K&F Concept 100mm ND8 3 Stop Neutral Density Square Filter
I’ve just taken delivery of the K&F Concept 100mm ND8 3 Stop Neutral Density Square Filter to add to my growing collection of K&F filters. As expected, the ND8 arrived in the usual high quality packaging, well protected for transit in it’s sturdy faux leather case with magnetic catch.
[rl_gallery id=”14526″]
So what is an ND8 filter? Neutral density filters are available in different strengths/darkness which reduces by a specific number of stops of light. The filters are labelled in two ways (neither of which is the number of stops!) by Optical Density or by ND Factor. Here’s a simple table that shows the main filters.
Stops of Light | ND Factor | Optical Density |
1 | 2 | 0.3 |
2 | 4 | 0.6 |
3 | 8 | 0.9 |
4 | 16 | 1.2 |
5 | 32 | 1.5 |
6 | 64 | 1.8 |
7 | 128 | 2.1 |
8 | 256 | 2.4 |
9 | 512 | 2.7 |
10 | 1024 (aka ND1000) | 3 |
So, an ND8 filter reduces by just 3 stops of light. As an example, under average day time conditions where we might be getting a correct exposure of 1/125s the ND8 would allow us to drag the shutter out to 1/15s.
Here is a useful grid to calculate the expected long exposure for different ND filters.
So the K&F Concept ND8 filter, based on the extra 3 stops, I decided would be best used to help me capture some minimalist wave photography on a recent visit to Seaham beach on the North East coast of England.
I was shooting on a fairly overcast morning and the correct exposure was 1/4s at f/11 on my Sigma 10-20mm, adding the ND8 pushed the exposure to 2 seconds. 1-2 seconds is a perfect length to capture the gentle motion of the waves lapping on the beach.
As with the other K&F Concept Pro ND filters, the coating is absolutely colour neutral and adds no colour cast to the final images.
Here is a selection of the final images taken on the day.
The K&F Concept ND8 100mm Pro Filter is available from the Kent Faith website and also from Amazon. If you purchase by 30/12/2019 you can also get 10% OFF using the discount code: KF10UK