How To Use Neutral Density Filter

WHAT IS A NEUTRAL DENSITY FILTER?

A neutral density filter (ND filter) is simply a filter that'southward cuts the amount of light that enters your camera'south lens. They are most normally used in mural photography when a photographer wants to create a longer exposures than what would normally be possible using but the camera'due south internal settings. In this article you will learn how to use a neutral density filter and how to summate long exposures.

Imagine that you desire to crate a 30 second exposure in brilliant sunlight. Even with the camera set to ISO 100 with an aperture of f/22 the shutter speed will still be relatively fast. The only fashion to go a longer exposure in this state of affairs is to place a neutral density filter in forepart of the lens.

TYPES OF NEUTRAL DENSITY FILTERS.

In that location are three types of ND filters. Solid ND, graduated ND, and variable ND. Graduated filters are useful when you but want to darken a portion of the image such as when the heaven is brighter than the foreground. While these filters can be quite useful, a whole article could be written about their application then I volition save that for a future postal service.

Solid and variable ND filters darken the entire image which allows the photographer to blur anything that is moving. I highly recommend purchasing solid ND filters over variable ND filters since variable filter are frequently more trouble than what their worth. A variable filter allows yous to change the density of the filter but past turning it. Audio as well skilful to be truthful? That'due south considering it is. You will spend a little more money purchasing multiple solid ND filters but the quality of a solid neutral density filter will be much higher than a variable filter. Variable ND filters will ofttimes cause artifacts on wide angle lenses and have thick frames which tin cause pretty terrible vignetting even without stacking filters.

SQUARE VS. Circular ND FILTERS

When choosing a solid ND filter you can either choose a screw on filter or invest in a filter holder system. If you're new to neutral density filters, you may want to outset off with a spiral on filter or two. In fact, I love my round ND filters by Breakthrough Photography due to their natural color, ease of setup and low profile. A filter organisation can have a flake longer to setup and when the lighting is skilful I want to get the shot, not wrestle with my gear. Foursquare filters also have more expanse which means more area for wet to collect when shooting near the body of water, waterfalls, or in the pelting. With that existence said, good filter systems do take their advantages. They allow photographers to stack solid and graduated ND filters with little to no vignetting. Again, I adopt Breakthrough Photography.

WHEN TO USE A NEUTRAL DENSITY FILTER.

Landscape photographers utilize ND filters when they desire to create silky smooth water. This effect works wonderfully on waterfalls, creeks, lakes and oceans. Long exposures can likewise be used to create dreamy streaks in a cloudy sky and can even be used to remove moving objects from a scene. If your shutter is long enough and the objects are moving fast plenty, they volition not even testify upward in the shot!

Portrait photographers will sometimes utilise low density ND filters when working with flashes. Since portrait photographers mostly like to use a very shallow depth of field (open aperture), it may non be desirable to stop down the exposure using the aperture and if the ISO is already maxed out the next best choice is to use a i or two end neutral density filter.

HOW MANY STOPS SHOULD A NEUTRAL DENSITY FILTER BE?

ND filters come up in a wide variety of densities that are described in stops. A light ND filter may simply be one or two stops which is perfect for portrait photographers using a flash while a very dense ND might be 15 or twenty stops. And then how many stops should a ND filter exist? That depends on the amount of light that you're working with and the desired results that you're going afterward.

For most practical landscape uses, three, vi and 10 stop filters are the about common. Three stop filters are nifty for when yous need to button the exposure just a little longer. I find iii stop filters to exist actually useful on the far edges of day when the calorie-free is already quite low simply the at that place's withal too much calorie-free to create the length of exposure I'm looking for.

Six stop filters are perhaps the most flexible of the solid ND filters since they are dark but not welding glass dark. Most modern cameras will all the same be able to focus through a six finish ND filter in decent lighting conditions without a problem. If I were to selection merely one neutral density filter to carry with me, it would exist a six terminate filter.

10 stop ND filters are very dark and are capable of achieving thirty second to two minute exposures in the middle of the day. These filters are useful for completely blurring moving h2o so information technology looks like a soft haze. 10 and fifteen finish filters are also very good for removing moving objects from an epitome every bit if they were never there in the beginning place.

CALCULATING LONG EXPOSURES

When working with dense filters such as 10 stop NDs it may exist necessary to calculate the exposure manually considering the light meter may non exist able to requite a proper reading through the dark drinking glass. Luckily, calculating long exposures is not every bit hard as information technology may seem. Any time the shutter speed is doubled or halved y'all adjust the exposure of the prototype by one stop. Similarly, the exposure is adapted past i end whatsoever time you lot double or halve the ISO.

