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Introduction

This Guide explains and demonstrate the use of extreme neutral density filters, with particular focus (groan) on the Hoya 9-stop ND x400 Filter, the Lee “Big Stopper” 10-stop ND Filter, and the 10-stop B+W #110 ND Filter, with some discussion of neutral density filters in general.

There has been a world-wide shortage of those particular filters as they’ve gained popularity with DSLR users, with Hoya, Lee and B+W being caught out by the sudden upsurge in demand. I attribute a chunk of the cause to the popularisation of their usage by such websites as Redbubble and Flickr, and magazines, particularly the UK’s Digital SLR Photography.

I have included at the end of this Guide a Resource List, including a rough price guide. If shopping on-line, be aware that prices vary significantly, especially in Australia, so caveat emptor rules, ok? Since originally uploading this Guide, it has become apparent that supplies are forthcoming, but in dribs and drabs. This appears to be universal.

I want to be upfront and say I am not recommending one over the other of anything. I have and use neutral density filters made by four different companies, and I do not get any commissions or kickbacks. However, in my Resource List I do discuss one particular type of neutral density filter, unique to a particular manufacturer, which, to say the least, is almost useless. Considering it costs between 250% and 300% more than others, this is rather disappointing. I should have believed the photographer I met on Big Nobby at Crescent Head instead of placing faith in the testimonials on the company’s website. I am talking about the Singh-Ray Vari-ND filter.

I have also been buying gear from one particular Australian supplier in Sydney whose prices and service I have not yet seen bettered, and because that is the plain and simple truth of my experience (yours may be different), I tell you who that is, also in my Resource List. Since originally publishing this Guide on 6 January 2010, I have been informed of 2 Melbourne suppliers who can supply the ND x400 slightly cheaper, on order with some in stock – Refer to the Resource List.

Please note that it was my intention to maintain this particular tutorial with irregular updates and expansions, and this has occurred. I list all updates at the end of this Guide. If you have any questions or technical queries about the content of this Guide, please do not hesitate to contact me at peter_h111@msn.com. I ask this because any comment attempting to point out errors will be deleted – this is my publication not yours. Email me instead your issue and I will respond, and if necessary I will take your issue into account when next updating the Guide. If you found this Guide via Google and want to see more examples of my photographic work with ND and Grad ND Filters, check it out here.

Please note that, apart from the images of others used here with permission, the content of this guide is subject to copyright, which is held by me. All rights reserved.

Contents

Terms used in this Guide What is a Neutral Density Filter? What is a Grad ND Filter? Some history What’s the big deal with the Black Glass? Eight different uses of the BG are explored and demonstrated How to use a Black Glass – Discussion and tips on gear, effect of wind, taking the shot, ND and UV filters, stacking, hot pixels, and using small apertures How to use a Big Stopper – A look at Lee’s 10-stop glass ND filter The Big Stopper versus the B+W 10-stop ND Filter – Colour casting – They’re not the same The Hoya 82mm ND x400 Filter Does it stack up? Those who inspire – I name names – the giants of RB Resources – The where’s and the what’s

Terms used

You may have seen the term Black Glass used on Redbubble. The person who first coined it was Adriana Glackin. It was March 2009, and Adriana and Tatiana (the 2 Yarners – think about it) and myself were at the very bottom of Wentworth Falls in the Blue Mountains of New South Wales. Adriana asked Tatiana if she could try using her “black glass thingy”. She was referring to Tatiana’s Hoya ND x400 filter, but the name is rather appropriate so it stuck. After all, this what the ND x400 looks like:

Rather dark, isn’t it?!

In this Guide, I use the following terms:

Black Glass or BG to refer to both the 9-stop Hoya and the 10-stop B+W. (I should also point out that it was Tatiana who turned me onto the creative uses of the BG.) Big Stopper or BS to refer to the 10-stop Lee ND Filter

Other terms you need to be familiar with, if not already, are:

B&H – A major photographic gear supplier, based in the USA. (See further the B&H links to ND filters in the Resource List. B+W – A division of Schneider and a brand of BG. Btw, B+W does not stand for Black & White. Two guys, Herr Biermann and Herr Weber, started the B+W partnership in Berlin in 1947, and the business was taken over by Schneider in 1985 who retained the B+W brand. CP – Circular Polariser, a type of “screw-on” filter. DOF – Depth of Field. ND – Neutral Density. Grad ND – Gradual Neutral Density, including Soft Grad ND and Hard Grad ND. AWB – Auto White Balance.

What is a Neutral Density Filter?

An ND filter is to a camera lens what a pair of sunglasses is to a human. (Peter Hill, 2010.)

No more, no less. It is termed neutral because the filter will reduce the light going through the lens to the camera sensor in a uniform manner, whatever the colour conditions. Unless the filter has a manufacturing fault (and some do!), the colour is not impacted.

I read on a blog that ND filters should not be used when shooting objects which are not lit consistently in the frame. I think that advice is rubbish. As I explain below, the purpose of a Graduated ND filter is to even out different light exposures within the one frame (for example, a bright sky and a dark foreground), and there is absolutely nothing to prevent you from using a Grad ND with an ND, Black Glass or not. I do it often, and my point is demonstrated by most of the sample images in this Guide (below).

Neutral Density filters and Gradual Neutral Density filters are made with increasing levels of density, said to be equivalent to f stops. Thus, you do not need to use an extreme ND filter such as the Black Glass. For example, apart from several BGs of varying diameters, I also use a (slim) B+W 3-stop ND Filter (77mm) and, if I so desired, I could in fact stack 3 such filters to achieve the equivalent of a 9-stop BG. (I discuss stacking in more depth later on in this Guide.)

It is important to understand that when we talk about the BG, or other NDs of less density, we are usually referring, as in this Guide, to the round screw-in glass filter. This is why the respective diameter of your lens is necessary to know when making a buying, and usage, decision. Check the front end of your lens. The diameter, in millimetres (mm), should be printed there on the inside edge. Do not buy a screw-in filter without knowing this information.

