BirdForum is the net's largest birding community dedicated to wild birds and birding, and is absolutely FREE!

Register for an account to take part in lively discussions in the forum, post your pictures in the gallery and more.

Reply to thread

Message: <blockquote data-quote="Dr Owl" data-source="post: 3183921" data-attributes="member: 130540">If he is a keen user of neutral-density filters, Binastro, he may have better filters than you realize.Many landscape photographers nowadays use Black Glass filters, which allow only one-thousandth of the light to pass.  In photography-speak, these are known as 10-stop filters (log to base 2) of optical density 3.0 (log to base 10).Passing only one-hundred-thousandth of the light (am I right in thinking that is the opacity of welder's glass 13?) requires an optical density of 5.0, which could be achieved by stacking Black Glass with routine 6-stop (density 1.8) and 1-stop (density 0.3) filters.Wouldn't that be enough to protect his film/sensor?Later,Dr Owl----------------------------------John Owlett, Southampton, UK</blockquote>