Compared with uncoated filters, coating can effectively reduce reflections, thereby reducing glare and ghosting effects. 

There is a front thread, allowing another filter to be installed in front of the black soft filter, as long as the caliber is the same 

1 has the strongest soft focus effect, and the haziness of the picture is the most obvious. It is recommended to use it when the contrast between light and shadow is large, or the highlight range is small. 1/2 has a stronger soft focus effect, and the haziness of the picture is more obvious. It is recommended to use it when the contrast between light and shadow is large, or in an environment with large contrast between light and shadow. 1/4 has a relatively light soft focus effect, a moderate soft focus range, and is more versatile. It is also suitable for environments with small contrast between light and shadow. 1/8 has the lightest soft focus effect, and sometimes it is not even obvious when there are few highlight areas. However, this most gentle soft focus also brings it the greatest applicability, and it works well in various light ratio environments. 

Black soft filters of different gears gradually soften the highlights in the picture, and the transition between light and dark will become softer. The larger the value, the stronger the softening effect. 

The outer diameters of different calibers will be different. You can stack filters. Just buy filters of the same caliber and stack them (for example: 58 black soft filter, then stack 58 ND filter)