milamber wrote:
There have been several threads lately about ND filters, largely following the series of superb landscapes posted. Plenty of advice about which manufacturer is best and why, but is there anywhere someone can point first time ND filter users like me at.

I'd like to take one with me travelling next week, but don't want to buy loads of different ones just yet until I have a go and see the results. I understand how they work and how many stops a given filter will reduce, but don't know what effect this would have in practice.

I was pretty poor at equations at school, but presumably there must be some equation that would let me work out the effect of the filter?

I was out early this morning in the mist. It was just getting light with the sun not up, but I still couldn't expose for longer than around half a second, even at f36.

How do I work out what exposure time I would have had with a given ND filter attached?

Ideally I would like to take just one with me, but don't know which would be most useful. Either that or get a Cokin set, but the reviews on those are variable. I can't justify a Lee set or similar at this stage.

The variable ones look convenient, but in my experience you usually pay for that in quality.

I should add that I am not all settled yet about which lenses I will end up keeping. I have a DA 18-250 and FA 50 for this trip, but that could easily change afterwards!

Any help appreciated.