TAAB STANDARDWill TAAB Standard work with my lens? You can measure the fit of your lens by either using the Diameter or Circumference as a measurement. LENS DIAMETER 2. 00 (50MM) TO 2. 50 (64MM) If the diameter of your lens focus ring is within the rage of Minimum (A) and Maximum (B), your lens will work with TAAB STANDARD. LENS CIRCUMFERENCE 6. 25 (158MM) TO 7. 85 (200MM) You can also use a string to wrap around the lens focus ring to measure the circumference.