f7f18077_r_PlayStation_3___GameRankings__Unlockable
[How to Unlock] Digital Camera [Unlockable] 
In the Nomad vehicle during the mission intermission; you can unlock a special photo by picking up this item in stage 4 instead of earlier
Metal Gear Solid 4: Guns of the Patriots Cheats, Codes, and Secrets for PlayStation 3 - GameRankings