▁a ▁very ▁fast ▁ 1 / 5 0 0 ▁flash ▁sync , ▁useful ▁for ▁day time ▁fill - flash . ▁This ▁comp ares ▁to ▁the ▁typical ▁ 1 / 2 0 0 ▁sync ▁speed ▁of ▁other ▁entry ▁level ▁and ▁even ▁some ▁semi - pro ▁D SL R ▁cam eras ▁such ▁as ▁the ▁Can on ▁E OS ▁ 4 0 D ▁with ▁its ▁ 1 / 2 5 0 ▁sync ▁speed . ▁ ▁Due ▁to ▁its ▁hy brid ▁electronic / me chan ical ▁sh utter , ▁it ▁is ▁in ▁fact ▁possible ▁to ▁flash ▁sync ▁the ▁D 4 0 ▁beyond ▁its ▁published ▁ 1 / 5 0 0 ▁maximum ▁sync ▁speed ▁up ▁to ▁its ▁maximum ▁sh utter ▁speed ▁of ▁ 1 / 4 0 0 0 . ▁The ▁D 4 0 x ▁does ▁not ▁share ▁this ▁ability . ▁ ▁The ▁D 4 0 ▁la cks ▁a ▁built - in ▁aut of ocus ▁motor , ▁which ▁means ▁that ▁only ▁N ikon ▁l enses ▁designated ▁with ▁AF - I , ▁AF - S ▁or ▁compatible ▁focus ▁mot ors ▁can ▁be ▁used ▁in ▁aut of ocus ▁mode . ▁ ▁Re ception ▁The ▁N ikon ▁D 4 0 ▁was ▁tested ▁by ▁various ▁independent ▁review ers , ▁receiving ▁generally ▁very ▁favor able ▁comments ▁for ▁its ▁erg onom ics ▁and ▁image ▁quality . ▁ ▁It ▁received ▁some ▁criticism ▁for ▁some ▁of ▁the ▁comprom ises ▁its ▁design ers ▁made ▁to ▁keep ▁the ▁D 4 0 ' s ▁price ▁and ▁size ▁compet itive . ▁For ▁example , ▁Digital ▁Phot ography ▁Review , ▁among