▁film . ▁The ▁frame ▁counter ▁is ▁also ▁blocked , ▁thus ▁pres erving ▁the ▁correct ▁frame ▁count . ▁At ▁the ▁time , ▁most ▁cam eras ▁did ▁not ▁support ▁longer ▁expos ure ▁times ▁than ▁about ▁one ▁second , ▁without ▁having ▁to ▁use ▁the ▁bul b ▁setting . ▁Maybe ▁this ▁was ▁why ▁Can on ▁placed ▁a ▁red ▁LED ▁to ▁the ▁left ▁of ▁the ▁pent ap r ism , ▁and ▁had ▁the ▁LED ▁flash ing ▁as ▁long ▁as ▁the ▁electronic ▁sh utter ▁timer ▁was ▁running . ▁The ▁LED ▁was ▁also ▁used ▁for ▁battery ▁check . ▁ ▁The ▁foc using ▁screen ▁of ▁the ▁Can on ▁EF ▁cannot ▁be ▁replaced ▁by ▁the ▁user . ▁Early ▁models ▁feature ▁a ▁micro pr ism ▁circle , ▁the ▁later ▁a ▁split ▁image ▁screen ▁with ▁a ▁micro pr ism ▁ring ▁around ▁it . ▁Typ ical ▁of ▁the ▁era , ▁all ▁view find er ▁information ▁is ▁provided ▁by ▁mechanical ▁arrang ements , ▁which ▁are ▁project ed ▁into ▁the ▁view find er ▁by ▁opt ics ▁inside ▁the ▁camera ▁housing . ▁The ▁range ▁of ▁select able ▁sh utter ▁spe eds ▁are ▁always ▁visible ▁at ▁the ▁bottom ▁of ▁the ▁view find er , ▁with ▁a ▁fork ▁out lin ing ▁the ▁currently ▁selected ▁speed . ▁To ▁the ▁right ▁is ▁a ▁scale ▁with ▁the ▁a pert ure ▁setting , ▁where ▁a ▁need le ▁points ▁at ▁the ▁a pert ure ▁the ▁camera ' s ▁expos ure ▁meter ▁selects , ▁and ▁also ▁automatically ▁sets , ▁provided ▁the ▁F D ▁l ens ▁or ▁F D ▁new ▁l ens ▁is ▁set ▁to ▁the ▁green