Looking for gradient filters? I’ll show you which strengths you need, why I recommend plug-in filters and which filters are color accurate.
Contents
Here is a very detailed article about gradient filters. If you don’t want to read it all, here’s my quick overview.
Keep in mind that for each of these systems you still need a matching filter ring for your filter diameter and the filter holder for that system.
Dynamic range – why do I need gray graduated filters at all?
A modern digital SLR camera does not see like the human eye. Today’s best SLR cameras are good, but the human sense organ is still far ahead of even these cameras. The visual apparatus can detect large differences in brightness without any problems. If you look at a landscape, you see details in the landscape itself and also in the sky. This seems completely natural to you, because you don’t know it any other way. If you photograph the landscape with a camera and have sky in the picture, it often happens that the sky in the picture is very bright or just white. Brighter than one has perceived it with the eye. The other way around it can happen that the sky is shown in the picture as you have seen it, but the landscape is much too dark. The camera can handle differences in brightness within a picture worse than the human eye. The indication of how much brightness differences in f-stops a camera can handle is called dynamic range. At the same time, you can say that scene XY has 15 f-stops dynamic range. Good DSLR cameras have 13 f-stops dynamic range. To deal with this shortcoming, there are gray graduated filters. Gray graduated filters are also called graduated filters. These filters are primarily used in landscape photography.
Gray graduated filters have not just been around since digital photography, but way before. The problem of the lack of dynamic range cannot be compensated with image processing, unless you work with several exposures. If there is no more drawing in the corresponding image area due to overexposure or underexposure, you can’t save anything even with the RAW format.
The gray graduated filter is not to be confused with the ND filter, which you need for long exposures.
Structure of gray graduated filters
A gray graduated filter is neutrally darkened in the upper part. There it lets less light through, but ideally without affecting the color. In the lower part it is transparent. In between there is a transition, depending on the type. This transition is always a straight line.
Material
Graduated gray filters are usually made of poly-resin or glass.
Gradations – the different strengths
A distinction is made according to how much the upper part of the filter darkens. The information about the strength is given in f-stops. The most common filters are those with 2 and 3 f-stops. But filters with one or four f-stops also exist.
ND specification Darkening in f-stops
ND 0.3 1 f-stop
ND 0.6 2 f-stops
ND 0.9 3 f-stops
ND 1.2 4 f-stops
Transitions
The transition of gray graduated filters from the dark to the transparent area can be differently hard or soft.
Reverse gray graduated filters are a special feature. For landscape shots in certain light situations it is suitable that just above the horizon is the brightest part of the picture. As an example, imagine a cloudy sky with a strip of light shining through exactly between the landscape and the cloud cover. If you were to use a normal gray graduated filter here, the upper part of the clouds would be darkened too much. To counteract this, there are filters that have the strongest darkening directly above the transition and are somewhat less darkened again towards the top.
Which strengths and transitions of gray gradient filters I recommend for a start
For the first own filters I recommend the strengths ND 0.2 and 0.3, each in hard and soft transitions. In total 4 filters. Exactly these 4 filters are the ones I use most often.
Screw filters and plug-in filters
Newsletter Lead 4 – Photo EquipmentOn the market there are gray graduated filters as screw-on and plug-in versions. The biggest disadvantage of screw filters is that the line of transition cannot be moved. But since you place the horizon in different places in your own pictures, you would have to carry a larger selection of the screw filters. Therefore, the plug-in filters have prevailed. With a filter adapter ring, one attaches a plastic plug-in filter to the lens. The rectangular filters can then be inserted into this filter holder. Depending on your needs, you can slide the filter up or down to position it appropriately for the image composition.
Sizes
Depending on the lens and sensor size used, the appropriate filter size must be selected. The manufacturers have different series in the program and give recommendations for which camera with which lens which filter size is suitable. Cokin, for example, has the A,P,X and Z series in its range:
A series: for filter thread diameters from 36 mm to 62 mm, filter size 67 x 67 mm.
P series: for filter thread diameters from 48 mm to 82 mm, filter size 84 x 84 mm
Z-PRO series: for medium format cameras and film cameras, filter size 100 x 100 (150) mm
X-PRO series: for medium and large format cameras and film cameras, filter size 170 x 130 mm
Source of Cokin filter sizes: Wikipedia
For which filter thread diameters are gray graduated filters available?
For all rectangular plug-in filter gradients, a filter adapter must be used. this must be attached to the lens with the adapter ring. Adapter rings for gray graduated filters are available in all common sizes, for example 82mm, 77mm, 72mm, 67mm, 62mm, 58mm, 55mm, 52mm and 46mm.
Normal and Slim Filter Holder
Newsletter Lead 2 – Popular PostsMost filter system manufacturers offer filter holders with 3 slots. Some brands offer filter holders that have only one slide-in or where the slide-ins can be varied using screws. For example, I use a P filter holder from Cokin and also a Slim P filter holder from Cokin. In most cases I only have one filter in front of the lens. With the Slim filter holder, I can ensure that no vignetting occurs on my wide angle, i.e. the filter holder does not protrude into the image.
Limitations of gray graduated filters
Gray graduated filters, as mentioned above, always have a straight line as a transition. But if the horizon line in the image is not straight, the landscape will be darkened there. An alternative can be to make several exposures with different brightnesses. These are then combined by image processing. This method, however, reaches its limits when there are moving objects in the image. In addition, you spend significantly more time in front of the computer with multiple exposures.
