Explain ND filters to me.

[ImDesigner]

I'm interested in composing some nice long exposures of my coast line during the day and for this I'll need an ND filter.

Is there a "go to" number of stops I should be looking for as an average? If for example, I want to take a 1 second exposure at 1/1000 then I need a 10 stop filter? If so, how much blur will I be looking at with a 1 second exposure? Do I need that many stops? I've read that a 6 stop filter would be a good one to go for as it still allows for a longer exposure whilst being light enough to see through in order to compose the shot with it on the lens. Is that good advice?

Are there any brands I should bank on or avoid?

[markmullen]

This should help http://www.markmullenphotography.co.uk/blog/2012/8...

[hoyin]

I am no pro photographer ... In fact I only just bought a ND 9 stop filter.

But I actually found you can compose the picture using live view and do your focusing there as well.

Here is one I took a couple of weeks ago - my first time trying it out.


Skaftafell National Park - Svartifoss waterfall by Ho Yin Ng, on Flickr

[budfox]

Given that you're going to be using a tripod you could whack the filter on after you've composed the shot.

[ImDesigner]

Right then, how many stops should I buy and what brand should I go for?

[markmullen]

My article explains how many stops you'll need.

From cheapest to dearest in extreme long exposure filters you've got

Welding Glass > Haida > Hitech Prostop IR > Lee Big Stopper

[ImDesigner]

Ok, I've got my head around these now and I want to go ahead a buy a 10 stop. What exactly would a higher priced ND filter offer me over one costing half as much?

[ImDesigner]

Also, I'm having issues finding a filter to fit my lens. Do I need to buy one specifically sized for my lens? I've seen plenty of larger ones and I've seen adapter rings. What's the point?

I can't seem to find any concise information out there so if someone can definitively point me in the right direction, that would be helpful.

I need a 10 stop ND to fit a 58mm fitting.

[ImDesigner]

Having researched further, should I just go for a 77mm (the only size available in the filter I want) and buy a step-up ring to fit it to my lens? If so, would I need different step-up rings to fits different lenses? As an example, if I were to go for a 58-77mm step-up for a 58mm fitment, would I need a 67-77mm step-up for a 67mm fitment?

[Simpo Two]

Yep. But one 77mm filter and various step-up rings would be cheaper than an entire filter for every size of lens.

Or you could just hold the filter in front while you take the photo... you'll be using a tripod anyway so will have at least one spare hand, or both if you use the self-timer.

[ImDesigner]

Sounds like a plan. I'll crack on and get this bought now then. Thanks for confirming.

[markmullen]

I would counsel against trying to hold a 10 stop filter against the lens without a filter, the chances of you holding it accurately enough to avoid light leaking around the sides during exposures which will run into minutes are about nil.

[ImDesigner]

I won't. I'll be using a step-up and a 77mm.

[markmullen]

Simpo suggested it.

[Simpo Two]

'Light leaking around the sides'? Granted I'm not a regular user of ND filters but are you not simply looking through a piece of tinted glass? It's not like leaving the back open on a film camera.

[markmullen]

With the length of exposures you're looking at any tiny amount of light leaking around the filter causes all sorts unpleasant effects that look like flare, hence slot in filters like the big stopper having a gasket to seal them.