Elsewhere, we have covered how to deal with extreme dynamic range problems in outdoor photography. We have looked at solutions involving post-processing and even spent some time on HDR techniques. But what if there was a way to deal with the problem of dynamic range in-camera?
Turns out, there is. It is called the graduated neutral density filter (or a “Grad ND” for short). It darkens the top of your picture (the sky) without affecting the bottom portion (the foreground). It is a rectangle piece of glass that fits over your lens where:
- the top portion of the filter has a dark coating over it so that it lets in less light, and
- the bottom portion of the filter is clear glass.
Because a graduated neutral density filter is a rectangle piece of glass that fits over your lens (and not a screw-on filter), you will need a holder to attach it to your camera. It is a completely different style of filter from what you may be used to if you bought a polarizing or UV filter (which are circular).
If you don’t have one, this article is going to show you what you need to know to choose the right one.
Choices in Buying a Graduated Neutral Density Filter
Why would you need to read a whole article about buying one filter? Because buying a graduated neutral density filter is confusing. There are lots of facets to this decision.
Like everything else, there are a number of brands to choose from. The main three we will talk about are Cokin, Formatt Hitech, and Lee. In addition, there are different size filter systems. The bigger systems cost a lot more, but if you buy one too small the holder may show up in your picture. After you choose your brand and size, you then have to get the right sized adapter to connect the holder and filter to your particular lens.
Even once you choose a system, there are a number of decisions to make regarding the filter itself. How strong of an effect do you want? These filters come in various strengths. What kind of transition between clear and dark do you want? You can get one with a gradual or abrupt transition.
As with all things, my goal is to make this as simple for you as possible. Therefore, let’s start off with a chart showing the options you should consider. Take a look at this chart, and then we will get into some of the particulars.
Note that there are smaller kits, but they are not listed them here because they are likely unsuitable for you (they are really for compact cameras); and there are also larger kits, but they are very expensive and you will not need them (especially if this is your first Grad ND). If, however, you want to see a complete chart with all the options, click on the chart above and a pdf with that information will open.
Recommendation and Answers
Rather than go through every characteristic of Grad ND filters, let’s just jump to my recommendation and explanation in a Q&A format.
Which System Should I Get?
If this is your first Grad ND filter, start with the Cokin P-Series. It costs a fraction of any other system. It is probably the most commonly used system and the filters are very good. If you later decide you hate it for some reason (and I don’t think you will), you are only out about $55. It might be all you ever want/need though. It is what I have used for several years.
Further, even if you decide you don’t like Cokin filters, you can get 85 mm Formatt Hitech filters and keep using the same Cokin holder and adapter.
Won’t Using the Smaller Model (Cokin P-Series or Formatt Hitech 85 mm) Cause Vignetting or the Filter to Show in My Pictures When I Shoot at Wide Angles?
First of all, yes, as the chart above shows, shooting with a focal length any wider than 35 mm will cause vignetting in your pictures. If you go much wider than that, the holder itself will show up in your picture. As an example, take a look at the picture on the left, which was shot at 24 mm:
When you shoot at 24 mm (or wider), not only is there vignetting, but the holder is actually in the picture and shows up as black edges. In this case, as is shown in the picture to the right, I just cropped it out and everything was fine.
Besides cropping out the black edges from the holder, there are things you can do to fix this problem, such as:
- Buy a special wide angle holder for the Cokin P Series. It costs $25, so it will increase the price of the system a little bit (the normal holder is only $12), but it is still by far the cheapest system. It holds the filter closer to the lens, so the brackets won’t show up as much. Using this holder will allow you to shoot all the way out to 20 mm without vignetting.
- If you don’t want to buy the special holder, you can actually just hold the filter in front of your lens when shooting without using a holder at all. I’ve one this countless times and it works quite well.
- If you are worried about potentially shaking your camera when you hold the filter in front of the lens, you can also use rubber bands to affix the filter to the lens.
Since writing this article, I have taken possession of the wide-angle holder for the Cokin P-Series. It works great. I would very much recommend getting the wide-angle holding instead of the normal holder. Doing so will allow you to shoot with extremely wide focal lengths – even wider than the larger (and more expensive) filter systems allow.
What About Using A Grad ND Filter Without a Holder at All?
There is nothing wrong with this, and I actually think it is a good idea. As mentioned above, you can just hold the filter up to the lens, and thereby eliminate any vignetting in the picture even when using the smaller (85 mm) filters. If you are worried about shaking your camera during the exposure, you can affix it with rubber bands (but frankly I wouldn’t bother).
In addition, you will find that you will use your Grad ND filter more often this way. Getting out the holder and attaching it to your lens is a hassle. Sometimes you might forego using the filter at all to avoid the bother of getting everything out of your bag. But just holding the filter up to the lens is easily done.
Why Do I Need an Adapter?
The adapter allows the filter holder to screw into the face of your lens. Lenses have different diameters, which are measured in millimeters, so you will have to get the right one for your lens(es).
Be careful – the diameter of the lens is not the same thing as the focal length. They are both measured in millimeters, which can lead to some confusion, but they are different. Many times, the diameter is printed on the front of the lens, as in the picture to the right.
Which Filter Should I Get?
Start with a 3-stop, soft transition filter.
These filters come in a variety of strengths, which is measured by the amount of darkening applied to the top of the picture. The strength of the filter is measured in stops. The most common strength – and the most useful – is 3 stops. Any less than that and it will not be strong enough to even out the exposure (i.e., the sky will still be too bright). More than 3 stops is less common and usually not necessary.
Next, you have to choose how the filter transitions between clear and dark. Some filters have a soft, gradual transition, while other times it is a hard edge. Sometimes the transition is only in the middle of the filter, while other times the transition covers the entire length of the filter. The most useful are those that limit the transition to the center, with a soft transition.
If you get the Cokin P-Series, get the Cokin 121S filter. That filter might be all you ever need (it is the only one I carry with me, despite owning several others), but you can always add more filters to your kit if you find you have different needs.
Can I Mix Brands? In Other Words, Can you Use a Cokin Holder and Adapter and a Lee or Hitech Filter?
Yes. Cokin P Series and Formatt Hitech 85 mm filters are interchangeable. At the 100 mm size, Cokin, Hitech, and Lee are all interchangeable.
Conclusion and Next Steps
If you do not have a Grad ND, try out the Cokin P-Series 121S. The holder, adapter, and filter will only set you back about $55 (or closer to $70 if you get the wide angle holder, which again I recommend). If you find yourself using the Grad ND a lot, you can check out the other filters as well.