1000x - filter only partially available

The good anticipate - The 8x and 64x filter are properly: sharpness, contrast and vignetting are very good. Unfortunately, it looks at the 1000x filter different. The vignetting is so far advanced that in the middle of the picture a bright circle is and the surrounding area has become dark.

With some losses I had expected, but not to this extent. Colors are distorted.
The only feature that is not deteriorated in the 1000s filter sharpness. It is virtually unchanged with the 64x or 8x filter (or not having a filter)