ND Filters - Stopping stray light

Nikonite

Nikonite

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Dez
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Hello, Quick question for the group.

Been thinking of buying some square ND filters (probably ND 4's or 8's) for a Cokin P filter holder i was given but I'm scratching my head at how to stop light from entering the lens between the holder and the adapter ring.

I'd assume this problem has been seen by many!:thinking:
 
Ive just ordered some of these from amazon. You need an adaptor ring to fit your lens, which is good, as if you change lens size, you only need to buy a new adaptor for around 6 quid
 
my big stopper has a gasket around the edge to block stray light getting in, also you should be putting the ND closest to the lens and also use the eyepiece cover switch / rubber bit on the strap to help as well
 
Nikonite said:
Hello, Quick question for the group.

Been thinking of buying some square ND filters (probably ND 4's or 8's) for a Cokin P filter holder i was given but I'm scratching my head at how to stop light from entering the lens between the holder and the adapter ring.

I'd assume this problem has been seen by many!:thinking:
Click to expand...

Do you mean ND or ND grads? ND4 is only two stops and ND8 only three, so either way you'd be okay without a sealing gasket with those. Six, eight or ten stops of ND is a different matter.
 
Yeah, I'm looking to probably get a few filters, not grads, maybe something that cuts out anything up to 10 stops. There seems to be a gap between the lens ring and the filter holder. Do the holders generally have a gasket then? Can I buy them separate?

Cheers
 
Nikonite said:
Yeah, I'm looking to probably get a few filters, not grads, maybe something that cuts out anything up to 10 stops. There seems to be a gap between the lens ring and the filter holder. Do the holders generally have a gasket then? Can I buy them separate?

Cheers
Click to expand...

No, only the extreme ten-stop NDs have a gasket, on the back of the filter rather than the holder, and you definitely need a light-tight seal with those.

If you're not getting grads, screw-in filters are better.
 
Cool thanks. I suppose screw on variable grads will have the same issues as polarising filters on wide angle lenses?
 
Nikonite said:
Cool thanks. I suppose screw on variable grads will have the same issues as polarising filters on wide angle lenses?
Click to expand...

Not sure what you mean by a variable grad. There's actually no such thing. And what polarising filter issues?
 
Sorry, i meant variable ND's the ones on ebay for a tenner.

I've read that circular polarising filters on a wide angle, possibly ultra wide angle lenses are no use as part of the "scene" would be left with light and dark patches as the PL couldn't cover the extreme angles.
 
Nikonite said:
Sorry, i meant variable ND's the ones on ebay for a tenner.

I've read that circular polarising filters on a wide angle, possibly ultra wide angle lenses are no use as part of the "scene" would be left with light and dark patches as the PL couldn't cover the extreme angles.
Click to expand...

I don't care for vari-NDs at all. The cheaper ones are dubious quality and they all suffer from a dark cross appearing across the image at higher densities.

Those who say polarisers are 'no use' on an ultra-wides are talking nonsense. It is true that sometimes you can get an unattractive patchiness to blue skies, but far from always and usually only when the sun is low. If you don't like it, rotate the filter to moderate, or just take it off - though you'll then lose the benefit of reduced reflections on leaves and foliage etc that makes landscape colours richer.
 
If memory serves the Cokin P holders have a thin slot nearest the lens that takes their polariser and lens caps. So there is no way to put a full thickness filter right up against the back of the holder.

As noted above this probably isn't an issue when you're talking about 2 or 3 stops but with this type of holder you're gonna have real problems with light leakage once you start trying to use much stronger NDs. Even the gaskets on these filters are unlikely to be thick enough to stop this.

Afraid it's a limitation of the design of the holder so you may want to start looking at a different system if this is going to be something you're pursing more often.
 
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