantage to the new Ziess.
I do not know if this was caused by the fact that the Ziess is a more complicated mechanism and the image is going through more pieces of glass, or if the quality is just not there. I have heard that they are not all made in Germany anymore, but am unsure if this is true.