Reviews
Very nice variable ND filter with minimal color shift at a good price point
I have several neutral density (ND) filters to use with my mirrorless camera, but this K&F Concept 82mm True Color Variable ND Filter is the first with variable ND. Rather than changing filters or stacking filters to achieve the desired level of light reduction, it is only necessary to rotate the filter to vary the level of light. Variable ND filters come in a wide range of price points, and this filter seems to fall near the middle or upper middle of the range. I have several K&F Concept filters and have found them to be high quality, and this variable ND filter is no exception. In addition, this filter also is listed as a true-color filter, without the color shift that can occur with ND filters.
The 82mm threads on filter fit perfectly on my lens. The outer diameter of the filter was slightly larger than my 82mm UV filter, but the lens cap for my lens still fit on the filter. However, I was not able to put my lens hood on over the filter due to the slightly larger outer diameter. I also tried to put the lens hood on first, but it was pretty much impossible to align the filter with the threads on lens and tightening the filter to the lens would have been hard had I been able to get that far. A minor drawback of variable ND filters (or CPL filters) if you manage to install a lens hood, it is awkward and difficult to rotate the filter with the lens hood in place.
I shot a set of pictures at ISO 200 and f/8 aperture priority to check for any color shift. The filter has 13 tick marks between the “MIN” to “MAX” points labeled on the filter. I took a photo at the MIN point, followed by rotating the filter two tick marks and taking another photo, and then continued to follow the two-tick-mark, snap photo pattern. The level of light reduction by the filter is not linear with respect to a constant degree of rotation. The first three photographs all used 1/500 for the shutter speed, and it was not until the fourth photo (6 tick-marks in) that the shutter speed dropped to 1/400. As the tick-marks started to approach the MAX point, I changed the filter rotation amount to one tick-mark for each photo, as the light level was stopping down rapidly. The last two tick marks were taken with a shutter speed of 1/30 and 1/10, respectively, and the MAX point shutter speed at 1.6 seconds. I also took the same picture without the filter in place, to check for any color shift. As far as I could tell there was almost no color shift until the MAX point was reached. The photo taken at the MAX point – f/8 and 1.6 seconds shutter speed – had a very blue cast to it.
To check on the blue shift at MAX, I also tried a second set of pictures of maiden grass blown around in a light, intermittent wind. I again used aperture priority f/8 and ISO 200, and took photos at MIN (1/60 sec), 1-tick under MAX (1 sec), 1/2-tick under MAX (2.5 sec), and MAX (10 sec). The blue tint appears very slightly at 1-tick under MAX, is slightly more pronounced at 1/2-tick under MAX, and again was quite visible at MAX. So, color-shifting with the filter is pretty much unnoticeable until the filter is rotated almost to the MAX point.
Overall, I am quite happy with this variable ND filter. The color shift as the filter stops down is not noticeable until it is almost at the MAX point. When approaching the MAX point there is a blue shift, but the color-shift is correctable in Lightroom or other photo editing applications. The filter appears to cover a 9-stop range as advertised, with most of that range occurring in the upper 1/2 or 1/3 of the filter’s rotation range.
The 82mm threads on filter fit perfectly on my lens. The outer diameter of the filter was slightly larger than my 82mm UV filter, but the lens cap for my lens still fit on the filter. However, I was not able to put my lens hood on over the filter due to the slightly larger outer diameter. I also tried to put the lens hood on first, but it was pretty much impossible to align the filter with the threads on lens and tightening the filter to the lens would have been hard had I been able to get that far. A minor drawback of variable ND filters (or CPL filters) if you manage to install a lens hood, it is awkward and difficult to rotate the filter with the lens hood in place.
I shot a set of pictures at ISO 200 and f/8 aperture priority to check for any color shift. The filter has 13 tick marks between the “MIN” to “MAX” points labeled on the filter. I took a photo at the MIN point, followed by rotating the filter two tick marks and taking another photo, and then continued to follow the two-tick-mark, snap photo pattern. The level of light reduction by the filter is not linear with respect to a constant degree of rotation. The first three photographs all used 1/500 for the shutter speed, and it was not until the fourth photo (6 tick-marks in) that the shutter speed dropped to 1/400. As the tick-marks started to approach the MAX point, I changed the filter rotation amount to one tick-mark for each photo, as the light level was stopping down rapidly. The last two tick marks were taken with a shutter speed of 1/30 and 1/10, respectively, and the MAX point shutter speed at 1.6 seconds. I also took the same picture without the filter in place, to check for any color shift. As far as I could tell there was almost no color shift until the MAX point was reached. The photo taken at the MAX point – f/8 and 1.6 seconds shutter speed – had a very blue cast to it.
To check on the blue shift at MAX, I also tried a second set of pictures of maiden grass blown around in a light, intermittent wind. I again used aperture priority f/8 and ISO 200, and took photos at MIN (1/60 sec), 1-tick under MAX (1 sec), 1/2-tick under MAX (2.5 sec), and MAX (10 sec). The blue tint appears very slightly at 1-tick under MAX, is slightly more pronounced at 1/2-tick under MAX, and again was quite visible at MAX. So, color-shifting with the filter is pretty much unnoticeable until the filter is rotated almost to the MAX point.
Overall, I am quite happy with this variable ND filter. The color shift as the filter stops down is not noticeable until it is almost at the MAX point. When approaching the MAX point there is a blue shift, but the color-shift is correctable in Lightroom or other photo editing applications. The filter appears to cover a 9-stop range as advertised, with most of that range occurring in the upper 1/2 or 1/3 of the filter’s rotation range.
22/12/2024