I was thinking of getting a couple nd filters - a 0.3 and a 0.6. I thought it would be easy to then stack the two in order to also be able to get a 0.9 level of nd.
Whats odd though is these filters that are 77mm (to fit my lens I plan to use them with) mention that their front filter thread size is 95mm. Uh, so I guess you can stack them as the second filter would then not be 95mm but 77mm? Seems odd, its 77mm at the 'back' where we screw it into the lens but somehow it grew almost 2 cm by the front?
Aha, so thats what the extra wide bit really means. I just thought it was skinnier to minimize vignetting on wide angle lenses. So, decisions decisions then. I need to be thinking 0.3 or 0.6 and not necessarily stacking them.