Lee 10-stop ND Filter

Lee Filters entered the BG market in March 2010 with a 10cm x 10cm 10-stop glass ND filter called the Big Stopper, designed to slide into the same filter holder used for the Lee Graduated ND Filters (see images below). I could show you a picture of the BS, but all you have to do is imagine a black square and you’ve got the idea. To the feel it is a few ounces, as the glass is a few millimetres thick. On one side of the BS there is permanently attached 4 non-touching strips of low, thick, grey foam forming square pattern with the sides about a cm in from the edges of the glass.

The idea of the foam is twofold. Firstly, it allows the filter to snugly fit against the filter holder without moving. Secondly, and related to the first, it prevents any light seeping in between the filter and the filter holder. In this respect, it is akin to have a screw-on BG. The idea is that the filter slides into the first slot immediately in front of the lens. Note that the Big Stopper is supplied with its own semi-sturdy filter bag. It is not cheap – AUS $165. (I give supplier details in the Resources List.)

The Big Stopper is marketed as a 10-stop ND filter, but a card which comes with the filter states “Your BIG Stopper will have a density of somewhere between 9 1/3 and 10 2/3 stops.” Whatever. The purists may not be happy with a such a variable range of density, but to me its just a very dark Black Glass. I explain its use below under the heading How to use the Big Stopper.

Why would you buy one? Well, if you’re like me you have some lenses with a diameter of 82mm, and B+W stopped making its 10-stop 82mm ND filter in 2010, and Hoya only started making their ND x400 in 82mm in mid-2011. And since I’ve been unable to source a step-up ring from 77mm to 82mm, the Big Stopper was the only way I could do really long exposures with those lenses, for example, the Canon EF 16-35mm f2.8L II Zoom Lens and the Carl Zeiss Distagon 21mm f2.8 Lens.

I’m now onto my second Lee Big Stopper. The first one I left lying in its protective pouch in my Domke jacket, as you do, only to discover one day it had shattered into a million or so pieces. That’s the thing – the Lee Big Stopper is essentially a pane of glass, with similar thickness to, say, window glass. Very easy to break. Drop a screw-in filter from 15cm above the ground and it will bounce. Drop a Big Stopper from the same height and it may break in two …. or three ….

But … and this is a big but, take care of it (mine now has its own little tupperware slim lunch box for its home) and it will produce outstanding results. I mean really take care of it, because Lee cannot produce sufficient quantities of quality Big Stoppers to meet demand. When I picked up my current Big Stopper (May 2011) I was told that Lee was then rejecting 2 out of every 3 Big Stoppers made. Apparently it’s the glazing process they’re not happy about, and entire batches have been known to be rejected.

If there is one issue with the Lee Big Stopper it’s the colour casting. It’s not major, but it’s noticable. I discuss this further below when comparing the Big Stopper with the B+W 10-stop ND filter.

What is a Grad ND Filter?

Most Grad NDs are not round and not screw-in glass filters. Lee Grad ND filters, for example, are either square or rectangular. They are placed in front of the lens in special holders which have to be mounted on the lens by way of an adaptor ring. This is a circular metal ring which screws onto the lens (or onto the Black Glass which is already there) to hold the filter holder. Once again you need to make sure you buy an adaptor ring with the same filter diameter as the lens. And here’s a tip: if it’s a wide-angle lens get the wide-angle (slim) version of the adaptor ring because the normal version can easily appear in your photograph!

The filter holders allow you to slide a Grad ND filter up or down to achieve the light variation that you desire for the particular image you are shooting at the time. This is because the density of the filter ranges from zero (clear) to full (dense grey). They are ideal for lowering the brightness of a sky compared to the foreground, or brightening the shadows of the foreground, or creatively darkening or lightening specific areas of a composition.

This is because the Lee filter holder is also able to be completely rotated so that you can turn the filter to the left or right, depending on the position of the sun and hence the source of the bright light needing to be neutralised. The Cokin system is very similar, but here are 4 explanatory diagrams of the Lee filter system, which I have copied from the Lee publication linked to in the Resource List:

Note that the standard filter holder has slots for 2 filters, but that this is expandable. Mine has 3 slots. This means you can use, say, a 0.6 Soft Grad ND with a 0.9 Hard Grad ND or a multitude of combinations. It also means you can use one Grad ND upwards and another one inverted. Flexibility is the key.

If all that gear at the front of your camera looks daunting, don’t forget it is possible to use a Black Glass with a screw-in CP Filter. Or, believe it not, B+W do have several screw-in Grad NDs (see Resource List), but I can’t think of a reason why I’d use one, as you would not be able to adjust the graduation to suit the shot, as Tatiana did with this photograph, using the Hoya ND x400 with a Lee 0.9 Soft Grad ND which she tilted about 45 degrees to the right to lighten the shadow part of the composition, being the foreground rocks:

Note that Lee’s Grad ND filters come in densities of 0.3, 0.6, 0.9, and the more recent 1.2. You can also get either Hard or Soft versions of all densities. I started off with Soft ones but when I bought the 1.2 I went Hard. Why? Because I finally realised that the Soft has a really low density until you have slid the filter right to the end of the holder, way past the half-way point, which makes the “gradual” part of “gradual neutral density” a bit otiose. Then again it may just be because of the harsh sunlight in Australia and similar environments.

Now that Lee are selling a 10-stop ND square glass filter (the Big Stopper) that slides into a holder at the front of your lens exactly like a Grad ND, our options have significantly increased. Other manufacturers, like Cokin, will be forced to follow Lee’s decision, which was based purely on the worldwide demand for BGs. The BIG advantage to a slide-in filter is that you can use it with any lens, regardless of diameter.

Some photographers prefer not to use Grad NDs and instead bracket their shots and “fix” the light using Photmatix with HDR-like results. I prefer the natural method.

