This spring Nisi Filters announced its Medium GND filter. Simply put, it is a metamorphosis of a hard edge and soft graduated filter. A hard edge filter is most convenient when one is shooting an ocean scene with a very defined horizon line, whereas a soft grad will be most useful in an environment with a more messy horizon – like for instance when we have trees or a forest protruding into the sky.
All the aforementioned filters main objective is to balance an exposure notably during sunset or sunrise when we have a relatively bright sky whereas the ground in comparison is considerably darker. In other words, a filter aims to cancel out or alleviate the limitations of a camera sensor in terms of dynamic range.
The new medium filter in many ways replaces both the hard and soft grad since it can be used for both ocean and rural scenes. Note that the medium filter has a much shorter transition zone than a regular soft grad filter which transition goes from the middle and becomes linearly darker towards one of the edges.
The medium filter has several advantages: It is far easier to “find” the transition line in an ocean scene. In other words, one do not have to be super careful with matching the lines as with a hard edge filter. Further, a sky isn’t linearly brightened towards the top of the camera frame so that a regular soft grad filter is a tad counter-intuitive in regards to the conditions we face out in the the field. This means that the medium filter in most instances will do a better job in balancing a sky than a regular soft filter.
The top left shows a traditional graduated soft filter and we see how the transition zone from transparent to dark stretches across the filter’s top half as opposed to the Medium filter (top right) which only have a modest transition zone in the middle.
In the example image above the medium filter did a great job in balancing the strong light in the sky, that is, light rays from the sun which itself was obscured by clouds. Yet, I had no problems with bringing out sufficient shadow detail in whatever was protruding into the sky and thus covered by the filter. The image is edited in Lightroom and Photoshop.
As with all Nisi filters the optical quality is very good. There is no loss of detail, no color cast, no vignetting and so on. And the filter comes with all the coatings with which Nisi furnishes its filters.
Personally I prefer to insert filters into the filter holder when the camera is in live-view mode. That makes it much easier for me to assess the effect the filter has on a scene and how far down I have to push the filter to achieve the desired effect.
We will now have a look at three sample images; one without filter, one with the medium filter and one with a regular soft grad. Both the medium and soft grad are 3 stops. The images are shot during daytime with the sun behind me so that we do not exactly have a high contrast scene, but the three exposures are not subject to rapidly changing light conditions which often is the case during sunset or sunrise. All images are straight out of camera (sooc). The camera was set to average metering and all three are shot at what the camera suggested as zero, that is, no exposure compensation in either direction. Along with the sample images I also provide the sooc histogram.
The first image is shot without any filters:
The Next image is shot with the Medium filter:
The last image in the series is shot with the 0.9 graduated soft and the filter was pushed almost all the way down in the filter holder:
Conclusion: It should be self-evident from the images and histograms that the Medium filter does an outstanding job in protecting a ton of highlight detail which one can play with in the post process work. One can also read from the sample images that the Medium filter protects the highlights better and provide a more balanced histogram than the 0.9 soft grad filter.
Disclaimer: This is by no means a scientific test which checks all the boxes as we expect a well carried out scientific test to do, but the sample images shot under relatively equal conditions should provide a good indication on what we can expect from the Nisi Medium filter.