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#1009543 - 02/09/2011 15:04 Graduated Neutral Density (GND) filters
MC Thomas Offline
Weatherzone Addict

Registered: 06/12/2004
Posts: 1119
Loc: Melbourne
After doing some reading it sounds like I may need to buy some Graduated Neutral Density (GND) filters. Looking at some examples with and without the use of a filter, it is clear that in certain situations they really are very helpful.

Here is a photo that I took-


I suspect that this photo could have been much better with the use of an appropriate filter. As you can see, the foreground is clearly underexposed. Also some of the detail of the storm structure has been lost. It was truly an amazing scene and unfortunately I don't think that photo fully captures that.

My question is what GND filter/s would be appropriate for such a photo? I suspect the difficulty here would be if you darken (probably not the correct term) the top half of the photo, the structure of the storm itself would be even worse I think (?). Although the foreground could possibly be exposed correctly.

Thanks in advance for anybody willing to help. I know there are quite a few good photographers on this forum.


Edited by MC Thomas (02/09/2011 15:07)

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#1009556 - 02/09/2011 16:01 Re: Graduated Neutral Density (GND) filters [Re: MC Thomas]
DaveM Offline
Meteorological Motor Mouth

Registered: 21/05/2001
Posts: 10186
Loc: Bathurst NSW about 700 m asl
As you already know/suspect, a GND wouls allow the blown out highlights to be darker (and get detail back in it)as well as darken the bits of the cloud that WOULD in life have been very dark, whilst allowing the dark foreground to have a light level more expected by our brain.

Until digi cameras can handle such extreme contrast levels (dynamic range in digi speak) something along the lines of a GND is the best "on camera" option.

If I went for a GND I think i'd want at the very minimum a 2 stop effect and quite probably a 4 stop might be better - actually probably both.

Even for common landscape shots they would be very useful on regular occasions.

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#1009595 - 02/09/2011 22:45 Re: Graduated Neutral Density (GND) filters [Re: DaveM]
bigwilly Offline
Weatherzone Mod and Photog

Registered: 25/09/2002
Posts: 6543
Loc: Junee - just north of the 'Bid...
Yeah GNDs are critical for in-camera mastery of landscapes (you can always achieve the same thing in a digi by bracketing and PPing the two 'correct' images).

I have 1, 2 and 3 stop ND filters on a Lee filter system (labelled 0.3, 0.6 and 0.9).

Did you use a polariser filter on the above shot? If not that would have helped add definition and depth to the sky.
_________________________
YTD Rainfall = 281.0mm (Avg to March 117.0mm)
MTD rainfall March = 34.7mm(Avg 41.3mm)
February 2011 total = 203.9mm (Avg 37.8mm)
2010 Rainfall: 759.3mm (Annual Avg: 521.5mm)

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#1009597 - 02/09/2011 23:04 Re: Graduated Neutral Density (GND) filters [Re: bigwilly]
MC Thomas Offline
Weatherzone Addict

Registered: 06/12/2004
Posts: 1119
Loc: Melbourne
Thanks for your replies. I was only using a Hoya UV filter. Sounds like I have a few things to buy now. I actually quite like the photo above, just think it could be a bit better. Really want to improve my skill now. Opportunities to take photos like the one above are few and far between so when I am in the right place at the right time, I better be prepared!

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#1009661 - 03/09/2011 10:23 Re: Graduated Neutral Density (GND) filters [Re: MC Thomas]
DaveM Offline
Meteorological Motor Mouth

Registered: 21/05/2001
Posts: 10186
Loc: Bathurst NSW about 700 m asl
Well definitely get a Polariser as Willy suggested, it's a filter that you will find VERY useful in your landscape photography. A GND still better for extreme contrast but Polariser does a different but equally useful job re glare on surfaces and enriching colours.

I use a polariser on almost all of my outdoor shots.


Edited by DaveM (03/09/2011 10:23)

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#1009675 - 03/09/2011 11:47 Re: Graduated Neutral Density (GND) filters [Re: DaveM]
thomo Offline
Weatherzone Addict

Registered: 06/12/2005
Posts: 2639
Loc: West End, Townsville, QLD
Not a big fan of sticking filters on quality glass, sort of defeats the purpose of getting good glass by putting less quality filters on.