Some history

The shortage of availability of the Black Glass is due to the fact they were not originally designed for their currently popular uses, so Hoya and B+W are, albeit slowly, catching up with the burgeoning demand. I still get a smile from these words which, to this day, are used by Hoya on their website to describe the “special effects filter” we know as the Black Glass:

“Photographing solar eclipses and ultra-bright light sources can be extremely dangerous. This filter reduces light values by 9 stops to less than 1/500th of its original intensity and allows safe photography. It can also be used to achieve super slow shutter speeds in daylight to render moving subjects invisible.”

And this is what Schneider says about its B+W 10-stop ND Filter (excuse the translation):

“Its principal field of application is the observation and documentation of industrial processes with extreme brightness, such as steel furnaces, incinerators, glowing filaments in halogen and other bulbs.”

Yeh right, whatever.

(It’s worth noting that the 10-stop B+W Black Glass reduces light values to less than 1/1000th of its original intensity. Or in other words, the 10-stop BG only allows 0.1% of light to pass through it. Now that’s extreme.) I don’t shoot many solar eclipses or steel furnaces, none in fact, but I do use the BG across the entire range of light conditions.

What’s the big deal with the Black Glass?

A picture tells a thousand words, so I’ll let these samples do most of the talking:

Sample 1 – Colours

Turimetta Beach



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 27mm with Hoya ND x400 Filter and Lee 0.9 Soft Grad ND Filter, ISO 50, 30 seconds at f22, single RAW file.

On such a bright sunny day, a long exposure to achieve a misty sea look is simply impossible without a BG. Reason enough to use one. The above image was shot on a day so bright I had to stop down to f22 to achieve it, even with the ISO right down to 50. Extreme settings they may be, but the result is what I like to term hyper-real. The depth of colour is achieved partly from slightly underexposing, but also because of the drip feed, over the duration of the exposure, of the light hitting the sensor. (By that I mean there is a different light result from opening the aperture wide with a fast shot compared to stopping down and leaving the shutter open longer.)

However, My Canon 5D Mark II suffers from the Diffraction Effect which simply means that the more I stop down the harder it is for the 21 megapixels to receive an even share of light coming through to the sensor. The tech gurus say that maximum DOF is achieved at f8 or f9 on the 5D2, and stopping down further won’t achieve anything better and may in fact lose some detail. But most DSLRs do not suffer this problem as they do not have as many megapixels packed in. So, using a Black Glass enables you to stop down to f22 (and beyond, depending on the lens you are using) when shooting landscapes and seascapes and the like to maximise DOF (clear imaging of foreground and background subjects across the focal plane). Cool. For an example of extreme stopping down, in this case f32, check out this shot of Crispin Gardner’s using a borrowed BG (mine). Be aware though that stopping right down to the limit allowed by your lens, eg f22, for a long exposure with a DSLR can produce a banded haze effect with some filters, which I discuss at the end of How to use a Black Glass.

Sample 2 – Waterfalls

When our eyes are looking at a real waterfall we are seeing the water in a flow. Hence, to me, a photograph of a waterfall taken at speed, eg 1/100 second, is unreal because it freezes that flow. Such an image can be pin-sharp, which is fine, if not suitable, but when the water is just as pin-sharp as the surrounding rocks it looks, again to me, as being one-dimensional and hence it will not hold my interest regardless of how well composed it is.

Many photographers are on the same page, so with tripod handy and perhaps some filters like UV, Circular Polariser and Grad NDs, the aim is to slow the water down to capture more of the flow , as opposed to droplets frozen in mid-air. However, this presents another problem: the longer the exposure, the whiter the water, and hence the danger of overexposure or blown highlights. This is an example of what I mean. Again, it is one of mine, only this time taken over 1.5 seconds in an early and ultimately vain attempt at capturing movement:

Here’s another attempt of mine, this time faster at 1/50 second to try to get something of the movement of the water:

Now compare those with these shots taken with the Black Glass:

Britannia Falls



Canon EOS 5D Mark II, Canon EF 16-35mm f2.8L II Lens at 35mm with Hoya ND x400 Filter, ISO 50, 160 seconds at f8, single RAW file.

and this ….

Majestic



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 25mm with Hoya ND x400 Filter, ISO 50, 96 seconds at f14, single RAW file.

I know which type of water flow capture I prefer (you might be different). It still amazes me that a long exposure with the BG will retain the clarity of the water flow without blowing it out or turning it into a mushy snow-like blob.

Photography is about light. Allow for too much in the shot and no amount of post-production can fix it. If you don’t control it as it enters the camera, forget it. Neutral density filters help you to control light. This is the case even for relatively short exposures:

Tranquility Of My Eye



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 24mm with Hoya ND x400 Filter, ISO 50, 2.5 seconds at f8, single RAW file.

Here’s one more example of a low-light, shaded waterfall, only this time with minimal water flow and a really really l..o..n..g exposure:

Dante’s Glen Falls



Canon EOS 5D Mark II, Sigma 50mm f1.4 EX DG HSM Lens with Hoya ND x400 Filter and Lee 0.6 Soft Grad ND Filter, ISO: 50, f9, 300 seconds, single RAW file

One thing I should point out now is the absence of a need to tweak curves and levels. What you see with the above samples is what I shot. If you get the focus right and the exposure right (see below), the Black Glass will do the rest.

Sample 3 – Making things invisible

Where are the cars?



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 51mm with Hoya ND x400 Filter, ISO 50, 8 seconds at f14, single RAW file.

Just like Hoya says on its website, slow shutter speeds with the BG will render moving objects invisible. The above shot of Anzac Bridge in Sydney was taken during the middle of a workday, with scores of vehicles passing whilst the shutter was open. To be honest, I haven’t had time yet to explore this aspect of shooting with the BG, but you can well imagine the creative possibilities!

You can also use the BG to create a ghosting effect:



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 25mm with Hoya ND x400 Filter and Lee 0.9 Soft Grad ND Filter, ISO 50, 146 seconds at f11, single RAW file. Ten second delay.

