Filter

I have recently purchased an Olympus 35SP rangefinder, and it has come with a filter fitted to the lens. The filter is marked SL-C. What type of filter is this and would I need to make any adjustments to the settings. The light meter is on the camera body, not the lens barrel.

I've never heard of an SL-C filter. Can you describe what the color of it is? Do colors show up looking thru it (in the case of a filter for color film), or is everything monochrome, the same color as the filter (in the case of a filter for B&W film)?

To tell how much to adjust your exposure for it, take the filter off the lens and hold it over the light meter. However much it moves is how much you need to compensate your exposure.