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Hoya HD Square Filter System and IRND Square and Grad-S Filters - 0.9 (3 Stops)

Updated: Aug 31, 2022

I recently had the pleasure of collaborating with Hoya to test out their square filter system and IRND 3 stop and Grad-S 3 stop filters. Hoya is a brand I'm very familiar with as I have used their CPL filter on my camera for many years. I thank Hoya for this collaboration.

Who are Hoya Filters ?

Establishing themselves as Japan's first speciality manufacturer of optical glass, Hoya has diversified itself into new business areas that exploit the potential of advanced optics technologies. As part of the Kenko Tokina Co.Ltd which manufactures everything from binoculars, microscopes and photographic accessories, Hoya delivers filters around the world.



The box containing the square filters was well packaged and filled with scrap paper in order to protect the filters. There was a large sandwich bag filled with scrap paper in it and each square filter came in a plastic sleeve. Maybe this additional plastic isn't necessary but the presentation is excellent.

I received three boxes from Hoya; the square filter kit, the IRND8 (0.9) 3 stop and IRND8 (0.9) GRAD-S 3 stop filters.


What's in the box?

Each box contains an individual pouch for each product. The filters came wrapped in craft paper as well. Each product is very well protected and you can be reassured they won't get damaged in your bag.

Square Filter System

The square filter box comes with a well built pouch that contains the metal holder and two geared adapter rings, a 86mm to 82mm and a 86mm to 67mm, which I used in to fit to my largest lens on the camera. For this I had to specify which adapter I would require. I was surprised to find a 86mm CPL filter, maybe I missed that it is included in the product description. You could use this lens to double up your ND filter to help increase the contrast in your shots. I found the metal holder to be really sturdy and easy to set up. I was ready to go in no time.

IRND8 (0.9) 3 Stop filter

This square ND filter (100mm x 100mm) comes in a neat pouch that has a magnetic lid to keep the filter safe. I do like that the filter pouch comes pre-labeled in order to help those who have multiple filters to keep it all organised and easy to find.

IRND8 (0.9) GRAD-S 3 stop filter

This graduated filter (100mm x 100mm) also comes in a well made pouch but is slightly longer due to being a rectangular shape. As with the square filter mentioned above, the pouch comes pre-labeled.


What is an ND filter?

In simple terms, a neutral density or an ND filter is a filter that is placed in front of a lens to reduce the amount of light making its way to the camera. Think of the ND filter as sunglasses for your camera - although these "sunglasses" do not change the colour of the light being captured, hence the title of neutral.

The classic use of an ND filter is to reduce the shutter speed of your camera in order to create motion blur or emphasise motion in subjects such as waterfalls, clouds, water, smoke and vehicle traffic.

The ND filter also allows photographers to shoot in bright daylight conditions with wide angle apertures without the fear of overexposing.

The ND number relates to the amount of stops (the amount of light) that is being reduced to reach the sensor of the camera. These specific ND filters reduce light by 3 stops.

"A stop is a doubling or halving of the amount of light let in when taking a photo. For example, if you hear a photographer say he's going to increase his exposure by 1 stop, he simply means he's going to capture twice as much light as on the previous shot." -

Adapter Rings

The adapter rings needed to attach to your lens are sold separately so make sure to order what the adapter that you require at the same time.

The adapter ring connected with my lens with ease and it felt sturdy. If you have multiple lens that you are going to work with at a shoot, I would recommend screwing on all the required adapters beforehand in order to save time whilst swapping or if there is one lens that you normally use with the adapter ring you can leave the adapter ring attached to the metal holder in your bag.


Metal Holder

After you screw on the adapter ring onto your camera, the next step would be to attach the metal holder that holds the huge 100mm ND filters. First you place the holder onto the adapter ring and then turn the silver screw on the side until it is held in place. You may wonder what the black sponge strip gasket on the metal holder is for, it's there in order to prevent light leaking into the camera which will ruin your long exposure shots. I found the fit of the adapter ring to the metal holder to be well fitted and I was not concerned that it would fall off any any point.

There is also a polariser control wheel on the side, which you use to rotate the polariser in the metal holder which helps control reflection and saturation. I particularly found this feature to be really useful. So it's possible to just use the polariser with the metal holder or in fact on its own.