For example, if I take a photo at ISO 200, for i second I can get the exact aforementioned exposure by lowering the ISO to 100 and increasing the exposure time to two seconds while leaving the aperture where is was. In this case I took away one stop in the ISO merely I as well added a cease by doubling the exposure time then the shot is effectively the same exposure.

Calculating aperture requires a lot more than math than anyone in their correct mind is ever going to do in the field. Luckily, it is still very easy to calculate the aperture's effect on exposure because we know that all modernistic cameras operate in 1/3 and 1/two cease increments. Most cameras will adjust exposure in 1/3 increments by default but many tin be programed to shoot in 1/two stop increments every bit well.

Bank check your camera's menu to meet if you're shooting in 1/3 or 1/2 end increments. Hint: If yous take never changed the increment settings in your photographic camera, yous're probably shooting in i/3 stop increments. If your camera is ready to 1/iii terminate increments, adjusting the aperture dial by three clicks will adjust the exposure by one full finish. If you camera is set to i/2 stop increments every two clicks volition suit the exposure by one terminate.

Existent WORLD 10 End ND Case

At present permit'due south look at a real earth situation using a ten cease ND filter. As mentioned above, your lite meter might not be able to summate the proper exposure due to the large amount of light that is being cut by the filter. For this reason is is best to set your photographic camera's mode to manual. If there is a lot of light you might be able to meter through the filter but if you're shooting on the edge of twenty-four hour period you may take to calculate the exposure manually.

So allow's walk through how to shoot with a 10 stop ND filter in low light. Commencement we'll take a shot without the ND filter. For this instance let's presume that our settings without a filter are ISO 100, f/16, i second.

After calculation the 10 stop filter we have to find a way to add ten stops of light to our exposure. We tin can do this past adjusting the aperture, shutter speed, ISO or a combination of the three which is ofttimes the route that I end upwards taking. If we're adding a ten stop filter, we're probably going after a very long exposure then we'll beginning off by adjusting our shutter speed.

Passing Day Over the Bay — five ane/2 minute long exposure

Recollect that nosotros were shooting at ane second before we added the filter. To add one stop of calorie-free we'll adjust the exposure from one second to two seconds. Now we merely have nine more stops to go! Nosotros can double the time again to four seconds and then double that to eight seconds which leaves u.s. with seven more stops to go. Our exposure is still relatively brusque so let'due south double it again to sixteen and and then to 30 seconds. We're half mode in that location! (I know I shaved off two seconds only I'm going to assume that about people reading this are like me and not math wizards. Information technology's best to keep things as simple as possible when in the field.)

At this signal nosotros demand to switch our photographic camera to bulb mode in oder to achieve an exposure over thirty seconds. Brand certain to pay attention to the discontinuity settings when switching from transmission to bulb mode. The aperture is often gear up independently between manual and seedling modes. After making certain our aperture value remained at f16 we can program in our exposure using an intervalometer timer.

Notation: If y'all do non take an intervalometer, you tin use a regular cable release and picket the stopwatch on your phone. Furthermore, many new cameras have builtin intervalometers.

Let'south keep to double our exposure to i minute, and so to two minutes and finally to four minutes. Nosotros have gained viii stops of exposure but we withal take two more to go. We could continue to double our exposure only we'd end up at 16 minutes!!! Rather than shoot for 16 minutes, permit's add together a stop by increasing the ISO form 100 to 200. Finally, let's add our final stop by opening up the discontinuity from f/16 to f/11.

APPS FOR CALCULATING EXPOSURES

If the above case has your head spinning, don't worry. In that location'due south are many different apps that can be used to assistance you calculate the proper exposure. LE Calculator is a free app that volition calculate long exposures and even comes with a built in timer in case you practice not have an intervalometer. PhotoPills is a paid app that has a long exposure calculator amongst many other photography planning tools. It's a fantastic app and I highly recommend it for whatsoever landscape photographer.

DEALING WITH LONG EXPOSURE NOISE

Long exposure times equate to added noise fifty-fifty at low ISO settings. As long every bit your exposure does not exceeded five minutes, you lot should take relatively depression amounts of noise. Noise is created when the sensor heats up during a long exposure. If information technology's cold outside, yous may exist able to go away with longer exposures earlier noticing much racket. Full frame cameras will handle ultra long exposures amend than crop sensor cameras. While shooting for longer than five minutes can add together dissonance to a shot, sometimes the results tin be worth the added noise. Experiment with different exposure times and run across how they event the image. If needed, you tin employ some noise reduction during mail service.

