Cinematography-Theory-And-Practice

NetsAnother form of diffusion is nets or voiles (a mesh that is coarserthan net). Many cinematographers use silk or nylon stocking material,which can have a very subtle and beautiful effect. Nets vary intheir diffusion effect according to how fine their weave is. Nets cancome in filter form sandwiched between two pieces of optical glass,or they might be loose pieces cut and attached to the front or rear ofand other tasks.Attaching a net to the rear of the lens has several advantages. Anet on the front of the lens can come slightly into focus with widerlenses that are stopped down. A net on the rear of this lens willnot do this. Also, the diffusion effect will not change as the lens isnet to the rear of the lens must be done with great caution as thereis danger of damaging the exposed rear element of the lens or ofinterfering with the spinning reflex mirror. Putting a net on the rearshould be done with easily removable material such as snot tape —Figure 13.9. Various grades of diffusion— the Schneider Black Frostseries. (Photo courtesy of SchneiderOptics.)image control257