Sample 4 – Clouds

The visual impact of taking a photograph showing movement contrasted with stillness can be extended from what the eye sees (waterfalls) to what the eye does not see, being in this sample, the movement of clouds over many seconds.

Indeed, it was monochrome seascapes with major cloudage happening that really got me going with the BG. But those were seascapes shot in the UK, where dark brooding skies appear to be the norm! Here in Australia, this is the best I’ve been able to manage:

Grey Dawn



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 24mm with Hoya ND x400 Filter and Lee 0.6 Soft Grad ND Filter, ISO 50, 98 seconds at f14, single RAW file

Sample 5 – Monochromes

Which brings me to my next sample of what the BG can do – really cool Monochromes. There is something special about the use of a 9- or 10-stop ND filter when shooting in Monochrome. For me, it doesn’t matter if the exposure is for

20 seconds …



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 24mm with Hoya ND x400 Filter, ISO 50, f10 at 20 seconds, single RAW file

or 30 seconds …



Canon EOS 5D Mark II, Canon TS-E 24mm f3.5L Tilt+Shift Lens, Hoya HMC ND x400 Filter, Lee 1.2 Soft Grad ND Filter, ISO 100, f9 at 30 seconds, single RAW file

or 45 seconds …



Canon EOS 5D Mark II, Canon TS-E 24mm f3.5L Tilt+Shift Lens, Hoya HMC ND x400 Filter, ISO 160, f6.3 at 45 seconds, single RAW file

or 60 seconds …



Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L Lens at 24mm with Hoya ND x400 Filter, ISO 50, f8 at 60 seconds, single RAW file

or 120 seconds …



Canon EOS 5D Mark II, Canon TS-E 24mm f3.5L Tilt+Shift Lens, Hoya HMC ND x400 Filter, ISO 160, f6.3 at 120 seconds, single RAW file

…or however many seconds, the Black Glass will always produce interesting Monochromes.

Sample 6 – Hand-held BG shooting

Believe it or not, with some cameras and in the right conditions, you can shoot hand-held with a Black Glass on your lens. Here is an example, shot at Mt Tomah Botanic Gardens in the Blue Mountains. Note that the ISO was 2000. No noise reduction was applied. (In other words, the sensational low-noise capabilities of the Canon 5D Mark II extend even further the photographic possibilities of the Black Glass.)



Hand-held Canon EOS 5D Mark II, Canon EF 24-70mm f2.8L at 24mm with Hoya ND x400 Filter, ISO 2000, f5 at 1/60 of a second, single RAW file

Sample 7 – In-camera zoom blur

I thought I had exhausted the creative potential of the Black Glass until Kym Howard superbly demonstrated how you can use the filter to create a long exposure with in-camera zoom blur, like so:

Mangrove at Sunrise



Canon EOS 500D, Canon EF-S 18-55mm f/3.5-5.6 IS Zoom Lens with Hoya ND x400 and half-grad ND2 Filters, ISO 100, f20 at 23 seconds

How did she do it? In Kym’s own words: I set my camera to Liveview so I could watch the timer count down easily. I thought after 17 seconds the image would be nicely captured on the sensor, and it was really just a quick zoom back and forward at the very last few seconds of the exposure. Brilliant! Do take the time to check out her portfolio.

Sample 8 – Infra-red camera

My very first attempt at IR photography using my converted Canon EOS 10D was with the ND x400:

Anzac Bridge



IR converted Canon EOS 10D, Sigma 10-20mm EX DC HSM Wide Angle Zoom Lens at 20mm with Hoya HMC ND x400 Filter, ISO 200, f22 at 60 seconds

The results can be variable though, and with an old DSLR like the 10D, stuck pixels will be a problem with long exposures. For the above image I applied Noise Reduction in processing the RAW image at the loss of detail. Here is a cut-away of the original before the NR was applied:

Other, longer exposures, eg more than 60 seconds, are problematic I’ve found, as it is hard to get effective shots without either completing blowing them out or getting black blobs. Hence, I’ve tended to use the ND x400 on shorter exposures with the IR camera.

OK, enough of the Show and Tell. Now we explore the How.

How to use a Black Glass

Gear

On the assumption you are not shooting fast into the sun, it almost (see Sample 6) goes without saying that if you are going to use a Black Glass you will probably need to mount your camera on a tripod. Also, I would recommend using mirror lock-up for enhanced stability and a remote shutter release for the same reason.

I recommend shooting in RAW when using the Black Glass. If instead you shoot in JPEG while using a Black Glass you will be decreasing the depth, clarity and colour that is possible from BG usage. Shoot in JPEG and you end up with 256 tonal values in an 8 bit format. Compare that with tonal values of between 4,098 and 65,536 when shooting in RAW and you have an argument going nowhere.

Wind

Got wind? Not good for using the BG. There are two reasons for this. Firstly, if you are shooting a long exposure outside in wind, trees will become blurred. While this may seem to be adding creative spice, to many an eye it doesn’t. For example, I need trees to be as still as possible in order to provide contrast to moving water. Secondly, and rather obviously, the longer the exposure the greater the risk you’ll end up with a blurred image because of wind. It only takes a slight vibration to ruin the shot.

But hey, the best time to use the BG is at dawn and sunset. It’s the best lighting conditions and normally at that time of day the wind is not an issue if its a clear day.

Taking the shot

When you screw in a BG onto the end of your lens, it is usually impossible to see anything through the viewfinder except black, unless you are pointing the lens directly at the sunlight on a clear bright day. Sample 6 was barely discernible in the viewfinder. Hence, before you screw on your BG you will need to compose your shot and focus your lens.

Getting your exposure right when using a Black Glass is just as important as when shooting without one. For example, leave the shutter open for too long and you’ll blow the highlights in your waterfall shot. The problem is that there is no point taking an exposure reading before you put the Black Glass on the lens, and your camera simply cannot give you an exposure reading after you’ve put it on. So, what do you do? Read on ….