DEALING WITH Changing LIGHT

When shooting on the edge of mean solar day it's important to remember that the globe moves faster than you think. The amount of light falling on a scene tin change dramatically in the matter of a few seconds, let alone a few minutes. Changing light throws ane more variable in our exposure equation that can exist very hard to predict. When shooting during sunrise, y'all will need to subtract a stop or two to compensate for the increase in calorie-free that will happen as the sun continues to add light to the scene throughout the exposure. The opposite of this is true at sunset. During sunset you will have to add a stop or two in gild to compensate for the fading light.

ISO and aperture can sometimes be more effective at controlling exposure when the calorie-free is speedily changing because they do not add or subtract whatsoever time to the exposure. Imagine that the sun is setting and your exposure is already 5 minutes. If yous add a terminate of light using the shutter, your shot will then be ten minutes long. The amount of light that disappears in those added 5 minutes will more than similar be greater than the terminate that y'all added. Therefore, a better choice might exist to boost the ISO or open the aperture.

Even during the heart of the twenty-four hour period, moving clouds can cause each long exposure shot to wait quite different. It'southward a practiced idea to try multiple shots if at that place are a lot of clouds in the heaven. The difference a few minutes makes can be amazing.

I will often accept a few shots without a filter if the light is looking good. This way I tin can blend the shots if the light changes or at the very least I have a few solid exposures that were taken with a fast shutter.

WATCH OUT FOR UNWANTED Motility.

Pay close attention to elements within the scene that could cause unwanted motility blur. Tree branches and plants rarely stay nevertheless for very long. Sometimes the blurry edges of plants can exist an interesting look. Other times you may desire the vegetation to stay even so. If your exposure is but a few seconds long you may be able to time your exposure so it happens when the air current is not blowing. If y'all are attempting a very long exposure there might not be much you can practice other than embrace the soft edges from the current of air. Photographers who have strong Photoshop skills might exist able to blended an image using one fast shot that was taken without the ND filter and i that was taken with the ND filter. This technique can prove to be quite tedious though then I volition not comprehend it in this article.

DON'T LET LIGHT LEAKS RUIN YOUR SHOTS

Calorie-free is a photographer's all-time friend but it tin can also be our worst enemy. Light leaks will surely ruin a skilful long exposure. The telltale sign of a low-cal leak is a magenta cast that appears in only a portion of the image. It is always a expert idea for DSLR shooters to comprehend the photographic camera's eye piece especially if the sun is backside the photographic camera. If yous fail to embrace the eyepiece, calorie-free tin can enter the camera from the rear and cause a terrible color cast.

High endNikon DSLR'south have a a convenient eyepiece curtain that should exist used whenever performing long exposures. If your camera does non accept a built in eyepiece comprehend you may want to acquit some gaffers tape that tin be used to temporarily cake light while y'all are performing a long exposure. Mirrorless shooters do not accept to worry well-nigh rear low-cal leaks since there are the view finder is electronic.

Light leaks can as well occur when using filter folders. Sometime calorie-free volition pitter-patter into the filter and bounce around during the shot. For this reason, I prefer screw on filters in about cases. If you lot notice a light leak when using a filter arrangement, try to use gaffers record to stop the leak.

NEUTRAL DENSITY FILTERS AND Colour CAST Issues

Most ND filters have at a piffling bit of a color cast. Some are worse than others. Breakthrough Filters tend to be the virtually color neutral filters that I have found and they are backed by a twenty year warranty.

DARK POLARIZER FILTERS

In recent years, filter companies take started to make night PL filters. A night PL is a combination of a neutral density filter and polarizer all in one. While virtually all in ane products are terrible, dark PL filters work amazingly well! They come in diverse densities and remove of the demand to stack a ND and PL filter together which reduces the chance of vignetting at wider focal lengths.

Conclusion

Neutral Density filters are a great way to add together atmosphere to a shot with moving elements. I recommend experimenting with various density filters and exposure times to gain a greater understand of how ND filters work. Notice the differences in a half second exposure and a two second exposure. And so compare those results with a xxx 2d exposure and a five infinitesimal exposure. Practice gauging exposures under changing lighting conditions and run across if you can accurately predict the right exposure. Watch your histogram and endeavor to bring it to the right side of the graph.

Happy shooting!