This helicoid (16mm~26mm) in photo can allow for the lens to focus from 0.78m to
2.33m, so you cannot use for a general shooting. If you use the other smaller helicoid
of 12mm~19mm, you can focus from 1.46m as nearest point to inifinity, even though
this setting with the smaller helicoid is only for the landscape photography I think.
2006-Mar completed