The focus of {HEAD ~ the projection lens} 68 is located between the second aperture 65 b and {TAIL ~ the projection lens} 68 
The focus of { HEAD ~ the projection lens } 68 is located between the second aperture 65 b and { TAIL ~ the projection lens } 68
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH