138mm filters have no threads, they are designed to drop into a filter adapter ring or a matte box
Description
The Tiffen 138mm Deep Yellow #15 is commonly used for a noticeable increase in contrast with black and white films. It is also used to increase the separation of clouds and sky in black and white photography. Especially useful for clear contrast between blue sky with clouds and foreground. Enhances landscapes, marine scenes and aerial photography with more dramatic effects than Yellow 8.