What's the best application of a neutral density filter or a graduated neutral density filter? Has anyone used them and if so how were the results? Other than reducing glare, does a polarizing filter essentially accomplish the same thing?
I used it for sunrise a long time ago. Back during the clone wars, err. sorry. When positive film reigned supreme, and IS hadn't fully migrated to the professional line. I would use it for long exposures, such as night, when you need the extra exposure time to eliminate distractions (traffic, pedestrian or otherwise). I would use a grad ND for shots where you have a large variance in proper exposures between two sides of your picture, such as the sky and mountains, so you can properly expose both. I think HDR is reducing the need for that. ND filters are for when you don't want to eliminate glare in that fashion, just reduce the amount of light.
a polarizing filter reduces glare off shiny, non-metallic surfaces such as water, glass, etc. it also makes the sky a darker blue while making the clouds "pop" right out of the photo. it only works when you are 90 degrees to the light source, however. think polarized sunglasses and their effect and you'll get the idea. a regular ND filter is like sunglasses for your camera. nothing more or less. a grad ND filter is used for landscapes and such because it goes from clear to dark in subtle shades with a gradient.
This is where you take multiple exposures of the same scene, basically exposing for everything in the scene, from the highlights to the shadows. Then the exposures are combined and create a 'high dynamic range' photograph, which really wasn't easy to do until digital photography came along. I know Ansel Adams did this in the darkroom to some extent - the same thing with RAW processing and HDR in a way.
Depending on the ND's opacity, they can be used to avoid blowing out highlights when the camera's aperture cannot restrict far enough, or when you don't want to use a minimum aperture to avoid diffraction and maintain detail. They are also very handy for IR photography - if you get an IR cut filter, often it can be useful to stack an ND8 or even two (ND4, ND8) filters to get deeper blacks in skies and water. And NDs are invaluable when you want to do slow-shutter work in daylight...such as photographing waterfalls with ribboned water effects, and blurring people into ghost streaks as they walk around. Most cameras won't be able to close down the aperture enough to allow several-second shutter speeds in daylight. Figure for around 2 stops of light restriction with an ND4 (.6), and three stops for an ND8 (.9) filter. Then there are the serious ND filters, such as my ND400, which has approximately a 10-stop restriction. This allows you to fire off 30-second shutters in the middle of the sunny afternoon. These are all solid ND filters. As mentioned above, the graduateds are useful for darkening parts of the photo more than others. Polarizers do usually offer some light restriction - usually around 1-stop loss. But primarily, you can reduce glare and reflection off of reflective surfaces. It's particularly fun to stand in front of a plate-glass window which is reflecting the scene behind you, look through your polarizing filter so you can see all the reflections, then slowly turn it 90 degrees and watch the reflections disappear and the interior behind the glass suddenly coming into view.
Wow. http://www.adorama.com/HY77ND400.html?s ... &item_no=5 $127 for a 77mm. And I was just thinking about this after reading your post - these sizes weren't as necessary for night exposures with film due to reciprocity failure - you had to extend your exposure time anyway, plus negative film is forgiving. Digital sensors aren't. You can blowout your highlights too easily, even at ISO100 and f/22 (which is bad in and of itself). Any light source will be blown out if you are trying to eliminate pedestrians (a walkway for example). Waterfalls really need 6-10, not 1 or 2 seconds...but you can't get that with digital and not blow out highlights. Your ND400 is very appealing.
you can always stack a few nd4's together to get the same effect, but you are adding more glass to the equation which isn't as good (more things to go wrong - less is more in this case). you might also get to where you start to vignette at wide angle with stacking...
Keeping in mind that this was when I first got the filter, and with my skill levels being a few notches lower (and the castle in the background gives away that this shot isn't recent!)...here were some of my first experiments with the ND400 in the early afternoon: 10 seconds: 5 seconds: And a few at home the first few weeks I had the filter... 5 seconds: I've been using it alot for IR work - and was actually planning on using it for some more daytime long-exposure shooting over the next month or two. It's a unique filter! Tim - you're right about the stacking - you'd have to use 3 ND8 (.9) filters to get as much stoppage as the ND400 - even with good quality filters, that's alot of extra glass to be shooting through! The ND400 is pricey, but can be an interesting addition to your bag.
Interesting information guys. I was just thinking about ND filters a while back.. personally I'd concluded that there was no use for them in the digital age. But this is an aspect that I didn't think of. In truth I'm completely opposed to the practice of doing blurred exposures of waterfalls. It's just my taste, I've never liked the blurred waterfall shots. That's no critique, Justin, it's a standard photographic technique that you'll find in practically any book on photography, it's just that I've never liked it. I do short exposures in situations like that to get crisp water. But the crowd exposures are interesting. I love how some people leave indistinct blurs, some are more or less standing still, and some leave multiple ghosts. A still image that gives you some concept of the passage of time. I'd pick up one of those ND400s.. but not at that price. If I was going to spend that much on a filter I'd get a good polarizer. I really should, but.. I'm not entirely eager to lose two stops of light in the process, I'd be constantly removing it and then having to attach it again when I'm doing zoo shooting (although the reflection reduction would definitely be useful).
Dan, the price depends on the size. I was just looking at 77mm, since that seems to be Canon's previous generation max size* unless you had to use a drop in/gelatin filter. (Next generation begins with the 16-35 f/2.8L II USM, 82mm filter size)
Another interesting option that some of you may already know, but others don't - get two circular polarizers. If you can find those cheap - having two circs on at once basically gives you infinite stops - by adjusting the two polarizers opposite eachother, you'll cross their polarization which results in full visible light block. As you adjust them off, they gradually ease into more visibility, so the effect is like having an infinately variable ND filter ranging from roughly 1-2 stops to 10+ stops to only IR. Whether the 4 pieces of glass added when shooting through 2 circ polarizers are more detrimental to detail, I don't know. BTW - my ND400, which was at a smaller 58mm, was $42.
