Simon Howson
Screenwriter
- Joined
- Feb 19, 2004
- Messages
- 1,780
Yes, it is essentially just a semi circular piece of glass that is placed in front of the regular lens. The background object is focussed in the usual manner using the uncovered portion of the lens. The other side of the lens covered by the glass diopter element will focus closer to the lens due to, I guess, the refraction of the glass altering the focal plane for that side.
In the screen capture I gave, the boundaries of the diopter have been concealed by aligning them with the edges of the window frame on the right, and the corner of the room on the left.
The use of split diopters by directors like De Palma, Frankenheimer and Spielberg to me represents a re-adoption of the 1940s deep focus style. That is to say, directors became notable during the 1970s for deploying both extremes of shallow focus shots acheived using long lenses, but also deep focus techniques using wide-angle lenses, and split diopters.
Obviously film was much faster in the 70s, making it easier to generate deep focus effects. But productions would use less lighting than in the 1940s, hence the split diopter lens would be a useful tool to acheive deep focus, especially in anamorphic, without shooting at a rediculously high f-stop.
In the screen capture I gave, the boundaries of the diopter have been concealed by aligning them with the edges of the window frame on the right, and the corner of the room on the left.
The use of split diopters by directors like De Palma, Frankenheimer and Spielberg to me represents a re-adoption of the 1940s deep focus style. That is to say, directors became notable during the 1970s for deploying both extremes of shallow focus shots acheived using long lenses, but also deep focus techniques using wide-angle lenses, and split diopters.
Obviously film was much faster in the 70s, making it easier to generate deep focus effects. But productions would use less lighting than in the 1940s, hence the split diopter lens would be a useful tool to acheive deep focus, especially in anamorphic, without shooting at a rediculously high f-stop.