The Kase trademark: The quality
Some filters are already available for a few euros, others cost over 100 euros. The biggest differences are in the quality of the glass and the material. The thinner the glass, the more expensive it is to produce, but the quality of the filter also increases and so does the quality of the images taken. Glass that is too thick can cause shadows to be cast on the image area. In addition, very cheap glass is often not completely flat and therefore does not refract the light evenly, which sometimes leads to unusable results. Furthermore, all our glasses are anti-reflective. Although this also leads to a higher price, it is usually worth it, especially with frequently used filters. It makes sense to pay a little more for ND, GND or polarising filters and to pay attention to high quality. Furthermore, our filters are all made of optical glass, which reproduces the colours of the pictures neutrally.
The individual components of our filter kits
The grey gradient filter and how it works
Graduated grey filters (GND filters) are a special type of graduated filter that are transparent at one end and darkened at the other. In the middle of the filter, the two surfaces converge, from clear to dark. This transition varies depending on the type of GND filter. The different types are described for you below. These filters are primarily used to balance the exposure of a scene, which in landscape photography naturally consists of a dark section (foreground) and a light section (sky). The human eye is able to visualise a much larger range of light and shadow than a camera's sensor can. This is called the "dynamic range" of a scene. Since the camera covers a smaller dynamic range, using GNDs helps to capture the dynamic range of a scene with one exposure, rather than stitching together multiple shots with different exposure times in post-processing.
How do the types of GND filters differ and when should they be used?
Soft GND filters
These filters have a very soft transition from translucent to dark. They are suitable for scenes that have a wide or interrupted transition from the sky to the actual foreground. An example of a scene that should be shot with a soft GND filter is a mountain landscape that crosses the horizon line. A rock formation in the sea is also predestined for photography with the help of a soft GND filter.
Hard GND filter
These types of GND filters have a hard transition from clear to dark. They are suitable for scenes that have a highly visible transition from the sky to the actual foreground. This filter is most useful to use in landscape shots where there are no elements overhanging the horizon, such as shots of the sea with a wide view of the ocean. These filters can also be used when a hard transition against the sun is advantageous.
Reverse GND filter
Reverse GND filters with a "reverse transition" are similar to the hard GND filter except for the fact that the darkest part of the filter is in the centre. These filters are for shots taken against a light source where the light is most intense on the horizon.
Is there a difference between grey graduated filters and graduated filters?
As the name suggests, both types of filters are graduated filters. Graduated grey filters go from dark to transparent. However, there are also filters that go from one colour to transparent. In the 80s, for example, tobacco graduated filters were very popular. Today, however, graduated filters with a coloured gradient are hardly ever used because this effect can be recreated on the computer with little effort.
How to master difficult lighting situations with a grey filter
The grey filter works like a pair of sunglasses for the camera. If you attach it to the lens, the light hitting the sensor is reduced. Each grey filter has a certain strength, which indicates by how many f-stops it reduces the incident light. This makes it possible to take long exposures and create the following effects:
- make the water of a stream or ocean waves look velvety
- interesting effects can be created with waterfalls or a lake
- in city photography you can make people "disappear" with the help of a grey filter
- make clouds move in the picture (wiping effect)
- in very sunny areas, you can take good-looking pictures.
How can the exposure time for a grey filter be determined without a table?
If you don't have the table in your head or with you, it is relatively easy to calculate the exposure time in your head:
Here is the calculation for an ND 1000 grey filter. Such a grey filter has a neutral density of 3 and thus has a light reduction of 10 f-stops. If the exposure time without a grey filter is 1/25 second, the time must be doubled ten times for a filter with a neutral density of 3.
- 1/25 second x 2 = 1/13 second
- 1/13 second x 2 = 1/8 second
- 1/8 second x 2 = 1/4 second
- 1/4 second x 2 = 1/2 second
- 1/2 second x 2 = 1 second
- 1 second x 2 = 2 seconds
- 2 seconds x 2 = 4 seconds
- 4 seconds x 2 = 8 seconds
- 8 seconds x 2 = 16 seconds
- 16 seconds x 2 = 32 seconds
Whereby an exposure time of 32 seconds is not "normal". The value to be set would therefore be 30 seconds. The same principle can be applied to the other strengths. There, the exposure time is not doubled 10 times, but 6 times for an ND 64 filter.
The versatile polarising filter
Another important type of filter that you should not do without is the so-called polarising filter, which is also known as a polarising filter and CPL filter. Polarising filters make it possible to remove unwanted reflections from various surfaces such as glass, grass, water and leaves. For meadows and trees, it provides a higher contrast and richer landscape. The effect is not always the same and depends on different factors. For example, the CPL filter can be rotated on the lens to change the intensity of the effect. The effect itself is caused by light waves oscillating in a certain direction. This direction is also called the polarisation direction of the light. A polarising filter is coated in such a way that it only allows light of a certain polarisation to pass through. This means that it absorbs about 2 f-stops of light, but at the same time reduces unwanted reflections.