Split ND Filters

[gregf]

<p>Currently I use a B&W Split ND filter, and am quite happy with it. In fact all my filters are B&W and I have no complaints.<br>

However, I remember years ago I also had Cokin filters for B&W and split ND. The obvious advantage for split ND was the ability to move the horizon. When I look at those old slides (mostly shot with my old 28-70 L lens), I don't see any degredation in IQ.<br>

<br /> However, I was wondering with new model digital cameras is there a loss of IQ by putting a cheap piece of plastic in front of your $1,500 lens? I've always used the B&W filters because the provide the least degredation to IQ, but what are your thoughts on Cokin?</p>

[David_Cavan]

<p>It can certainly be argued that putting anything in front of a lens will degrade the result, although every once in a while you see a post where someone has smashed the front of their lens and it is still taking photos that are indistinguishable from before the incident. But I do believe that there are some penalties. On the other hand, if you are faced with a grey/white sky that makes a photo otherwise pretty much untakeable, or the approaching sunset sky is brilliant while the ground is already dark, I think it makes sense to use a graduated ND filter. I carry them much of the time, and use them infrequently when it makes sense.</p>

[Marcus Ian]

<p>Of course they 'degrade' the <em>absolute</em> IQ. However, in certain situations, they allow you to <em>vastly</em> improve the <em>output --</em> despite that 'degradation'. Knowing when and how to do so? that's why we have photographers.</p>

[William Kahn]

<p>I agree with David and Marcus completely. I carry two Cokin ND Grad filters all the time, a 2-stop and a 4-stop. I normally dislike putting anything in front of the lens, but circumstances sometimes demand it. It's a tradeoff between some slight IQ loss with the filter versus a completely trashed shot without one.</p>

<p><a href="../photo/14347832">http://www.photo.net/photo/14347832</a></p>

<p>Incidentally, you'll see a lot of comments that Cokin filters aren't truly neutral density and produce a color cast. I have yet to see that happen. I think it's a kind of Nikon vs. Canon, or Leica vs. everything else thing... ;-)</p>

[david_henderson]

<p>I use graduated ND filters a lot; have done for years and believe that the degredation of image quality from the use of one clean filter with no major damage is theoretical not practical. </p>

<p>As far as you dilemma goes, I do not think that you help your decision by polarising the argument into B+W circular ( great product glass filter, but limited application) and Cokin ( cheapest "known" resin rectangular brand with wide applicability but doubts about whether they are as good as other brands made from similar materials. </p>

<p>A lot of photographers who use rectangular ND grad systems start with Cokin because they've been cheap and accessible, but move onto other brands because they want greater neutrality, less clumsy transitions, and a lesser tendency to scratch. You are more likely to achieve this with the more expensive HiTech and Lee filters. If you really do feel guilty about putting a cheap filter in front to an expensive lens, than buying Singh Ray filters will sort that out for you since they're a long way from cheap. You could even search out rectangular glass ND grads- make them and so do Formatt (HiTech) though mainly for the movie trade.</p>

<p>But cutting to the chase, a rectangular system is much more versatile than a screw-in filter where the horizon is always in the same place and the fade from ND to clear is always very gentle. I don't know any serious landscape photographer who doesn't make some use of ND grads or who worries very much about their effect of image quality. The thing you will find is that the filters do get scratched over time and that a lot of scratching can indeed reduce IQ. </p>

[sarah_fox]

<p>Gregory, if you're worried about image degradation from a plastic filter (which is always a possibility, depending on sun orientation etc.), consider the no-filter alternative to a spit or grad ND:</p>

<p>Version 1:</p>

<p>Using a tripod, take two exposures of your scene. Expose one properly for the sky and another properly for your foreground. Load both images into different layers in PS. Mask/erase parts of the top-most image to reveal the bottom-most image as desired. You can create a gradual transition such as a grad or split ND would create, or you can more selectively use your two layers for a more intelligent approach to dodging or burning. You can even cut sharp lines for instance at the horizon or have a fuzzy transition follow an irregular horizon. You can do it just about any way you wish.</p>

<p>Version 2:</p>

<p>Sometimes you can't take two identically framed exposures. In that case, you can open an image, duplicate the image into another layer, and contrast the two layers differently. Then you can manipulate them per Ver 1. Obviously your approach must be to expose so as not to clip the highlights and then later boost the brightness of one layers for the shadow detail. Thus part of your photo will be slightly underexposed. This is not a serious limitation when using a camera with a good sensor. Here's an example with several stops underexposure in the foreground, done with an old 10D:</p>

<p><img src="http://www.graphic-fusion.com/phsedonamountains1sm.jpg" alt="" /></p>

[dan_south]

I use graduated ND filters extensively. I started to worry recently about their impact on IQ, but some recent 48 inch prints from 5D Mark II

files shot through grads alleviated my fears completely.

