Filter Kit: ND1000 + CPL K&F Concept
It is been a few months since I began to use this circular filter kit from a well-known brand K&F Concept. The kit consists of two filters, an ND1000 and a Polarizer (CPL). In my case it is 62mm diameter, it works for (almost) the whole range of Olympus PRO Lenses (brand that I mainly use).
The model, precisely, is the "K&F Concept Digital HD Slim MRC".
The filters are obviously made of metal and good quality glass. They give the sensation of being robust and the thread is precise. The ring nut of the CPL to change the rotation of the polarization plane is sturdy, but perhaps slightly hard and if you have not screwed the filter on the lens properly, if you inadvertently rotate it counterclockwise you run the risk of unscrewing the filter from the target.
Now let's talk about optical quality, and in this article we will deal with the neutral density filter.
The ND1000, for the uninitiated, is a type of filter that "breaks down" the light that reaches the sensor, in theory without changing the final colors of the photographs. It knocks it down a number of times which is precisely the one specified after the letters ND, in this case, 1000. So if in a normal shooting condition the exposure meter at a given sensitivity and a given aperture indicates us as the ideal shutter speed 1 / 1000, with an ND1000 filter to have the same exposure I will have to bring the shutter speed to 1 second at the same ISO and aperture (1 / 1000s * 1000 = 1s).
The feature that most interests me to test in this type of filter is its ability not to introduce too strong dominants and therefore not to alter the original colors.
The test was carried out with an Olympus E-M1 Mark2 and an M.Zuiko 12-40 PRO.
The ideal time dictated by the eposimeter was 1/5000 at 5.6 aperture so 2 photos were taken at 1 / 5000s without filter and at 1 / 5s with ND1000.
The photos were taken with the same White Balance set manually at 5250K. It makes no sense to do this type of test with WA AUTO since the results would be distorted by the machine's algorithms.
1/5000s Without ND1000
1/5 with ND1000
The first thing that catches the eye is the difference in hue of the entire frame. The photo without filter is well balanced while the one with filter is colder. This does not have to worry, absolutely since the WB can be adjusted during shooting or in post production (it should always be done). it is also slightly darker than the original.
I therefore imported the RAWs into Lightroom simply by trying to modify the wb and the exposure. I left the reference photo unchanged (the one without the filter), I modified the WB making it as similar as possible to the reference and slightly raised the exposure (a trifle, about 1/20 stop), obtaining the following:
1/5000s without ND1000
1/5s with Modified ND1000
The two photos are very similar.
You notice first of all a vignetting induced by the use of the filter, but this I don't think depends on the quality of the glass, but on the presence of the filter on the lens.
The photos are almost super imposable, even if zooming 1: 1 with the same area you will always notice a difference in the colors. I was unable to obtain identical colors with just the modification of the WB, a sign of the fact that dominants were introduced, the major one, in my opinion, in the green. Moreover, an ND1000 filter is unthinkable and does not introduce any dominant.
However, not even playing so much in the HSL panel, with subsequent correction of the vignetting, I managed to obtain the following photo which is very similar to the one without the filter:
In conclusion, this K&F ND1000 turns out to be a good alternative to the more well-known filters of the same level, without making particular references to other brands. It is in my humble opinion in a medium range and will certainly not disappoint the expectations of those photographers who want to approach this mouse of photography. If you expect dominant zero, however, I think this product is not for you, but I think that you can do much better in this price range.
I leave you the links for a possible purchase. Kit review of the polarizer will follow.