Originally posted by SylBer ... to use my DA*200 with extenion tubes. Should I expect decent results from this combinaison?
Depends on what you expect. There's no optics in rings to change the IQ but exposure compensation becomes a factor.
The problem with rings on a long tele lens is that it takes a looong extension to cause a true macro effect.
The general rule goes like this: e.g, a 100mm lens needs 100mm extension to go to 1:1, 50mm to go to 1:2, 25mm to go to 1:4, etc.
Having said that, I often successfully use 12 - 25mm of extension with a 200mm lens to reduce the minimum focus distance. Just take any sort of ring of 1/2 - 3/4 inch and hold it between the camera and lens to see if this will satisfy your need. If so, consider removing the optics from an AE-capable 2x TC for use as a ~25mm extension ring that preserves AE functions. The Tokina 2x works well and can be acquired for as little as $50 if you pay attention.
H2