i dont whant to hurt you but, thats not even close to photorealism, a hammer head does not look like that, its made of metal and not specular stone, to get that aged look add rust, that sould be bryce5 if u use dof so why dont u use the soft shadows option? why dont u add a texture to the nails? perhaps there is one but to me they look flat grey= not photo real. and for one last thing if you did show the end of the plywood or the heriozon and then added some more dof it would be more "Real". and a smal trick could be to make it B/W and add grain.