Is the Series IV a true knife-edge focuser?
A. It sure is, but…. most users find that the new 300 line/inch ronchi screen will result in extremely sharp images and is easier to use than a knife edge. After using a ronchi screen, however, you may be curious to try our True-Knife Option which employs a true knife-edge. Real knife-edge focusing really is not for the uninitiated or faint of heart, but after practicing with a regular ronchi grating, you will know what to look for and become a whiz. Try one. You’ll like it. Click here for a short tutorial on knife edge focusing using our True Knife Option.
