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Old 13-05-2012, 08:11 PM
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Graduated ND Filters - Why I don't think they're the panacea

I was chastised (politely, I might add) for not using GND filters recently. I know there are a few GND aficionados on IIS, so what I'm about to say might be seen as a bit controversial!

I would like to show you an example of why I don't see GND filters as the only way to achieve a pleasing landscape shot that includes a dramatic sky, yet retains detail below the horizon.

On my recent trip to the Great Ocean Rd, I was faced with overcast skies, yielding a flat light with low contrast. This produced the first attached image (straight out of camera).

Manipulation of white balance and exposure yielded the second image.

I than added a "graduated filter" in lightroom and made the third image. This replicates what you might have expected if you had used a GND filter in front of the lens. Note that the apostles are quite dull.

I then "painted in some light" (using the Adjustment Brush) onto the apostles and produced the fourth image.

I believe this ultimate effect would have been impossible to achieve "in camera", unless you had a custom GND filter that had the appropriate "cutout" to permit light through for the apostles.

The histogram of the first image is entirely within the range of the histogram (no clipping of whites or blacks). I haven't tried to drag any detail out of the shadows or highlights. I've selectively lightened and darkened the image, just like a skilled darkroom worker would have done with dodging & burning under an enlarger (I've seen an expert doing this, and it was amazing to watch). I had the impression that photographers who manipulated images in the darkroom were held in high esteem - the first "post processors". Now that we have these tools easily available to us through software like Lightroom, some people seem pre-occupied about getting everything right "in camera".

Just my two cents worth!

DT
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Last edited by DavidTrap; 13-05-2012 at 08:14 PM. Reason: typo
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Old 13-05-2012, 08:26 PM
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David,

I've been doing the same sort of processing in LR myself, but I just bought a set of ND grads. I reckon that even with the dynamic range of a D800/D800E there will still be situations where an extra couple of stops of filtering on the sky will be handy. I certainly have felt that it would have helped on some of the shots I took with my D700...

Cheers,
Rick.
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Old 13-05-2012, 09:26 PM
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I was only joking.

I blend exposures myself.

H
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Old 14-05-2012, 03:31 AM
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iceman (Mike)
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Great post-processing example David!
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Old 14-05-2012, 05:52 AM
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Good post, David. Nothing controversial in there. What you're doing is exactly what most would do with that scene if shot with GND filters. You can't get it all perfect in camera with a horizon like that. Sure, if it's a dead flat horizon that you can exactly match up the filter. But for mountainous horizons, buildings, trees etc I would think most would dodge the parts projecting into the filter's influence, otherwise you end up with that noticeable darker section.
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Old 14-05-2012, 06:33 AM
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Well articulated,and educational,appreciate learning from this.

Lovely image with number 4,hope the weather is a little kinder on next trip.

cheers Chris
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Old 14-05-2012, 09:23 AM
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Thanks for the replies Gents - thought I might be opening a can on worms with this post - maybe not!

Rick - I agree to a point. The only time when I really had to bracket exposures to allow for blown out highlights was when shooting directly into the setting sun. I don't think a GND would have reduced the highlights enough to retain detail in both shadows and highlights. It might be a case for HDR (surely that will create some controversy!)

DT
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Old 14-05-2012, 09:51 AM
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David,

If you believe in ETTR then a grad ND filter will allow you to expose further to the right for the part of the scene that's not attenuated by the filter.

I'm still deciding if ETTR is a good thing or not. I have seen good arguments for and against. I should do some tests when my filters arrive!

Cheers,
Rick.
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Old 14-05-2012, 11:14 AM
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Yeah, HDR is complete and utter rubbish. Clown vomit filter.

Nowadays, at least in Canon's implementation of Exposure Simulation Live View, you can see /exactly/ what your exposure is going to look like.

Coupled with the depth of field preview button, precise filter placement/dithering, set your aperture, and play with exposure compensation while keeping an eye on the highlights and/or histogram, you get a perfect exposure.

