▁idea ▁behind ▁these ▁mount s ▁was ▁' one ▁l ens , ▁any ▁mount '. ▁A ▁ret ail er , ▁for ▁instance , ▁only ▁had ▁to ▁keep ▁one ▁l ens ▁model ▁and ▁a ▁few , ▁cheap ▁mount s , ▁rather ▁than ▁many ▁l enses ▁in ▁every ▁different ▁l ens ▁mount . ▁It ▁allowed ▁automatic ▁a pert ure , ▁a pert ure ▁indexing / meter ing ▁facilities . ▁ ▁Mount s ▁were ▁offered ▁in ▁almost ▁all ▁popular ▁f itt ings . ▁It ▁was ▁su pers eded ▁by ▁the ▁T X ▁system , ▁( though ▁the ▁T 4 ▁mount ▁was ▁compatible ▁with ▁T X ▁l enses .) ▁Viv itar ▁as ▁a ▁brand ▁name ▁was ▁owned ▁by ▁P onder ▁& ▁Best ▁at ▁this ▁time ▁( T 4 ▁for ▁Two ). ▁▁ ▁T 4 ▁inter change able ▁mount s ▁produced ▁for : ▁ ▁Can on ▁F L ▁( same ▁as ▁F D ) ▁ ▁Min olta ▁SR ▁( Us es ▁MC ▁and ▁MD ▁line ▁of ▁l enses ) ▁ ▁Mir anda ▁bay on et ▁( all ▁except ▁S ens ore x ) ▁ ▁Mir anda ▁S ens ore x ▁ ▁N ikon ▁F ▁- ▁Silver ▁or ▁black ▁ ▁Pent ax / P ra kt ica ▁universal ▁sc rew ▁( M 4 2 ) ▁ ▁Pet ri ▁ ▁Top con ▁RE ▁ ▁Kon ica ▁AR ▁ ▁References ▁ ▁External ▁links ▁▁▁▁ ▁Sol ig or ▁L ens ▁Comp end ium ▁ ▁Sol ig or ▁in ▁o ly p edia . de ▁( ext ensive ▁illustrated ▁article ▁in ▁German ) ▁