ND(Neutral Density)


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solarii

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#2
ND filters cut down the amount of light reaching the film/sensor without affecting the overall colour balance of the image.

Think of it as sun glasses for your camera. Don't be lazy... search the web. There are lots of detailed articles about where and when to use ND filters. Its not hard to understand.
 

#3
Yeah, try the library. plenty of good books on basic photography, which covers the use of filters. Lots of pictures too. Else do a search on the web, even this forum, cause this had been discussed many times before.
 

tunster

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#4
A practical example for you...

When you want to take long shutter shot in day light (say water fall to have silky effect), you will need the ND filter to slow down your shutter.
 

photobum

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#6
There is also something called digital ND filters plug-in which you can use in Photoshop.

Cheers!
 

photobum

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#8
shuy said:
photoshop can create the silky water effect?? that's amazing!
Did I mentioned silky water effect? I thought I wrote ND filter plug-in for Photoshop.

I never try doing silky water efffect so I am in no position to advise you on this. All I know is under the hands of very creative individuals, Photoshop can be a very powerful tool. I have seen my DI staff created water and fire effects from it.
 

#9
shuy said:
photoshop can create the silky water effect?? that's amazing!

You CAN'T get no picture you shoot to have that smooth silky effect with some ND PS plug-in. If you can do that, you don't even need to go take the shot of the water scene. Just use PS and draw it out with your artistic illustration skill.

The ony way you can photographically produce that silky water would be to shoot the water scene in slower speed and in the day time, in order to compensate for the bright light that will force your camera to set speed much too high to capture OR should I say to "produce" that nice silky smooth flow. To do so, then you would use a ND filter to cut down the overal lighting of the water scene so that you can capture the scene at a slower speed. It is like capturing a night scene shot where since the sky is darker you use a slower speed to capture the night scene with as much existing light source and at the same time, as a by result, you get to capture car lights streaking as a long bands of red or yellow tail or head lights along the road.
 

solarii

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#10
There's a limit to what photoshop can simulate, as what sammy888 said you can't get silky water effects with an ND filter plug-in.

In fact the only photographic filters PS can simulate realistically (and easily) are the colour filters.
 

shuy

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#11
oh ok, just as i thought.

just a quick question, ND filter merely cuts out light equally across the spectrum, n PS can only simulate ND with a still shot. wldnt that merely amount to reducing exposure?
 

foxtwo

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#12
photobum said:
There is also something called digital ND filters plug-in which you can use in Photoshop.

Cheers!
the problem with trying to apply ND filters in post process is that highlights that have been overexposed will NOT have details. No post process is going to be able to produce detail when none was recorded in the first place.

Digital ND plugin may be able reproduce some aspect of a ND filter, but it has its limitations and cannot fully replace a proper filter.
 

foxtwo

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#13
shuy said:
oh ok, just as i thought.

just a quick question, ND filter merely cuts out light equally across the spectrum, n PS can only simulate ND with a still shot. wldnt that merely amount to reducing exposure?
there are few 'quick' answers in photography.

if i may post back a qn to you. "What would happen when exposure is reduced?"
 

#14
shuy said:
oh ok, just as i thought.

just a quick question, ND filter merely cuts out light equally across the spectrum, n PS can only simulate ND with a still shot. wldnt that merely amount to reducing exposure?

Yup that is more or less right. ND is not more or less about reduce light. It is like Sunglasses for your camera as I once mentioned in a similar thread. There is nothing really special bout ND except that it reduce the overall light going into your camera and hitting the sensor or film. But the BY-Product of using the ND would be it brings light down low enough to let you take the picture with a slower shutter speed at the same apeture (for example f8) The water flowing in that silky smoothing motion is no more then just blurring taking place. This is the same as when you take a picture of a person running very fast. If you use a shutter speed that is slower then the movement of his limbs, that is what cause the blurring effect. Simple.
 

#15
foxtwo said:
the problem with trying to apply ND filters in post process is that highlights that have been overexposed will NOT have details. No post process is going to be able to produce detail when none was recorded in the first place.

Digital ND plugin may be able reproduce some aspect of a ND filter, but it has its limitations and cannot fully replace a proper filter.

Actually I hardly can think of a reason for having or paying for a ND filter plug-in!!! hahah and I am speaking as a designer who use PS! heheh.
 

foxtwo

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#16
sammy888 said:
Actually I hardly can think of a reason for having or paying for a ND filter plug-in!!! hahah and I am speaking as a designer who use PS! heheh.
have lah, i can think of 2.

lazy. misguided.
 

photobum

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#17
foxtwo said:
the problem with trying to apply ND filters in post process is that highlights that have been overexposed will NOT have details. No post process is going to be able to produce detail when none was recorded in the first place.

Digital ND plugin may be able reproduce some aspect of a ND filter, but it has its limitations and cannot fully replace a proper filter.
The digital ND filter plug-in that I use at my studio actually requires two images composed into one. One image exposed for the shadows and the other for the highlights. It has since replaced my Singh-Ray Galen Rowell Soft Step 2 f-stops ND filter

This is definitely not lazy or misguided.
 

photobum

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#18
sammy888 said:
Actually I hardly can think of a reason for having or paying for a ND filter plug-in!!! hahah and I am speaking as a designer who use PS! heheh.
Haha... The reasons are:
  1. I do not carry an ND filter with me all the time.
  2. My Singh-Ray Galen Rowell ND filter is so scratched up that I find it pointless and too expensive to replace (US$99 for a Cokin P size filter)
  3. A digital ND filter allows me to control the number of f-stops I want instead of buying 3 or 4 expensive filters. I can fine-tune my images with selections from 0.5 to 6 f-stops. (Yes, 12 f-stops in all! Name me an ND filter that can do this sort of fine-tuning.)
  4. It costs US$45. Just pay with a credit card and download. (File size is less than 3MB)
 

foxtwo

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#19
photobum said:
The digital ND filter plug-in that I use at my studio actually requires two images composed into one. One image exposed for the shadows and the other for the highlights. It has since replaced my Singh-Ray Galen Rowell Soft Step 2 f-stops ND filter

This is definitely not lazy or misguided.
Do all digital ND filters require a composite of 2 images? My intepretation is that the digital plugin is based on 1 single image. Obviously not so for the one that you are using.

Lazy. Misguided pple are the pple who have the impression that a ND filter plugin (by itself) is able to replace a proper ND filter when based on a single image. Were it based on 2 images then I would likely assume you know very well what is happening and thus not those said terms. When one chooses to do things digitally, then expect to spend some time in front of PS. And much more time when you are not a PS wizard.

OT: photobum, would you happen to know the web reference to the ND plugin that you are using? I'm curious to learn what's the difference in it versus a normal merging of different exposures.
 

photobum

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#20
foxtwo said:
photobum, would you happen to know the web reference to the ND plugin that you are using?
I will let you know once I find out from my boss. The software is his actually.

FYI, I am an Adobe Certified Photoshop Professional since 2002, so you can pretty much call me a wizard!
 

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