There is mental arithmetic you can do to calculate exactly how many stops of overexpsoure you need to get an evenly-exposed shot after putting the Black Glass on, and I accept some photographers do this. Indeed, with film you really have no choice but to do the calculations unless you are comfortable with your settings through experience. Purists and pedantic pros may cringe when they read this, but personally I do not see the point in those calculations when using a digital camera, for several reasons, and thus I don’t stress about having to do them. I am not advocating lazy photography – you still need to know how to get an evenly-exposed result. But one reason I do not do the calculations is that I have never succeeded in getting anything near an evenly-exposed long exposure whenever I’ve done them, and I’m pretty good at mathematics. They always turned out still overexposed.

Another reason for not worrying about actually calculating the right exposure is that f stop compensation calculations assume you won’t also be using a Grad ND, which will darken your image. Try doing the calculations for that!

In the absence of doing those exposure calculations, it is simply a case of trial and error. Sixty seconds and your image is still dark? Well shoot again, this time at 90 seconds. A little too overexposed? Well try again, this time at 75 seconds. Each time you are narrowing down the exposure time. The more you use the Black Glass, the more comfortable you’ll get with calculating the right exposure and the less trial and error needed. Use your histogram as well to fine tune your settings and keep the range of your other variables to a minimum. Bear in mind that if you shoot at, say, 300 seconds, adjusting the next shot to 315 seconds is not going to make a discernable difference. A 15 second differential will, however, make a difference between 60 and 75 seconds. (Anyone not happy with me advocating the ‘trial and error’ method is welcome to go and invent a Black Glass Exposure Meter. I’d buy it.)

Yet another reason for not worrying about trying to calculate the right exposure to get a first time “keeper”, instead of just trial and error, is that you don’t have to also worry about compensating for the light entering the viewfinder during the long exposure. I discuss that particular issue further below, under the heading Total light control.

Don’t forget to turn OFF the Auto Focus (AF) on the lens before you press the shutter release with the BG on the lens, ie you need to switch the lens to Manual Focus (MF). If you forget to do this, when you press the shutter release the AF function will kick in and vainly try to find some light through the Black Glass, and usually that means the shutter won’t open. Been there, done that!

If you remember to switch to MF before taking the shot, don’t worry if you hear the camera’s AF-assist go “beep” when you press the shutter release. It just means that there was still enough light available to get a reading but it won’t override the MF setting or otherwsie re-focus the lens. This commonly happens when you are using the BG on a bright sunny day.

If you are using a BG on a zoom lens take care when screwing it onto your lens that you don’t push the zoom back at the same time, thus lowering the focal length and changing your composition, if not focus as well. Ninety-nine times out of a 100 you shouldn’t have a problem with screwing the BG on without pushing the zoom back in. This is because you will be doing it s..l..o..w..l..y to avoid dropping the filter! (Been there done that too!) And do try screwing it in while standing to the side of the camera rather than reaching over the camera from behind – it will be easier to get the thread matching up that way and you’re less likely to drop the damn thing. Trust me on that.

Live View focusing

If your DSLR allows Live View focusing (eg the Canon EOS 5D Mark II), you can, as noted by Mel Brackstone in a comment made in an earlier edition of this Guide, compose your shot with Live View with the BG on the lens. The manual steps I describe above are not then necessary. My only reservation in using this technique is the different way you are framing and composing as opposed to doing it through the viewfinder. I find the latter more precise, but that’s just me.

ND and UV filters

Originally, I wrote a tip to screw the BG on tight, otherwise you will get flare on the side of your frame. This is also recommended if you are also going to screw in a Cokin or Lee adaptor ring for your Grad NDs. I speak from personal experience of failing to screw in the BG tighter than the adaptor ring onto the BG – my 72mm BG is now permanently attached to my Lee 72mm wide angle adaptor ring. Not a good look.

But then I remembered something I encountered when first using the screw-in Black Glass. What if you already have a UV filter on your lens? And what if you have it there on a permanent basis? Try as I might, I cannot find any technical information which specifically addresses their use in tandem. In theory, however, you can.

Nevertheless, I no longer use any UV filters. Why? Three reasons:

UV filters are almost mandatory for film cameras. This is not the case for digital cameras, which are far more insensitive to ultra-violet light. Much of the material I have read pointedly argues that using a UV filter on a digital camera is pretty much useless and may in fact adversely affect image quality in certain conditions. The only UV filter that seems to be of real use for, say, a DSLR, is a UV-Haze filter.

When I first started using the BG, I would dutifully screw it onto the UV filter I dutifully had permanently on my lens. Then I would take the BG off and the UV would come off too, stuck to the BG. Grrrrr. On one occasion I permanently damaged a BG unscrewing it from a UV. One of them had to go (once I managed to separate them!). It was the UV.

I prefer to stack with the BG and Grad NDs. Leaving a UV on reduces the extent of effective stacking (discussed below) for no discernable benefit.

The only thing left for me to say on this issue is that if you want to keep using a UV filter on your lens, for protection or whatever other reason, I recommend taking it off before screwing in the Black Glass.

ND and CP filters

I’ve been asked if you can/should use a BG with an ND and/or Grad NDs. As for image quality, there is no reason not to. A CP filter will help in evening out the foreground/background (sky) exposure. Personally, I choose to use the Grad NDs for this purpose, but a CP will produce a different result, if not better, result, especially if shooting in colour.

The drawback is having to set your CP filter before screwing in the BG (or putting on the BS), then having to reset it after, back to the desired position. Thus you need to take note of the setting beforehand. Very bloody fiddly when there’s enough fiddliness already to cope with.

Stacking

Which brings us to stacking – using more than one screw-in filter at a time, in this case using ND filters of varying densities to achieve a BG effect or similar. Yes, it can be done and with great effect. Using several ND filters of varying densities also gives you great flexibility to mix and match according to the prevailing light conditions.

