Originally Posted by Dan Fromm
TYPO ALERT: For "anastigmat" read "Aplanat". I'll fix it in my original post too - thanks for noticing!
As to "standardised threads": This was a result of a standardisation of barrel diameters, whch was fairly easy in the UK since there were only two or three barrel makers supplying all the opticians. But out of the old British lenses I have, only one has one of these "standard threads".