Today we will look at a vari­able ND fil­ter (2–400) from the man­u­fac­tur­er Kent & Faith — Nano‑X.

ND fil­ters are designed for shoot­ing with long expo­sures in the day­time / in good light con­di­tions. They can also be used to shoot wide open to avoid over­ex­po­sure.

Package:

Comes with a case for con­ve­nient and safe trans­porta­tion of the fil­ter. The mate­r­i­al of the cov­er is sim­i­lar to leather, it is sewn qual­i­ta­tive­ly and even­ly, the threads do not stick out. Mag­net­ic case cov­er.

It is worth not­ing that the case has a well-thought-out and con­ve­nient fil­ter extrac­tion sys­tem — you just need to pull the cable.

The weight of the fil­ter is 27 grams.

The K&F Con­cept brand spe­cial­izes in the pro­duc­tion of var­i­ous pho­to equip­ment and pho­to / video acces­sories, such as tripods, fil­ters, var­i­ous adapters for lens­es, pho­to back­packs, and more.

There are var­i­ous vari­a­tions of ND fil­ters in the store (both with a fixed lev­el of dim­ming and with vari­able ones) for dif­fer­ent carv­ings and with dif­fer­ent lev­els of obscu­ri­ty. In this case, we are talk­ing about the ND2-400 fil­ter with a diam­e­ter of 52mm (there are oth­er diam­e­ters).

Let’s test it on a Sig­ma 30mm 1.4 lens (Sony A6300 cam­era). Here’s what it looks like on cam­era:

The fil­ter is made of alu­minum, the assem­bly is of high qual­i­ty.

The rota­tion is smooth and mod­er­ate­ly tight. For more com­fort­able rota­tion, the upper part is ribbed, and there is also a lever. The upper part rotates in both direc­tions, there are no lim­iters (stop­pers).

The low­er part is marked from the small­est to the largest lev­el of dim­ming. Also, this part is par­tial­ly ribbed, mak­ing it con­ve­nient to wind the fil­ter on and off the lens.

The fil­ter lens is water-repel­lent (droplets flow down it and leave no marks, not smudges) and scratch-resis­tant.

If we com­pare the expo­sure val­ue with­out a fil­ter and with its max­i­mum eclipse, the expo­sure decreas­es by at least 4 stops (from +2 to ‑2). Since the expo­sure of the cam­era is dis­played in this dig­i­tal range, it is dif­fi­cult to say the exact num­ber of stops of dim­ming, but approx­i­mate­ly it is some­where around 7–8 stops (the man­u­fac­tur­er claims 9 stops).

The shut­ter speed decreas­es from 1/1500 to 0.5 sec­onds. As for the aper­ture, even the 1.4–16 range is not enough to bring the expo­sure from ‑2 to 0.

When shoot­ing in the scorch­ing sun with an aper­ture of 9.5–11, ISO 100 and a max­i­mum eclipse lev­el, you can set the shut­ter speed to 1–1.5 sec­onds.

If you shoot in the shade (for exam­ple, a stream in the for­est), with an aper­ture of 10 and ISO 100, the shut­ter speed can be increased to some­where up to 20 sec­onds. In some cas­es, in the absence of direct sun­light, the best, even with aper­ture 4–5.6 and ISO 100, I set the shut­ter speed to 30 sec­onds and got a pho­to with­out glare.

Even at max­i­mum eclipse, the image qual­i­ty remains excel­lent, no drop in sharp­ness was noticed.

The man­u­fac­tur­er declared the absence of a “cross” defect. This is how it is if you do not go beyond the markup, but if you hov­er over the posi­tion indi­cat­ed in the pho­to below, the cross still appears (the appear­ance or absence of the cross also depends on which lens the fil­ter is used with).

Photo with / without filter:

Photo examples:

ISO 100, F5.6, shut­ter speed 30 sec­onds

ISO 100, F10, shut­ter speed 20 sec­onds

ISO 100, F10, shut­ter speed 30 sec­onds

ISO 100, F5.6, shut­ter speed 30 sec­onds

ISO 100, F4, shut­ter speed 30 sec­onds

ISO 100, F2.8, shut­ter speed 10 sec­onds

ISO 100, F4.5, shut­ter speed 30 sec­onds

ISO 100, F10, shut­ter speed 30 sec­onds

ISO 100, F10, shut­ter speed 0.70 sec­onds

ISO 100, F8, shut­ter speed 1/6

ISO 100, F8, shut­ter speed 1/45

ISO 100, F11, shut­ter speed 1/15

ISO 100, F11, shut­ter speed 1 sec­ond

ISO 100, F11, shut­ter speed 1.5 sec­onds

ISO 100, F11, shut­ter speed 1.5 sec­onds

ISO 100, F11, shut­ter speed 1.5 sec­onds

ISO 100, F11, shut­ter speed 1.5 sec­onds

ISO 100, F11, shut­ter speed 0.70 sec­onds

ISO 100, F11, shut­ter speed 1 sec­ond

ISO 100, F11, shut­ter speed 1 sec­ond

ISO 100, F6.7, shut­ter speed 30 sec­onds

ISO 100, F11, shut­ter speed 1.5 sec­onds

ISO 100, F11, shut­ter speed 1.5 sec­onds

ISO 100, F11, shut­ter speed 1 sec­ond

ISO 100, F11, shut­ter speed 1.5 sec­onds

ISO 100, F11, shut­ter speed 0.5 sec­onds

Results

• qual­i­ty mate­r­i­al and high build qual­i­ty;
• water-repel­lent and scratch-resis­tant coat­ing;
• excel­lent sharp­ness at any lev­el of dark­ness;
• avail­abil­i­ty of a case for trans­porta­tion;

! the pres­ence / absence of a cross depends on the focal length of the optics used.

You can buy the filter here:

• AliEx­press Offi­cial Store (Coupon CNBFYD9LIRDI reduces the price by $3)
• The offi­cial web­site of the man­u­fac­tur­er (coupon 10kfru reduces the price by 10%, valid until 2021.12.31)