There are differing views as to the maximum number of filters that should be stacked. I’ve heard 4, I’ve heard 5. In theory it doesn’t matter though as much as the practical effect of so much stuff in front of the lens – barrel distortion – which manifests itself as looking like seriously-black vignetting. Not good. The more filters you stack, the more likely the front one will appear in your photograph.

For that reason, if you decide to use, say, three 3-stop ND filters stacked to equate to a 9-stop, I would recommend you use the slim versions of these filters. They will cost a bit more but will they will make a real difference, especially when using a wide angle lens.

Hot pixels, dead pixels, and stuck pixels

With really l…o…n…g exposures, you are bound to experience one or more of the above. This problem arises from variations in the individual responsiveness of the millions of pixels on your camera’s sensor. Type 1 are hot pixels, which will show up as white dots. Type 2 are dead pixels, which will show as black dots, and Type 3 are stuck pixels, which will either be red, blue or green. Often you will see all 3 types referred to as hot pixels.

I have found Type 3 to be most prevalent when using the BG, and it is not uncommon for all 3 colours to be evident. On the crappy Redbubble display page they are very hard if not impossible to discern, but if someone buys a large print of your Black Glass long exposure masterpiece and there are stuck pixels on it, it will be noticable so you need to be on the look-out for them on your computer monitor.

Here is an example of an image with a multitude of stuck pixels …



Infra-red converted Canon EOS 10D, Canon 24-70mm f2.8L Lens at 55mm with Hoya ND x400 Filter, ISO 100, 6 seconds at f11, single RAW file

…hard to see aren’t they? Here are some of them in a close crop:

Unfortunately, if your DSLR has a reputation for noise at around ISO 640 and above, your hot, dead, and stuck pixel problem will be multiplied if using the BG for exposures longer than about 30 seconds.

Some tips:

Stuck pixels and other types of problem pixels are easily fixed in post-processing, in exactly the same manner as spot removal. Do take the time to remove them. Enlarge your image to check for them if necessary.

You’ll get more of these problem pixels the longer the exposure and the higher the ISO. The pixel variations increase because the sensor heats up over a long exposure period. This is one reason I am really hesitant to shoot at longer than 7 minutes. I have seen images shot over 15 minutes and more and I do wonder how much “repair” work was necessary and if its good for the sensor. Manage the problem by keeping your ISO as low as possible. ISO 100 is ideal. Indeed, I would recommend letting your sensor cool down between really long exposures. (Shutter life ratings are not based on long exposures.)

Some cameras have Noise Reduction processing capabilities which will fix the problem before you download from your memory card. But there are 3 reasons why I never engage this function on my camera. First reason: in-camera Noise Reduction will cause a loss of definition, ie clarity, every time you use it. Second reason: if your exposure is, say, 120 seconds, the Noise Reduction process will take 120 seconds before you get to see the image in your viewfinder. I’m a patient man, but not that patient! Third reason: you have no way of controlling or adjusting Noise Reduction done in-camera. If I need to do some NR, then I prefer to do so myself in post-produciton. That way I decide on its strength and degree, not my camera.

Long exposures and small apertures

My good buddy Joe Meirose sent me a bmail recently about a problem he was experiencing when using the B+W 3.0 ND Filter. He kept getting a hazy horizontal artifact, as in this shot he kindly sent me:

One of the shooting specs he sent me leapt out at me – f22 and smaller. I suspected that was the problem, and when I researched it a bit I found someone else with the exact same problem with the exact same filter and who also used f22. My suggestion was to not stop down so far and be aware of the camera’s diffraction limit (discussed above). Joe tried this and it worked. I’m no expert but I suspect the hazy effect happens all the time when you greatly exceed the camera’s diffraction limit and that we just don’t see it as pronounced until we do a long exposure. Then again, I may just be pissin’ in the wind!

Total light control

This Tutorial has mainly discussed using the BG for long exposures but I should perhaps mention one aspect of lengthy shutter speeds which may need your input in certain circumstances – limiting the light entering the camera through the viewfinder if you are using a filter of much lower density [ie one which actually allows a light reading to be taken]. This is slightly off-topic, but I might as well mention it.

In normal shooting, your camera is taking a light reading, and opening and closing the shutter, whilst your head is rammed up against the viewfinder. In such circumstances, the light doesn’t enter the viewfinder. But, if you take a light reading whilst looking through the viewfinder [ie you are NOT using a Black Glass], then stand back during a long exposure, light will enter the camera and may affect your exposure.

If you are using a Black Glass, however, and apply the “trial and error” method of getting the exposure right, the problem does not exist because you are by definition compensating for any such light and all other light after each shot anyway.

But, if you are about to make a long exposure and you are shooting under Bulb and it is a very bright day and the sun is behind you and you are not using my recommended “trial and error” method discussed above, and you are using an ND filter of less than 9 or 10 stops, you may need to think about covering the viewfinder before engaging the shutter. There are several ways of doing this:

Stand behind the camera [I’m assuming you are taller than the camera on the tripod] Cover the camera with a dark cloth. This is the easiest to do! Tape some thick masking tape [electrician’s tape is the best] over the viewfinder. The thicker the better as you can then “hinge” it up or down. Use a small cap especially designed for this purpose [for example, Canon’s cap is on the camera strap; Nikon’s cap is a dedicated item]. Engage the viewfinder cover [some cameras have this feature].

Some also believe that engaging the mirror lock-up also obviates the problem, but I’m not sure about that. If you are shooting under cloudy conditions or in shade, the problem also does not present itself.

In any event, and as I said above, my method of trial and error in setting the exposure times by definition takes the viewfinder light issue into account – what you see in the LCD on the back of the camera is the result of any such light just as much as light entering the lens, so there’s no real “added” issue to worry about! In any event, if you are using a 9-stop or 10-stop ND filter, it is virtually impossible to take a light reading in any event! Nuff said.

