With the Cokin Filter P342 Double Mask 1 you can expose the image in two parts so that you can combine two shots into one photo. The effect is achieved by taking two shots each with one filter from the Double Mask set. One filter covers the centre of the image, the other the surrounding area. This double exposure can be done by taking the shot and not transporting the film any further or by exposing the entire roll of film and then rewinding to its starting position and taking the shot with the second filter. It is best to measure the exposure without the filter attached to the camera. The Cokin P342 Double Mask 1 filter is recommended for use with wide-angle lenses with a focal length of 21 to 35mm.
The system comes in two sizes: #342 and #345, which has a larger center spot.
Characteristics
Combine two shots into one photo
For wide-angle lenses with focal lengths from 21 to 35mm