I'm in the process of documenting the firearms collection of a museum. I use my Canon EOS Rebel T1i and the Canon EF-S 60mm f/2.8 Macro USM lens for the smaller weapons, such as pistols. I'm shooting all pictures from a computer and it works great. I'm having a bit more trouble with the antique longarms, such as flintlock muskets with bayonets. These are long and thin objects, from 60 to 80" long. What lens and set-up would you have uses on a task like that in order to get the picture sharp from butt to muzzle? Here is an example of what I'm trying to accomplish. Only better, of course!