Exhibiting improved clarity, flatness, and reduced reflectivity, this 37mm Firecrest Ultra ND 1.8 Filter from Formatt Hitech is a neutral density filter providing a 6-stop reduction in exposure. This 1.8 density creates a darkening of the entire image, allowing you to photograph with a wider aperture or longer shutter speed than normally required. By slowing your exposure time or increasing your aperture, you are able to control depth of field and convey movement more easily. Designed using inspiration from their cine Firecrest filters, these Ultra filters receive an additional lapping and polishing process during production to ensure lower reflectivity and improved clarity and sharpness.

The design of this filter has been optimized for use with digital sensors and promote nearly flat attenuation of visible, UV, and infrared light. Due to imaging sensors' greater susceptibility to infrared light, compared to traditional film, color casts can occur when photographing darker subjects that require increased exposure times. This filter provides a high level of neutrality across all three spectrums in order to eliminate color casts and ensure cleaner, truer blacks.

Applied to the outside of the SCHOTT Superwite glass construction is a 15-layer Firecrest multicoating, which helps to minimize reflections and flare in order to maintain truer colors and contrast. The multicoating is also scratch resistant and hydrophobic to benefit the overall durability of the filter. The filter is set within a 5.5mm-thick SuperSlim aluminum filter ring, which features front threads for stacking additional filters or attaching a lens cap.

This filter is designed specifically for photography applications. This filter is not suitable for direct solar viewing with the naked eye, including with optical viewfinders.

1.8 Optical Density    15-Layer Coating on Outside of Filter    SCHOTT Superwite Glass    SuperSlim 5.5mm-Thick, Stackable Ring    Hydrophobic and Scratch Resistant    Darkens Entire Image    Neutral Results Across All Spectrums    Secondary Lapping and Polishing Process

The Firecrest Ultra series filters exhibit greater clarity and have lower reflectivity than the original Firecrest filters. Borrowing from the range of Firecrest cine filters, the Ultra series filters undergo a secondary lapping and polishing process after the initial polishing and bonding stage. This additional step helps to ensure flatness and consistency for improved image quality.

ND 1.8 filter darkens the image, allowing you to photograph with a longer shutter speed or wider aperture than normally required.

Providing a 6-stop exposure reduction, this filter allows you to control depth of field and convey movement more easily.

Attenuates infrared light, as well as visible and UV wavelengths, to maintain color neutrality and suppress color casts due to increased exposure lengths.

The 15-layer Firecrest coating has been applied directly to the outside of the filter glass by way of a vacuum-formed, hard-coated, electrolytic process. The multicoating is water and scratch resistance for greater overall durability.

SCHOTT Superwite glass promotes maintained image clarity and is set within a 5.5mm-thick SuperSlim aluminum filter ring.

Related Questions and Answers

Q: 1. I think I have seen some VND's have a total size larger than its threading part, which ends up blocking the ability to mount a lens hood. Does the size of this filter prevent the mounting of a lens hood?

A: You will be able to mount the lens hood with the K&F Concept Variable Fader ND2-ND400 Filter on the lens.

Q: 2. Is there any polarization effect with this filter?

A: The K&F Concept ND2-ND400 Blue Multi-Coated Variable ND Filter (82mm) reduces exposure, but there is no polarization effect.

Q: 3. I just bought this filter and I experience something weird. When I turn it over the darker ND dot, the filter seems to go even darker and the photo look like a IR shot (all purple). Yesterday I set the filter at his darker point. I took a photo : f.14, 2.5s, iso 100. Then I turn further the filter and it became darker. So I change the time and I hand to go further as 60sec to get proper expose photo.. but in the viewfinder, it was all purple. Is that normal? I use it on Olympus em10II and 14-42 kit lens

A: The K&F Concept ND2-ND400 Blue Multi-Coated Variable ND Filter (58mm) is only rated to perform properly till 8.6 stops. Going beyond the specified maximum may degrade image quality. Additionally with higher levels of light reduction one runs the risk of IR pollution in the image. As you reduce visible light you are more suspect to this pollution, which could be why you are seeing the strange colors.

Q: 4. Are these filters glass or resin?

A: The K&F Concept ND2-ND400 Blue Multi-Coated Variable ND Filter (72mm) is a glass filter.

Q: 5. Does it work in continuous autofocus mode of sony cameras with the Sony FE 28 mm f/2 Lens?

A: If the filter is set to the darker end, that may interfere with the continuous autofocus.

Q: 6. What is the front diameter size of 82mm thread? Does it fit inside Tiltaing Mini Matte Box?

A: The K&F Concept Variable Fader ND2-ND400 Filter (82mm) has an 86mm front diamter. However, please be aware that there are no front threads on filter, therefore you can not connect mattboxes with adapter rings. As for Tilta Tiltaing Mini Matte Box, they only offer adapter rings up to 85mm.

Q: 7. Can this be safely used for photographing a Solar Eclipse?

A: I would recommend 17 stops or more for solar eclipse, so I wouldn't recommend the K&F Concept Nano-X Series ND32000 ND Filter (100 x 100mm, 15-Stop) for solar eclipse.

Q: 8. does it have a 67mm filter thread to stack another filter on top of it?

A: The K&F Concept ND2-ND400 Blue Multi-Coated Variable ND Filter (67mm) will be able hold another filter on top of it, the size of the filter to mount is 72MM.

Q: 9. Does the 5-stop (Ultra slim) filter allow stacking?

A: Yes, the Specifications state the FotodioX Pro 145mm Ultra Slim ND 1.5 Filter (5-Stop) has 145mm front filter threads which should allow you to connect an additional filter that has 145mm filter threads to the front of the filter.

Q: 10. Is there a lens cap for K&F Concept Variable Fader ND2-ND400 Filter (49mm)?

A: The back of the filter is 49mm but the front is 52mm so you can use this 52mm lens cap on it. https://www.bhphotovideo.com/c/product/807037-REG/Sensei_lc52_52mm_Center_Pinch_Snap_On.html