The metal holder also contains two slots so you can accommodate two filters at the same time if you so wish, technically you could use the polariser and two filters as well.

The Polariser Filter above


The ND Filters

IRND 3 Stop Square ND Filter

Now we get to the headline act, this ND filter reduces the light by 3 stops which is not a lot compared to other filters but its enough in order to get motion blur even in broad daylight. This filter is made from toughened glass which means it can withstand harsh conditions during your travels. Nano coating on both sides of the optical glass remove light contamination but also ensure that a neutral colour balance is achieved so you don't get the dreaded colour casting which will ruin your images.

I was impressed with the thickness of the glass (2mm). It feels really sturdy and I didn't feel like it would break easily. Additionally, the water repellent and anti-reflection coasting reduces the chances of light reflections aswell as increasing the light transmission. From my tests out in the field, I can confirm that there were no issues of light reflections and colour casting.


IRND Grad 3 Stop ND Filter

I was really excited to test out this lens as I have not used a graduated ND filter before. What initially caught my attention was the immense size of it, 100mm x 150mm. It takes up quite a lot of space in my camera bag.

What would you use it for?

When you have an unbalanced scene, such as really bright sky but the bottom of your frame is dark, graduated filters become essential in order to balance the luminosity of the overall composition without having to do a bracketed shot.

When placed in the metal holder, the grad filter can be rotated to allow any angle to be used, for example if your strong light source is coming from the right, you can rotate the grad filter to the right part of your scene in order to balance the light in the camera. Also with the extended length of 150mm, it allows the filter to be placed wherever you like in the frame allowing for endless possibilities of composition.

The grad filter is made of the same toughened glass and has the same qualities and coating as the previously mentioned ND filter.


Real World Tests

So calculating your shutter speed with ND filters can often require you to do some maths but due to this filter being only 3 stops of darkness, you can easily use aperture priority mode to achieve the desired shot. If you prefer to dial in your shot manually you need to:

  1. Compose and Focus - Find the composition you want, let autofocus do its thing and then switch your camera to manual focus instead. This is because once you put on the filter, your camera's autofocus will start hunting around to focus and it will mess up your shot.

  2. Get the Right Exposure - Whilst finding your composition find your baseline exposure (without the filter on). You will use that exposure to dial in what you will need with the filter on.

  3. Put on the Filter - Now the easy part, put on the filter, trying to not to touch any part except the corners.

  4. Calculate the Maths - Now that we have reduced the exposure by 10 stops, we need to increase the shutter speed by 10 stops.There are three ways to do this:

  • 30 clicks of the exposure dial

  • Multiplying your baseline shutter speed by 1000 (e.g. if your shutter speed is 1/200, you divide 1 by 200 and multiply by 1000 equalling 10 seconds)

  • Simply using an app to work it out

BE AWARE: If you get a shutter speed of over 30 seconds, you should use a remote or app if your camera manufacturer has one as most cameras don't offer an in built control over 30 seconds.

Great apps to workout your shutter speed include:

  • LEE Filters - Stopper Exposure. Photo & Video.

  • MyGearVault. Photo & Video.

  • Perfect Exposure. Photo & Video.

  • The Photographer's Ephemeris. Photo & Video.

  • Digital DoF. Photo & Video.

  • NDExposure. Photo & Video.

With the knowledge above, I set out to use the filters and here are the results.

IRND 3 Stop Square Filter

Even in broad daylight, I was able to achieve motion blur with the water. I had to bump up the F stop up to F22 but I was still able to get a useable image. Very impressive and easy to use.

With the ND Filter, I was able to retain a lot more of the highlights in the shot without bracketing.

IRND Grad 3 Stop ND Filter

I was really impressed with how much detail was recovered in the sky with this filter even in broad daylight without having to bracket the shot (taking two photos and then blending them together), this involves more time shooting and editing. You may not get the silky smooth water with this filter but I really love the results.

I was able to retain the highlights a lot more with the Grad-S Filter in the second shot. I was really happy with the result.



Having used Hoya filter products for a few years, I expected the products to be of the highest quality and my expectations were exceeded. Everything was built extremely well and was super easy to use.

This type of photography may not be everyone as it's more time consuming than point and shoot but I do suggest you give it a try. You often get sharper shots and better compositions as you have to think more about your shots, you may surprise yourself with the results.



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