Color Accuracy
Unfortunately, very few filters available on the market are completely color accurate. Cokin is said to have a slight magenta cast, Hitech a slight blue cast, and so the list goes on. Even the most expensive manufacturers are not without color cast.
The problem is not so much that the manufacturers cannot use a neutral substance for darkening. In the place where darkening is done, more light hits the filter-lens-camera construction in the same amount of time. Modern cameras have an infrared blocking filter to keep light at infrared wavelengths from reaching the sensor. The result would be color-distorted images. The same effect occurs with the gray graduated filter. Due to the darkening, a longer exposure time is necessary. More infrared light reaches the sensor than without the gray graduated filter. This phenomenon then causes color shifts that are perceived as a color cast.
Update 18.02.2016: I have now heard from several sides that the Hitech Firecrest filter series is supposed to be very neutral. So far, I have not had any experience with them myself. If someone uses these GNDs, I would be pleased about a few short experiences by mail.
Can I reproduce gray gradient filters with Photoshop? – the digital gray gradient filter
There is the possibility to make several exposures from one scene. Of course, this assumes that the scene and the camera position do not change. In sum, this means that you have to work with a tripod. If the landscape is then also not too much in motion, you can achieve good results with this variant. The different exposures are then merged in Photoshop using masks. This method reaches its limits when elements are in motion during the exposure. A typical example is photographing by the sea, where there are waves in the foreground of the image. individual waves and water waves then make it difficult to put several exposures together cleanly on the computer. After my last trip to Mallorca, I know again that both multiple exposures and gray graduated filters each have a raison d’être.
Gray graduated filters versus Exposure Blending
Last summer I had the opportunity to review Singh-Ray filters directly against multiple exposures (bracketing).
You can see that even a highly upscale gray graduated filter is not color accurate. Both images were developed with daylight white balance in the RAW converter. Besides the color cast, the second reason I don’t use gradient filters is the lack of flexibility. If the horizon is not straight, as it often is in the mountains, for example, the filter will darken parts of the image that I don’t want to darken. The disadvantage, however, is that you have to compose the images on the PC and therefore need much more time for post-processing. Difficult light situations with backlight and haze can easily increase this time to several hours. In the end, I think that both gray graduated filters and working with multiple exposures have their raison d’être. There are light situations where you can get faster and better results with gray graduated filters, other situations with very high contrasts can practically only be accomplished with exposure blending.
Using gray graduated filters correctly
The use of gray graduated filters requires some training and experience before you can achieve reproducible good results. Fortunately, with today’s digital cameras, you can see the results immediately and correct them accordingly. There are two points to consider:
Choosing the right strength. Before shooting, you need to assess how much contrast range the scene has and which gray graduated filter to choose accordingly. If you choose a filter that is too weak, you will lose the bright or dark areas. If you choose too strong a filter, the result may be unnatural or lack contrast.
Place the transition correctly. This is the part that requires some practice. In most cases, the lower part of the darkening sticks out a bit over the landscape to create a clean transition. I recommend here to just try a lot yourself and get a feel with it. If you are not in a landscape worth photographing, it can be worthwhile to go out in the evening after work and practice using the filters in the area.
Example images
Comparison with and without
Follows
Comparison of gradations and transitions
Here comes soon my comparison between different gradations and transitions
Why I advise against cheap gray gradient filters
At Amazon there are sets of gradient filters with 15 filters, filter holder and adapter rings for about 30 Euro. I advise against buying these cheap filter sets. I have not had good experiences with the quality of these filters. Blur, color shifts in the individual channels and lack of color accurate are typical problems. If you buy lenses for several 100 Euro, so that you have good image quality and then this image quality becomes invalid with cheap filters, you have gained nothing. Effect is after a few weeks that you are dissatisfied, then ordered the brand filters and ended up paying twice.
Gray graduated filters review & comparison – which ones I already used – my recommendations to buy gray graduated filters
Small Budget – Cokin Graduated Gray Filter Sets
For starters, I recommend filters from Cokin. Even though these are not 100% color accurate, you can still get good results with them. The magenta cast can also be used deliberately as an effect.
Cokin also offers ready-made filter sets, which can save you a few euros. Don’t forget to order the appropriate filter adapter ring for your lens!
Medium budget – Formatt Hitech gradient filter sets
With Formatt Hitech Graduated Gray Filter Sets you get gray graduated filters that are largely color neutral.
Big Budget – Lee Graduated Filter Sets
Professionals will reach for gray graduated filter sets from Lee or Singh-Ray.
Other manufacturers I have not yet reviewed
In addition, there are many other manufacturers of gradient gray filters and entire sets: Haida, B+W, Hoya, Hama, Tianya, Heliopan and Phottix.
Can you recommend a particular store for gradient gray filters?
You used to have to search the net to even find stores that had the filters you wanted, now you can get almost anything on Amazon.
I have a Canon or Nikon camera, is there anything specific I need to consider when buying gradient filters?
No, the gradient gray filters are independent of the camera brand, so they can be used with any manufacturer.
Is there a difference between gradient gray filters and graduated filters?
As the name suggests, both are graduated filters. Graduated gray filters go from gray to transparent. However, there are also filters that gradient from a specific color to transparent. In the 80s, for example, the tobacco graduated filter from Cokin was once very popular. Today, however, colored graduated filters are hardly ever used, because this effect can be recreated on the computer with very little effort.