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12-03-2014, 04:42 PM   #1
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Grad ND filter question

I get the concept behind graduated ND filters, and the effect they give. Here's what I don't understand: the "graduated" part of the filter is basically happening horizontally (unless you're holding it sideways, of course). That's all well and good if you're shooting a scene where the horizon is more or less flat. You can apply ND effect to the sky, and not to the ground, or ocean, or whatever. But what if the horizon is not...well, horizontal. Mountains, maybe, or trees, or anything poking up into the ND part of the filter. Will they be underexposed? Or not? Do you fix it in the darkroom or PP? Is there not enough difference to worry about?

12-03-2014, 05:00 PM   #2
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I only use them when the horizon is (almost) flat. If not you can tell the difference and the picture looks funny
12-03-2014, 05:01 PM   #3
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QuoteOriginally posted by Lenscap Quote
That's all well and good if you're shooting a scene where the horizon is more or less flat. You can apply ND effect to the sky, and not to the ground, or ocean, or whatever.
Yep.
QuoteOriginally posted by Lenscap Quote
But what if the horizon is not...well, horizontal. Mountains, maybe, or trees, or anything poking up into the ND part of the filter. Will they be underexposed?
Yep.
QuoteOriginally posted by Lenscap Quote
Do you fix it in the darkroom or PP?
Yes, with masking but if you are going to have to do that anyway I prefer to just bracket and blend in software.
QuoteOriginally posted by Lenscap Quote
Is there not enough difference to worry about?
Sometimes it just does not make much difference, it depends on the difference in brightness between the sky and the not sky, as well as the strength of the ND grad and whether it is hard or soft.

I use ND grads if there is a reasonably horizontal horizon. If there are rough mountains or other non-horizontal parts I just shoot it bracketed and combine in software.
12-03-2014, 05:06 PM   #4
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Also, just because the horizon is flat, it does not mean that you will place the filter correctly. It may look ok in the camera screen but once you look in the computer monitor you may realize that you may have placed it in such a way that the dark portion is too high or too low. Turning on Live View and then slowly moving the filter down into the filter holder works best. [Assuming you are using rectangular/square filters on a filter holder like Cokin etc]. It takes some practice to get even this right.

12-03-2014, 05:12 PM - 1 Like   #5
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QuoteOriginally posted by psychdoc Quote
Turning on Live View and then slowly moving the filter down into the filter holder works best. [Assuming you are using rectangular/square filters on a filter holder like Cokin etc]. It takes some practice to get even this right.
You can also use a bit of cardboard sized to fit or cover the filter with solid paper until you get it in the right place. Then remove the paper or replace the cardboard with the filter. It does take a bit of fiddling to get it right.
12-03-2014, 05:14 PM   #6
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A couple of tutorial-type comments. And as others note, you have a second option of bracketing/blending or, rather, minimal HDR. (Minimal, please!)

Using Graduated Neutral Density Filters
Understanding Graduated Neutral Density Filters
12-03-2014, 05:16 PM   #7
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Thanks. I don't even have PP software, and turning on live view for me is putting my eye to the VF on the ol' KX. Sounds like for me, a grad ND would only be useful when the horizon has the common decency to be horizontal.

Thanks for the info!
12-03-2014, 05:20 PM   #8
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+2. The GND is fine for level horizons or those with only a few trees or whatever. You can tilt the filter to accommodate a tilted horizon but still have the same problems with trees, hills and things sticking up into it. You can use the Photoshop or Lightroom brush option to "paint" the parts you don't want darkened back to however light you want them but in most cases it is just simpler to bracket and blend or do the graduated light filtering in post-processing.

There are some software options, like NIK Color EfX Pro that will do it all in post and have a brush option you can use to paint the ND effect only where you need it but you need the software. Since I learned to use that, I pretty much just leave the GND filter in the bag.

The filters that are difficult to replicate in post are ND filters to slow down the shutter for artistic blurring and the polarizing filter. Those I use a lot. Others, not so much.

12-03-2014, 07:18 PM   #9
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Anything poking into the ND part will be slightly underexposed. If you're expecting your grad ND filter to fix every problem for you, you're expecting a bit too much. They pretty much simulate the graduated exposure filters in Lightroom. The difference here is that you can preserve highlights or make sure the exposure isn't so off that you need to lighten/dark half the picture so much that you introduce artifacts. Try darkening a sky to polarizer-level depth in Lightroom; if there's clouds, the huge change in contrast will cause parts of them to show visible artifacts. It's this effect that you should look to eliminate with the ND filter.

They do help with that quite a bit. They don't make the image perfect but they make it a lot easier to fix than going without it.
12-03-2014, 07:46 PM   #10
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QuoteOriginally posted by psychdoc Quote
Turning on Live View and then slowly moving the filter down into the filter holder works best.
QuoteOriginally posted by jatrax Quote
You can also use a bit of cardboard sized to fit or cover the filter with solid paper until you get it in the right place. Then remove the paper or replace the cardboard with the filter. It does take a bit of fiddling to get it right.
I was watching Art Wolfe on television about a week ago and he was shooting landscapes in Patagonia with the grad hand-held. What a pro, eh?


Steve
12-03-2014, 08:47 PM   #11
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QuoteOriginally posted by stevebrot Quote
I was watching Art Wolfe on television about a week ago and he was shooting landscapes in Patagonia with the grad hand-held. What a pro, eh?
Shot next to a guy at the Woodburn area tulip festival last spring and he was doing the same. I've no idea how he made it work, but he seemed to know his business. I just shot 5 brackets.
12-03-2014, 09:10 PM   #12
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QuoteOriginally posted by stevebrot Quote
I was watching Art Wolfe on television about a week ago and he was shooting landscapes in Patagonia with the grad hand-held.
I have done that with a rectangular resin grad filter. Used to use it in a Cokin filter holder but that was just too much hassle so I dumped the holder and just hand held it. That works ok if the camera is on a tripod so you don't have to hold it in one hand and the filter in the other, which is a recipe for really unsharp photos.
12-03-2014, 10:03 PM   #13
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QuoteOriginally posted by abmj Quote
That works ok if the camera is on a tripod
Yes, Art Wolfe was working on tripod.


Steve
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