In Guide to Leica added to the review of the Leica 16-18-21mm f/4 Tri-Elmar-M ASPH are several new and/or revised pages:
- Field of View at 16mm, 18mm, 21mm. Includes comparison to 18/3.8 SEM and 21/3.4 SEM as well as two 16/18/21mm series on the Tri-Elmar to show the range.
- Distortion at 16mm, 18mm, 21mm along with examples of corrected and uncorrected images.
- MTF discussion overall as well as specific comparative 18mm MTF and comparative 21mm MTF pages comparing to the 18/3.8 SEM and 21/3.4 SEM.