[wudtw]

Can Any Big Brothers tell me ??
Much Thanks.

G6 new user

[Philippe]

在強光下減慢快門

[micros]

http://www.thkphoto.com/products/hoya/oef-05.html
http://www.npc.org.hk/chi/article/basic/art11.php

[tam_dominic]

It is to simulate the ND filter function.
ND filter is to reduce light going into the film / sensor.

With ND filter you can set slower shutter speed and/or smaller aperture. eg from 1/1000 second down to 1/250 second
eg from F5.6 down to F11

Happy shooting !