Put your camera in manual mode and work on getting your exposure right.
_________________________
Westend - 0mm MTD - 256mm YTD
Severe Weather Chasers

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#1009692 - 03/09/2011 12:46 Re: Graduated Neutral Density (GND) filters [Re: thomo]
bigwilly Offline
Weatherzone Mod and Photog

Registered: 25/09/2002
Posts: 6543
Loc: Junee - just north of the 'Bid...
Nothing can really compare (in terms of nailing exposure or post-processing) to the effect a polariser has on your photos. Sure NDs can be replicated back on the computer by blending differently exposed images, but that can equally introduce artifacts and reduce overall image quality. And if the dynamic range of your scene is beyond the capabilities of the camera, you can fiddle with exposure all you like but you'll never get both the highlights and shadows in detail.

If you buy quality filters and look after them then they'll do little to detract from the quality of your glass.
_________________________
YTD Rainfall = 281.0mm (Avg to March 117.0mm)
MTD rainfall March = 34.7mm(Avg 41.3mm)
February 2011 total = 203.9mm (Avg 37.8mm)
2010 Rainfall: 759.3mm (Annual Avg: 521.5mm)

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#1009928 - 04/09/2011 12:58 Re: Graduated Neutral Density (GND) filters [Re: MC Thomas]
Harry Spotter Offline
Weatherzone Addict

Registered: 14/11/2001
Posts: 1955
Loc: Springwood, Brisbane
Yup, what they said! I wouldn't stress too much about "quality of glass" etc (sorry Thomo!). Composition and exposure will have a million times more of an effect on your shots than quality of glass (unless perhaps you're viewing a huge enlargement at close range). I'd rather a great exposure with a cheap lens, then a bad exposure with brilliant lens any day.

A necessary requirement of combining two images of different exposures later in post is a tripod - to make sure the two shots align later. Sometimes we don't have time to set up a tripod (especially during storm chases) so GND filters are awesome in this case. Although sometimes if the contrast isn't too high, there is enough detail in both the shadows and highlights of just ONE image to 'create' two shots to combine later (something I do often actually).

Having said that, most of my cloud shots are taken with a GND filter.



I had a tweak MC Thomas of your shot and it was able to be improved a little, but there wasn't much chance of bring detail back from those shadows. (I'm afraid I couldn't resist warming the tones up a little too - my weakness.) Photoshop's SHADOWS & HIGHLIGHTS is your friend! (Image > Adjustments > Shadows/Highlights)



One small note about polarising filters. I love them, but they don't darken the entire blue sky equally - they work strongest at 90 to the sun, then their effect lessens the further you drift from that 90. This effect is unfortunately often visible as a dark 'band' (rather than an entirely dark sky) when polarisers are used on very wide angle lenses like Canon's 10-22mm that I love so dearly. When shooting ultra wide, I tend to prefer a GND filter than a polariser. But you can also use this to your advantage: shooting at midday with a polariser when the sun is high means the darkest part of your blue sky is the horizon.. which may or may not look better in your shot. But at least knowing where the sky will appear darkest in relation to the sun will allow YOU to choose how you want to use the effect.

Cheers,
Marty.
_________________________
www.MartyPhotography.com.au

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#1009999 - 04/09/2011 21:56 Re: Graduated Neutral Density (GND) filters [Re: Harry Spotter]
Gustfront PD Offline
Weather Freak

Registered: 03/12/2010
Posts: 131
Loc: Sunshinecoast, QLD
(no expertise on my behalf as I havn't even upgraded to good glass yet) but for quick on the run cloud & sky shots I've tended to use polarisers & only recently started playing round with GND filters and right conditions certainly see benefits in their use.
On a side note does anyone still use linear polarisers? as circular polarisers seem to have limitations in certain light conditions. (apparently linears muck up auto focus on digitals) Just I think they had to manufacture the last linear I tried getting, especialy for me, took about 6 weeks to get in, & then it was the wrong one.. still waiting.
Cheers
Paul D
_________________________
Youtube :- Gustfront

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#1012427 - 15/09/2011 23:29 Re: Graduated Neutral Density (GND) filters [Re: Gustfront PD]
MC Thomas Offline
Weatherzone Addict

Registered: 06/12/2004
Posts: 1119
Loc: Melbourne
Lots of great info here. Thanks for everyone's input.

What about neutral density filters? I suspect these are generally not as useful for storm photography. However, I was wondering if it's possible in low-light situations to really get the shutter speed longer (like several seconds) to attempt day time lightning shots. I know you can use your relexes or a lightning trigger but I believe both of these approaches miss the branching and only capture the main channel. The branching is what really makes a lightning shot in my opinion. Just an idea.

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