Thanks, Dan. This is becoming confusing. FWIW, the lenses I have also have pins on the front which accomodate the filter holder, which sometimes includes heating elements to obviate moisture build-up.Originally Posted by Dan Fromm
I do not know what a collimating mount would be, unless it is the same pins.
To know that you found not significant problem by not using a filter is helpful. Me thinks we are on target... until another surprise arises.
Again, many thanks