 

I prefer the large 100 mm (Lee) size to help control vignetting with wider lenses. The Lee filter holder is robust and adjustable. My

favorite grad ND filters are made by the Singh Ray company (available in either Cokin or Lee size). The Singh Ray filters come in a

variety of useful configurations and add no artificial color casts to skies.

[sarah_fox]

<p>BTW, some of us have had this discussion before. In the end, I think we agreed that while my method was more precise and versatile, some still considered it a pain in the behind. I can't argue that my method is easier. It isn't.</p>

[David_Cavan]

<p>Sarah and William - great shots; both appear to be great outcomes. I tend to agree with you Sarah that your approach might create a better high-resolution outcome but as you say, there's a time penalty to be paid.</p>

[john_macpherson]

<p>I used Cokin ND for years but gave up. Ok for wideangle lenses but with teles the optical imperfections made the images unusable. A few had serious colour casts that rendered skies purple. Used Singh-Ray instead and no problems (other than scratches).</p>

[mendel_leisk]

<p>I <em>parked</em> a B+W rotatable ring filter style Graduated ND on my Canon 17-40 on a recent vacation. Very handy, useful in most shots.</p>

[martin-s]

<p>I haven't used my grads in quite a long time. The reason: the effect is permanently 'baked into' your RAW file. While that was fine in the film days, digital capture offers more options.</p>

<p>I prefer Sarah's approach #1. If you need to layer hand-held shots you can use PS's Auto Align Layers command to get them in registration and then hand-paint your layer mask.</p>

<p>Or I use <a href="http://www.dpreview.com/articles/1205103502/extreme-contrast-edits-in-lightroom-4-and-acr-7">LR4's new tools</a> to achieve a similar result from a single capture. The redesigned controls in LR allow you to darken the highlights and lift the shadows at the same time in ways not possible before. These are also available in the graduated filters and brushes, which helps to avoid one of the most annoying problem of real grads.</p>

[philip_wilson]

<p>Cokin work fine - there is a slight colour cast but this depends on the intensity of the grad used. Their 1 stop have minimal effect but their three stop has a slight pink / purple cast. On virtually all shots this colour cast is not noticeable as the colour change is slight and usually impacts just the sky.<br>

The square / rectangular filters work better than the screw on type as you can adjust the grad position and effect more easily. I personally tend to prefer working with grads as it allows hand held use more easily. It really is a personal preference and environment thing. If I have a tripod I find Sarah's approach (number 1) works well but often in the mountains carrying a tripod can be a pain and the light levels are two varied for the camera sensor so approach 2 does not always work. This is particularly the case when shooting sunsets with a lot of snow / ice in the shot. Even the 5DII cannot capture the full exposure range in this type of shot and you either need to bracket (which requires a tripod) or use a grad.</p>

[dan_south]

I like 'baked in' effects as long as I have baked in the correct blend of exposures. If an elk crosses a meadow, its position

In the frame is baked in. I don't see that as a problem as long as I've composed the shot properly.

 

I like single-shot exposures. I don't have any moral issues with blending multiple shots. It's more of a practical matter.

Conditions change from second to second. Clouds more very quickly across the sky. Sunrises and sunsets change

continually. Flowers blow in the breeze. Animals and birds and humans and vehicles move through the frame on

occasion. I might get only one shot with everything lined up properly, and that's if I'm lucky. Multiple shots might not be an option.

 

Even if I can capture multiple shots, I would rather shoot a series of complete shots and choose one from the series than toggle back and forth

between partial exposures where I can only use the sky from one shot and the foreground from another.

 

Also, I spend a lot of hours each week post processing already. I don't need to add the painting of layers to my

workload. In cases where that's the only way to get the shot, I'll do it. Grad filters give me single-exposure success

ninety-nine percent of the time. That translates to a lot of manual work saved in the long run.

[sarah_fox]

<blockquote>

<p>If an elk crosses a meadow, its position In the frame is baked in. I don't see that as a problem as long as I've composed the shot properly.</p>

</blockquote>

<p>...but be sure to use a moose filter. I hear it works equally well for elk. ;-)</p>

[dan_south]

Haha! That's brilliant, Sarah! I have a couple of Moose filters, but I have yet to try them on an elk.

 

Thanks for making my day!

 

:-)