The Natural Night filter is available in most sizes for the NiSi filter holder range including 100mm, 150mm and 180mm. It is also available as a circular filter in sizes from 40.5mm to 95mm.
When using it for cityscapes, ensure that your exposure times are adjusted for the extra stop of light that it blocks. Shoot in RAW so that white balance can be easily adjusted without image degradation. Use the RAW converter of your choice to find the appropriate white balance and tint for each given scene. Common colour corrections for cityscapes include adjusting the reds in the scene using HSL sliders. To achieve great results with the Natural Night Filter in the city, try daylight white balance as a starting point. It’s great to achieve a with and without comparison shot plus get great results with other colours like blues and pinks from the city lights.
When using it for astrophotography, be aware that this filter blocks 1 stop of light. It is recommended that your camera can handle up to 3200iso cleanly to make maximum use of this filter for milky way images. This filter gives a much more natural appearance to the starry sky if shot near towns emanating light pollution. Adjustments to white balance, tint and HSL sliders discussed for cityscapes may also apply.