Of course, it's always a good idea to bracket, just in case, and, for scenarios where's there's objects obscuring the horizon such as the image in the original post, so that you can carefully blend those objects in post.

However, that's the reason why soft-step filters were invented -- to deal with foreground objects, mountains and such.

H
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Old 14-05-2012, 11:58 AM
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Rick - ETTR was the mantra that was being taught at the workshop.

H - I used Live View a lot for composition, and the exposure simulation was quite good.

DT
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Old 14-05-2012, 12:52 PM
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gah, HDR is not clown vomit. HDR = good.
How people implement the tone mapping to get a picture that looks like disgusting neon clown garbage. But then again, that's how people use most filters.

though I've never enjoyed using graduated ND's, since the graduation is never where I need it at the time
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Old 14-05-2012, 01:12 PM
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Software is not smart. It doesn't know what the scene you were trying to capture looked like.

HDR (tone mapping) attempts to assign values to each pixel based upon input files and tries to blend the images together to present something that is palatable. Problem is, it doesn't work. This is coming from someone who was heavily invested in HDR. I look back at what I thought was hot at the time and want to claw my eyes out.

As an artistic filter it is fine, but as a means to an end, particularly as far as landscape photography is concerned, it simply doesn't work.

I don't know how things are nowadays, but, when I was hot for it four years ago, there were halos and saturation artifacts strewn throughout the images.

Blending exposures manually and using filters gives you, as the photographer and artist the ultimate control and the ability to present what you saw in your minds eye.

Just my opinion. Your mileage may vary.

H
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Old 14-05-2012, 02:26 PM
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HDR from multiple exposures is just assembling a file with a floating point value for each pixel, rather than an integer. The tone mapping then uses said floating point to assign a value between 0-255 by reducing the dynamic range. The trick is that last step whether you get good or garbage. Otherwise, a HDR file just contains more information than a normal pic.

While this isnt a particularly artistic image, its still a tonemapped image from a HDR file based on software back in 2005 (which is admittedly before the HDR craze and more back in the papers being shown at SIGGRAPH)
http://dl.dropbox.com/u/14210505/HDRGarden_1.jpg
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Old 14-05-2012, 03:14 PM
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That looks relatively normal.

However, how many exposures did it take to reach that result? By the time all those captures are made the light would have changed (think golden hour) and clouds would have moved, too! It's a bit impractical, would you agree?

I am aware of Dr. Paul Debevec's pioneering work in HDRI and global illumination (I was a 3D modeler/animator). Fiat Lux is what got me interested in HDR.

H
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Old 14-05-2012, 03:47 PM
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That was a 5 exposure shot with the images around the edge being derived 1EV stops.

And it was generated with Paul Debevecs HDRshop program. Used to work with 3d laser scanning so his work with light probe and tone maps was of interest to me as an avenue of removing shadows.
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Old 14-05-2012, 04:54 PM
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Great processing David An uneven horizon and/or a nightsky scape are areas where GND's really don't cut it.

on the HDR talk- I come across this Youtube vid a month or so ago and couldn't stop laughing http://youtu.be/GowjeJd64S4
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Old 14-05-2012, 05:09 PM
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Lol that's awesome.
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Old 14-05-2012, 05:14 PM
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Thanks Greg.

Fortunately HDR is becoming less relevant as the dynamic range of sensors increases.

DT
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Old 14-05-2012, 05:30 PM
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rofl, that video!

Cheers, Greg.

H
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Old 14-05-2012, 09:46 PM
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I've seen some wonderful images from guys here recently and like David, I mean no disrespect...........I guess I come from the "old school" where I had no in camera metering, I looked at the subject, the available light and the general environment.....set the aperture and speed, framed the shot and presto. If working with B&W I had the luxury and satisfaction of manipulating the processing to get a specific result.

I recently purchased a 40D (my first DSLR) to hang off my 'scope but while "playing around" with it I realised just how much I've traded knowledge and skill for convenience
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