How to use a Big Stopper

On first use of the Lee 10-stop “Big Stopper” ND Filter it becomes obvious you don’t have much room to play with. This filter is designed to be a full-on ND, not a partial Grad. You have to push the BS into the filter holder and line up the edges precisely to the right spot, being no gaps between the sides of the filter and the round edge of the filter holder. Get it wrong by a millimetre or two and your long exposure is stuffed by a huge flare. Don’t drop the bloody thing, and remember to place it in the filter slot nearest the lens.

It’s systemic, but a BS sometimes produces a slight colour caste (discussed further below). But its density is even throughout the frame, and indeed it is very very black. This was shot over 210 seconds at f5.6 (when I would normally stop down to f8 for a shot like this):

The Big Stopper versus the B+W 10-stop ND Filter – Colour casting

The following two images are JPEGs of 2 RAW files. One was shot with the Lee Big Stopper and the other was shot with the B+W 10-stop ND Filter. Both were shot in Landscape mode with the Canon EOS 5D Mark II and Canon EF 24-70mm f2.8L Zoom at 24mm, ISO 50, f2.8, over 15 seconds. All image settings in-camera were neutral and the only processing was to sharpen both images. Importantly, both images were also shot with Auto WB. The shot taken with the B+W 10-stop ND Filter was 5000K and -8 Tint in-camera, whereas the Lee Big Stopper was shot at 4900K and -4 Tint. When I tweaked the Lee Auto WB result to match the B+W’s result, the change was negligible for the purposes of display here, ie you wouldn’t see it. (Or I could have just lied and told you the colour temperatures were the same! Which they would hardly likely to be, by the way.)

Anyway, spot the difference?

Can you guess which is which? The Brown job is from the B+W, whereas the Blue job is from the Lee. Colour casting is inevitable whichever of the 2 you use. Using a Cokin or Tiffen or HiTech ND filter will also give you colour casting, but at much much lower densities. For example, Cokins give a pinky caste, whereas HiTech is much darker. The only exception to this that I have experienced is that the Hoya ND x400 Filter – The Black Glass – does not normally produce casting (actual copies are variable), but sometimes flaring. (If your Hoya flares, check your screw-in and if it’s screwed in tight you’ve got a bad copy.)

The colour casting is fixable, but only if you’ve shot in RAW. Of course, if your final image is in black & white, it don’t matter diddly. It is however rather niggly to have to tweak your White Balance in the conversion of a RAW file.

This is what Lee tell you in their System booklet (see link in Resources) and in the little pamphlet that comes with each Big Stopper:

Use of the Big Stopper may result in a slight colour cast. It’s worth conducting some tests to learn either which colour-correction filters to use in conjunction with the Big Stopper, or which white balance settings to apply. If shooting Raw, any colour cast can be corrected easily at the postproduction stage.

So, if you get in the queue to get a Lee Big Stopper, don’t go rushing back with it months later and ask for a refund because you don’t shoot in RAW. You’ve been warned. Of more general importance, however, is the fact that AWB and extreme NDs aren’t always a good combination, which I explain and demonstrate here.

The Hoya 82mm ND x400 Filter

To test the new 82mm Hoya ND x400 Filter I took my 5D2 and the Carl Zeiss Distagon 21mm f2.8 Lens up to the Blue Mountains and down into the valley below Bridal Veil Falls just after dawn. This lens hasn’t worked with the Lee Big Stopper as much as I would have liked. This is basically due to the colour casting and the very tight fit to ensure no light leakage (an 82mm wide lens is, well, wide!). I basically shot the same scene twice – once without the ND x400 at 1.3 seconds and once with the ND x400 filter at 25 seconds. Both shots were taken using AWB. Although this test was completely unscientific, for the sake of completeness, both images were converted straight to jpgs for uploading without any processing apart from sharpening. (Btw, all that white in the middle of the shot is foam, not blown highlights. Ruined the shot though.)

Without the 82mm ND x400 Filter



With the 82mm ND x400 Filter



Early days yet, but I’m pretty happy so far. And the thread on the filter just glided onto the metal Zeiss barrel. It felt right. There may be a slight brownness with the Filtered version, but that could also just be the exposure or the AWB getting freaky.

Anything else?

At this point I think I’ve exhausted my knowledge of the BG, if not you as well. I’ll leave this space here in case of something else coming to mind for later edits.

Those who inspire

For inspiration, check out the exquisite long exposure work of Donald Cameron (aka Mr Mono). Other RBers whose work inspires include Joel Tjintjelaar, and GlennC. Check out their portfolios – just amazing!

Resources

As I wrote above, prices for the BG vary significantly, depending on both the diameter required and the supplier. About the only constant is that the cheapest is the smallest diameter, getting more expensive as the diameter increases. This is one reason why the cost of going BG relates more to the actual lens you want to use it with and, unfortunately, most lenses for DSLRs are at the higher diameter level, being 72mm and 77mm. (Your lens should display its diameter on the inside of its front tip.)

As far as I am aware, only Hoya, B+W (Schneider), Light Craft Workshop (LCW) and Singh-Ray make BGs or similar. Several others make ND filters up to 3 stops, eg Tiffen.

B+W (Schneider)

The Schneider B+W Black Glass is available for lenses with diameters of

35.5mm 37mm 39mm 40.5mm 43mm 46mm 49mm 52mm 55mm 58mm 60mm 62mm 67mm 72mm 77mm

These are the densities available:

Graduated ND 0.3 – 2x (#501) Graduated ND 0.6 – 4x (#502) ND 0.3 – 2x (#101) ~ 1 stop ND 0.6 – 4x (#102) ~ 2 stops ND 0.9 – 8x (#103) ~ 3 stops ND 1.8 – 64x (#106) ~ 6 stops ND 3.0 – 1000x (#110) ~ 10 stops

Notice that B+W have some screw-in Grad NDs. As I discussed earlier in this Guide, the only drawback compared to, say, in-front-of-the-lens Grad NDs is that you cannot vary the graduation according to the shot.

