/ variable ND filters

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rallymania - on 30 Apr 2012
Having never used an ND filter I was thinking of getting a cheap and cheerful variable one to start with and to learn how / when to use one

there's two on amazon that fit the bill
http://www.amazon.co.uk/Hama-Variable-Neutral-Density-Filter/dp/B004ZLVL12/
http://www.amazon.co.uk/7dayshop-Lens-Filter-Variable-Neutral/dp/B004TQDL34/

was just wondering if
a) it's worth spending the money on a cheap variable one,
b) have you used either of these or would to recomend a different one

thanks

Al
Richard Carter - on 30 Apr 2012
In reply to rallymania:

Never used a variable ND before, I'd probably just get the cheapest.

If you're into ND filters.... A friend of mine just bought a piece of welding mask glass for 4 online and glued a step up ring to it. For less than 10 all in he has a 16stop ND filter! :-D
James Dunn - on 30 Apr 2012
In reply to rallymania: You can get cheaper ones on eBay, some might be from HK but mine arrived in about 10 days and was <10.

I've used mine a bit but no where near enough to justify getting a set of Lee Filters or anything like that. It's fun to play with low shutter speeds in broad daylight but not worth the investment into a quality set of filters for me personally.

I wouldn't recommend the welding glass as the ones I've used give off a pretty strong green hue which is quite difficult to get rid of if you are wanting natural looking shots. Might have just been the glass I used of course.

Hope that helps!
Blue Straggler - on 30 Apr 2012
In reply to Richard Carter:
> A friend of mine just bought a piece of welding mask glass for 4 online and glued a step up ring to it. For less than 10 all in he has a 16stop ND filter! :-D

Fantastic, that might give me more useability with the F717 in IR mode for daylight (its IR mode is a "night mode" forcing it to f/2.0 and a shutter speed of 1/60 or less, so it's often a bit harsh in daylight e.g. this horrendousness: http://www.flickr.com/photos/blue-straggler/6908513329/in/set-72157629398177783 Ha ha haa!
dixmarra - on 30 Apr 2012
Richard Carter - on 01 May 2012
In reply to James Dunn:

Yeah there was a bit of a strange colour cast (it's not exactly a Lee filter!) but nothing that we couldn't correct in photoshop pretty quickly.

In reply to Blue Straggler:

I think it might be a bit extreme at 16stops!
f/2.0, 1/60 & ISO 100 is overexposed by 4 stops if I point my camera out the window today :-P
Blue Straggler - on 01 May 2012
In reply to Richard Carter:
>
> In reply to Blue Straggler:
>
> I think it might be a bit extreme at 16stops!
> f/2.0, 1/60 & ISO 100 is overexposed by 4 stops if I point my camera out the window today :-P

Fair enough. I might get some anyway and generally arse around with it...the F717 will go SLOWER than 1/60 in "Night Mode" so I might be able to afford those 16 stops. Long exposure daytime digital IR, hmm

Blue Straggler - on 01 May 2012
In reply to Richard Carter:

Getting mine for 1.90 delivered :-)

Currently for daytime IR I use (on top of the IR filter obviously) a standard polariser plus a ratty ND filter and a light blue filter from a bargain drawer at Doug's market stall, probably knocking off about 5 stops in total and that is nowhere enough when out in the great outdoors on a nice day, so we shall see.

The glass I just ordered is said to be about 10 stops' worth rather than 16.
chrisprescott - on 01 May 2012
In reply to rallymania: Interested to know if anyone has used the Genus Variable ND Filter? Wanting to order one for video work.
Blue Straggler - on 02 May 2012
In reply to Blue Straggler:
> (In reply to Richard Carter)
> The glass I just ordered is said to be about 10 stops' worth rather than 16.

Blimey that arrived quickly!

Garbhanach - on 02 May 2012
In reply to rallymania: I thought there was something wrong with my Lee big stopper when I got it due to blue colour cast but appears thats how Lee make them, forum on flickr about it http://www.flickr.com/groups/1392676@N21/discuss/72157624977296705/

If you get a colour cast with any ND filter you buy set up an in camera WB preset and make any final adjustments in photoshop.
ben@f-stopimages - on 07 May 2012
In reply to rallymania: I recently bought a variable ND filter nd was hugely disappointed. Although it would reduce the light by a couple of stops, it didn't come anywhere close to reducing it as much as i thought it would. also at it's maximum setting it produces a dark cross through the picture. further to this it created serious vignette issues on a 17mm lens due to the thickness of the filter.

Maybe i'm asking too much from it but if you want to really slow down shutter speeds on bright days it's gotta be a Lee big stopper. Or some welding glass as others have suggested, I'd be keen to try that!

Cheers,

Ben
chrisprescott - on 07 May 2012
ben@f-stopimages - on 08 May 2012
In reply to chrisprescott: I think it was a Hama, about 65 so not one of the super cheap ones. it did have marks on it but the 'cross effect' started to creep in about half way through the rotation towards maximum setting. due to this the only usable effect did not make much difference to slowing the shutter speed.
Adam Long - on 08 May 2012
In reply to beneboy:

Variable ND filters are just two polarisers stacked. When aligned, they act as one polariser (ie 2 stop ND), when 'crossed' at 90 degrees they block most of the light. I doubt the more expensive versions have found a way round the basic physics but I may be wrong.

At 17mm (assuming FX) you're asking a lot to use any filter without vignetting, even expensive Lee set-ups will struggle. As with any polariser you will get uneven effects with super wideangles (wider than 28mm horizontal) - this produces banding in skies and the cross effect.

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