▁A ▁symbol ▁( or ▁green ▁on ▁older ▁l enses ). ▁The ▁largest ▁opening ▁the ▁used ▁l ens ▁is ▁capable ▁of ▁is ▁always ▁properly ▁shown , ▁by ▁sh ifting ▁the ▁whole ▁scale ▁up ▁or ▁down . ▁The ▁range ▁goes ▁from ▁ 1 . 2 ▁to ▁ 5 . 6 , ▁in ▁order ▁to ▁suit ▁l enses ▁from ▁the ▁Can on ▁F D ▁ 5 5 ▁mm ▁ 1 : 1 . 2 ▁ASP HER IC AL ▁S . S . C . ▁to ▁the ▁Can on ▁F D ▁ 3 0 0 ▁mm ▁ 1 : 5 . 6 ▁S . C . ▁The ▁smallest ▁a pert ure ▁is ▁not ▁adjust ed ▁for . ▁The ▁camera ▁always ▁displays ▁a pert ures ▁up ▁to ▁f / 2 2 , ▁but ▁with ▁a ▁red ▁line ▁down ▁to ▁f / 1 6 , ▁to ▁rem ind ▁the ▁user ▁that ▁some ▁l enses , ▁like ▁the ▁Can on ▁F D ▁ 5 0 ▁mm ▁ 1 : 1 . 4 ▁S . S . C . ▁has ▁its ▁smallest ▁a pert ure ▁at ▁f / 1 6 , ▁while ▁some , ▁like ▁the ▁Can on ▁F D ▁ 1 3 5 ▁mm ▁ 1 : 2 . 5 ▁S . C . ▁can ▁stop ▁down ▁to ▁f / 2 2 . ▁Later , ▁when ▁the ▁Can on ▁F D ▁new ▁l enses ▁became ▁available , ▁the ▁camera ▁couldn ' t ▁properly ▁represent ▁the ▁new ▁smallest ▁a pert ure , ▁like ▁f / 3 2 . ▁You ▁had ▁to