Still, that’s the largest range on the planet. The Schneider B+W website has a search facility for that special filter you want. As of March 2011, it appears to be up-to-date. Here is the most recent B+W price list, as of March 2012, dated 1 April 2011. Frustratingly, B+W lists everything in order of filter diameter. The price list also does not tell us what currency they are referring to, but I assume it’s US dollars. Don’t freak out at the prices, they are way above what you can actually find as being your cost. Here is a useful page on the B+W website with links to other filter information.

Here is the B&H page for B+W BG filters. As you can see, B&H have an extensive range of ND filters and they categorise availability. Their service has been excellent, but be aware that availability of the Black Glass can change quite quickly depending on the diameter, so I would recommend emailing them your desires before placing an order. I have always received a prompt response, and sometimes the on-line catalogue lags stock being on hand.

For Australians, I bought my first B+W filter from here but be aware they may be currently out of stock. It may be better to buy through B&H (see above link) given the greater range in stock and the improving Australian dollar against the greenback.

However, Jole Aston commented below (7 January) that The Camera Exchange (Lonsdale St, Melbourne CBD) has stock of the ND filters in 77mm thread, $145 for a 10 stop B+W. That’s incredibly cheap! Their website states: “There are no products to list from this manufacturer” so I sent them an email asking for confirmation. The reply came back that they had 2 in stock. They now have only one as at 10.30am AEDST 8 January (sorry!).

Dan Biggins commented below (6 January) that the B+W is scarce in the UK at the moment. He ordered his #110 on 6 October 2009 and it arrived 2 months later.

There’s also Adorama, but I’ve never bought off them so I can’t really comment. Here’s their B+W BG catalogue. Their prices appear similar to B&H’s.

Also, check out this guide to spotting fake B+Ws, especially those on offer on eBay.

Hoya

Hoya Black Glasses are available in

49mm 52mm 55mm 58mm 62mm 67mm 72mm 77mm 82mm (from mid-2011)

Here is the main Hoya ND x400 web page. Note that Hoya NDs can be had in the following grades of density:

x2 – reduces light by 1 stop. x4 – reduces light by 2 stops. x8 – reduces light by 3 stops. x400 – reduces light by 9 stops. Half x4 – Half NDx4, half clear – but 58mm is the largest diameter

Here is the B&H (USA) on-line shopping list for Hoya ND x400s. Here is the equivalent Adorama page.

For Australians, here is where I buy my Hoyas. They have a physical shop in North Sydney and their Hoya prices were the cheapest I’ve seen until recently. A comparison of prices can be had here, here, and here.

Light Craft Workshop

LCW has only an on-line presence here. In January 2010, LCW published claims that Hoya is misleading the market by its 9-stop ND Filter and launched its own BG, which is currently available only in 77mm for US$73. As of November 2011, LCW was still defaming Hoya on its website. Here are the claims, with spelling and grammar left as is:

“This is the L.C.W. ND500 neutural density filter, providind a real 9 stops density. ND400 is one of the most common ND filter photographers use and manufacturer always misleading people by saying that could provide a 9 stops density, which is actually 8 2/3 stops. Now, Light Craft Workshop would like to introduce you the real 9 stops ND filter, ND500 MC. L.C.W. ND500 MC allows to reduce shutter speed from 1/500 sec to 1 sec, which is a real 9 stops reduction of light. Designed with thin filter ring, this helps to avoid vignetting on ultra wide angle lens and multi coated glass helps to provide a better image resolution and anti-flare performance.”

Regardless of what I may think of the above claims, which is not much, the fact is that the Hoya ND x400 is “one of the most common ND Filters” for a reason, and that is it is an excellent filter. Period. Indeed, its colour management excels, whereas when I look at look at the only colour image on RB I know of to date taken with the LCW ND500, it appears LCW has major colour casting issues regardless of whether or not it is the only, true, 9-stop ND filter.

Singh-Ray

I wanted an 82mm Black glass to use on my Carl Zeiss Distagon 21mm f2.8 Lens but until June 2011 nobody made them at that diameter. Instead, I acquired an 82mm Singh-Ray Vari-ND Filter. These things are significantly more expensive than either Hoya or B+W and, in my opinion, only worth a fraction of a Hoya or B+W, if anything at all. They are constructed in exactly the same way as a Circular Polariser, only much chunkier. They proclaim to give a range of 2 to 8 stops. I don’t think they do. Anything above about 6 produces severe vertical banding. Worse, the higher the stop the greater the colour casting throughout the frame. And to cap it off, I cannot use it, ie vary the ND factor, with the lens hood on. A complete waste of money and my biggest gear mistake to date.

Lee Filter Systems

I use Lee polysester filters for black & white photography, Lee resin Grad NDs for all photography, and many Lee resin special effects filters. Given that level of investment, I don’t use Cokin. (I’m more than happy to add Cokin links if anyone wants to supply them to me.)

Lee Filters have recently redeveloped their website. Regardless of whether you intend to spend money with them, have a look at this page on their site. It demonstrates brilliantly the many uses of their filters and there are also now training videos and awesome “Without Filter” and “With Filter” comparisons.

If you only want to go basic with Lee, I suggest simply buying either one resin 0.9 Hard Grad ND Filter or 1.2 Soft Grad ND Filter (about $120) and/or the set of 4 polyester filters for black & white photography ($20 each).

For Australians, Lee gear – including the all-new Big Stopper – can be acquired from either Mediavision or Vanbar. I have nothing to say about Vanbar as I haven’t shopped with them, but I am at a regular at Mediavision. Geoff is the man. If you’re in or near Sydney they are located at 4 Monash Road Gladesville (just off Victoria Rd at the lights). You can check out their Lee page here and/or email them – sales@mediavision.com.au. (Ph: 02 98164055)

You want more?

If a BG is too expensive, consider paying a few dollars for a welding filter. That’s right, the dark glass that welders place at the front of their helmets to protect their eyes. Thanks to monocotylidono for the heads up. Check out his Journal, with samples!

Well, that’s it for me. If you got this far with this Tutorial, you may one or more of my other tutorials of interest as well.

Cheers

Peter

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