A impartial density (ND) filter reduces the quantity of sunshine coming into your lens. Since photographers usually need extra gentle, blocking some gentle seems like a loopy thought. However for lengthy publicity pictures whenever you wish to purposefully introduce movement blur, or for whenever you want an extended shutter pace for video or flash pictures, impartial density filters are sometimes important. On this article, I’ll be reviewing one such filter: the Ok&F Idea Nano-X variable 1-9 cease ND filter. This can be a comparatively inexpensive filter, costing $73 within the 58mm measurement that I examined.
Construct High quality and Options
The Ok&F Idea 1-9 cease Nano-X is made up of two items of glass rotating towards one another. As a variable ND filter, it permits you to management the extent of sunshine discount, which is proportional to the distinction within the angles of polarization of the 2 glass components.
This specific filter is available in a pleasant pouch, and it has a small ribbon on the facet that aids in extracting the filter. It’s a way more sensible resolution than a few of the plastic instances that include different filters that usually pop open. Within the subject, it may be tough to juggle filters, so I appreciated this comfort.
Adjusting the filter’s density is straightforward, and will be performed with the orange tab that stands proud the facet. It’s an effective way to show the filter you probably have gloves on, however it does stop you from utilizing a standard lens hood. Nonetheless, the orange tab will be taken off with a small Torx screwdriver in case you’d desire to make use of a hood. The filter itself has a small arrow that factors to gradations on a scale, making it simple to regulate the extent of darkening.
Vignetting Efficiency
Many filters add a little bit of further vignette, which is often fairly simple to appropriate in put up. I examined the filter on the Olympus 12-45mm f/4 PRO lens at 14mm and 45mm to get a tough thought of the vignetting, and I additionally in contrast the filter towards the naked lens. By dividing the luminosity of a photograph with and with out the filter, I may get an approximate thought of the vignetting of this filter. To see if the density of this variable ND filter mattered, I examined it at each the 2-stop and 5-stop density ranges:
This check is fairly casual, however reveals that the vignetting is minimal at 45mm (90mm FF equal), and a bit extra noticeable at 14mm (28mm FF equal). Additionally, rotating the ND filter for various densities didn’t appear to vary the vignetting in a significant means.
To additional check the vignetting, I in contrast the Ok&F filter towards a set impartial density Hoya filter that I already owned. They appear to have roughly equal vignetting, accounting for the variance of the measurements:
So, the vignetting at wider focal lengths appears about typical for a impartial density filter. It’s not too robust and goes away in put up in case you simply add a bit of additional correction. I additionally shot lots of video with the filter at a wide range of focal lengths, and I didn’t run into any bother with vignetting with the footage.
One factor you do have to bear in mind is that this filter makes use of two mixed polarizing filters with a purpose to obtain the variable impact. Due to this, at some wider focal lengths, you may get barely uneven vignetting throughout your picture, which seems to be form of like this:
I used to be curious if this asymmetry would present up in my measurements, and it did. The attention-grabbing factor is that I didn’t measure any vital asymmetry at 45mm (95mm equal) however measured some at 14mm (28mm equal). Nonetheless, the asymmetry was solely seen when utilizing the filter at a stronger density degree. It confirmed up with 5 stops of ND filtration on this filter, however not with 2 stops. You may see these outcomes under – word, the purple strains blocks the nearly equivalent blue line:
This can be a limitation of all variable impartial density filters, so it will possibly’t be helped. It’s principally not noticeable and correctable, however as soon as you’re round 9 stops, then will probably be noticeable in real-world pictures. Thus, I’d advocate protecting the filter at 8.5 stops on the most. This makes certain you don’t get too near the “X” impact, the place there’s vital unevenness throughout the body.
Listed below are two pattern images taken with pretty even, managed lighting on the five-stop setting after lens correction so you’ll be able to see there’s actually little or no added vignetting on the five-stop setting:
Additionally, with the polarizing glass, you may additionally see a whole darkening of already-polarized gentle, reminiscent of the sunshine coming from pc screens. Once more, this isn’t a fault of this filter however only a limitation of the polarizing glass. That being stated, in case you’re filming or taking pictures in a spot with pc screens, chances are high you’ll be indoors and received’t want an ND filter anyway.
Colour Shift
One other consider selecting a filter is coloration shift. Some filters add a little bit of coloration, whereas others are impartial. Ideally, the filter ought to be as near impartial as potential. Once more, I made a casual check by taking an image of a PDF coloration chart at a set white stability on my display screen, with all lights off. Right here’s the outcome:
The Hoya Filter is pretty impartial, however there’s a slight warming within the Ok&F idea filter. Setting the white stability taking from the identical spot in all three pictures, I measured the share correction required for each white stability and tint:
This reveals that the Ok&F idea warmed the picture a bit (round 500K) and shifted the picture a bit in the direction of the magenta finish of the spectrum. Total, the impact was barely stronger than the Hoya filter. That being stated, after correcting all three pictures for white stability, it was very tough to inform the distinction between the photographs, and in apply the shift is pretty slight. Listed below are the waveforms of all three pictures after correction, exhibiting little or no indicators of everlasting harm from coloration shift:
Total Impressions
Virtually talking, I really feel that the Ok&F Idea Nano-X Variable ND filter is a superb filter. In taking pictures many hours of video outdoors with it, I bumped into few precise issues. True, it does have a slight quantity of coloration shift, however that’s simply corrected. Furthermore, it’s not simple to search out an ND filter available on the market that has such a variety of 1-9 stops. Those that do exist both have a narrower vary of stops or are costlier, generally considerably so. (The Ok&F filter is $73 within the 58mm measurement that I examined.)
So, who’s this filter for? For those who’re a photographer who wants a variety of ND stops, or an individual who shoots lots of video, I believe this filter can be nice. To my data, it’s probably the most sensible and inexpensive filter that has good efficiency. It’s true that mounted filters have just a few benefits, however they’re usually impractical for many who shoot video. Even in case you solely shoot stills, they take extra time to make use of.
For those who’re concerned with shopping for this filter, take a look at both the B&H or Amazon hyperlinks right here. Shopping for gear utilizing our hyperlinks helps help opinions like this at no further value to you!
(Don’t overlook to pick out the right filter measurement.)