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Photography Question 
Jnaneshwar Surabathula
 

GND filters


I use a Sigma 10-20mm wide angle lens for landscape photography. I was suggested to use a GND filter by some 'photography' buddies. I'd appreciate if anyone could throw more light on it and which one to go in for?


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3/5/2007 1:29:30 PM

 
David A. Bliss   Here are some links from a quick google search.


http://www.ethanmeleg.com/tip8.htm

http://en.wikipedia.org/wiki/Graduated_ND_filter

http://www.outdoorphotographer.com/content/2004/mar/light_extremes.shtml


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3/5/2007 4:21:01 PM

 
W.   
Hi Jnaneshwar,

the point of a GND filter in landscape photography is to fool the camera's light meter into metering for the foreground, while the sky's luminosity is gradually toned down, effectively reducing the stark contrast between the two to retain detail in both.

Cokin built their 'empire' on effect filter systems like that. They're still around too: http://www.cokin.com/.
(I've still got a complete system with about 25 of those filters lying around somewhere in the attic...).

However, in this digital age GND filters have largely been superceded by HDRI, High Dynamic Range Imaging. A process that, if skillfully applied, is vastly more versatile than GND filters could ever be.

http://en.wikipedia.org/wiki/HDRI

Have fun!


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3/5/2007 4:31:27 PM

 
Mike Rubin
BetterPhoto Member Since: 10/15/2004
  I would rather use a GND filter to take the shot than have to spend addional time in fornt of a PC. I enjoy photography more than creative PC skills. I might feel different if I had never shot film. The Cokin filter is sold as a Gray Grad, which is not a true Neutral Density. I think the only filter that cannot be duplicated by software is a CLP (Polarizer).
Enjoy whatever you do.


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3/5/2007 7:14:58 PM

 
Jnaneshwar Surabathula   Thanks guys for all the responses. I was going through the sites suggested and now I am trying to figure out which GND filter is suitable for me. There are GND filters in gray, blue, pink...and so on, but I am unable to decide b/w gray and blue as I understand that using a blue filter shows the image in tones of blue and a gray filter shows the image balanced with enhanced foreground and background. I hope I am talking sense.I need some help help here.
I am looking at something which could be used for different pictures-value for money in short. I appreciate all the suggestions/responses in advance.


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3/6/2007 1:04:26 PM

 
W.   
"value for money in short"

In short:
investing time and attention to acquiring editing skills is the cheapest and most effective option.

But if you insist on schlepping around gear and spending a lot of time setting it up and breaking it down in the field, then by all means get a graduated NEUTRAL grey density filter (that's what the "N" in GND stands for; not for nothing). From experience I can tell you It's applicable in many more situations than a grad blue is.

But in reality I doubt it will often leave your closet.

Good luck!


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3/6/2007 1:24:50 PM

 
David A. Bliss   Go with a neutral density filter. Don't worry about colored filters until you understand how to use the neutral ones.

I use GNDs, even with the digital camera. I have used PS to achieve the same results, but much prefer to get the shot right in camera. Neither technique is wrong, just a different workflow.

You will probably need more than one GND, but a 2 stop filter is a good starting point.

Take an exposure reading of the foreground (darker) area, then take an exposure reading of the sky (lighter) area. The difference between the two is the strength of filter you should use.


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3/6/2007 2:07:56 PM

 
Suzanne Colson
BetterPhoto Member Since: 7/31/2006
  I don't know if you are considering the Cokin ND filters, but be certain they work on the Sigma 10-20 without causing vignetting. I have the Sigma 15-30 and if I shoot at 15mm with just 1 Cokin P filter and the filter adapter designed for wide angle lenses I have problems. I believe the filter size on the Sigma 10-20mm is 77mm. The 15-30 is 82mm which might be part of the problem. Not sure, but just wanted you to research ahead of time just in case.


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3/6/2007 8:37:57 PM

 
Jnaneshwar Surabathula   Suzanne, thanks for the info. I think I have to be careful about it. Even with the Sigma 10-20mm lens there is vignetting. One way to get rid of it is to use a flash on the hotshoe. The built in flash is not sufficient for it.


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3/6/2007 9:40:14 PM

 
W.    "I have the Sigma 15-30 and if I shoot at 15mm with just 1 Cokin P filter and the filter adapter designed for wide angle lenses I have problems. [...] The 15-30 is 82mm which might be part of the problem."

Does a bear sht in the woods?


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3/7/2007 3:18:05 AM

 
Samuel Smith
BetterPhoto Member Since: 1/21/2004
  family site...


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3/7/2007 10:07:36 AM

 
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