Review – URTH Square Filter Holders 

Introduction

Urth (formerly Gobe) released its range of Square ND Filters in 2019. In fact, we tested them while we were in Fiji in February 2020 which was our last time overseas before being imprisoned ‘Down Under’ due to Covid-19.

So, we were thrilled when, in July 2021, they finally released their Square Filter Holder along with many new products in July 2021. We were especially interested in testing the 100mm Square Filter Holder to see how well the built-in rubber gasket performed. We have never encountered a holder with a gasket already integrated into it. Other brands usually attach these to the back of the Square ND Filter, and in the past, we’ve had to attach a NiSi Filters gasket to the back of some Urth Square ND Filters to avoid light leaks when taking long exposures.

In this review, we’ll also compare it to the NiSi Square Filter Holder, however, please keep in mind that we still have the original V5 NiSi Square Filter Holder.

Urth, as usual, was kind enough to send us the 100mm Square Filter Holder for this review. Although we received the filter free of charge, this post is an unbiased review. Please read our disclaimer at the bottom of this post.

What is a Square Filter Holder?

In a nutshell, a Square Filter Holder is a product that is designed to be attached to the front of a lens by way of an adapter ring to mount a Square Filter (although technically speaking the only real square filter is the ND Filters). Generally speaking, filter holders can hold up to three square filters and a C-PL filter simultaneously. Due to their design, they rarely cause vignetting in an image even when three filters are combined. A standard 100mm Square Filter Holder that holds 100x100mm (ND) and 100x150mm (Graduated) filters will be suitable for most lenses, however, some extreme ultra-wide-angle lenses will require a customised Square Filter Holder to accommodate the extreme angle of view and will require larger filters. Most Square Filter Holders will also allow you to insert a C-PL (Circular Polarizer) Filter and rotate independently from the Square Filters. For smaller mirrorless systems that use lenses smaller than 67mm, you may also want to consider a 75mm Square Filter Holder (now discontinued) that can accommodate the same amount of filters but the filters are smaller and cheaper.

Quite frankly, a Filter Holder is nothing more than an accessory that allows you to stack filters on the front of a lens. As long as it is well-made and easy to attach to the lens, all filter holders are created equal, no matter what brand. Some may have a few ‘bells and whistles‘ such as a way to lock the filters in place or maybe a different method of inserting the filter, or even a built-in gasket. Regardless, the most important factor is to make sure you place good-quality filters in the holder.

Why use a Filter Holder?

Square Filter Holders are a staple in almost every serious landscape photographer’s bag, but you don’t need to use one if you solely use ND Filters to take long exposure images, or ND Grads to balance the exposure. You would be better off investing in a Circular ND or Circular ND Grad filter. However, using a Square Filter Holder and filters is the obvious choice if your objective is to combine ND Filters with an ND Grad Filter and perhaps even a C-PL filter simultaneously. Alternatively, you can stack Circular Filters, but it is not ideal and certainly not advised on ultra-wide-angle lenses due to excessive vignetting.

A Square Filter Holder will also give you a lot more flexibility with your composition when taking a shot with an ND Grad Filter. Because you can adjust the filter in the holder, it allows you to properly align the filter with the horizon or the brightest area of the composition without adjusting the camera’s position. A circular ND grad filter mounted on a lens is not adjustable, so you need to position your camera to ensure that the filter is aligned with the brightest area of the scene. However, this optimal positioning may not always fit the composition you desire.

Additionally, it depends on the kind of photography that interests you. As travel photographers, although we do use our Square Filter System for tripod-mounted shots, we mostly use the less cumbersome option of Circular Filters for handheld shots.

When would you use a Square Filter Holder?

As mentioned above, a Square Filter Holder and filters are almost exclusively used in Landscape Photography, or at any time when taking tripod-mounted shots that require multiple filters to be stacked. If you want to avoid any vignetting in your shots when using multiple filters, then a Square Filter Holder is the solution.

The URTH 75mm & 100mm Square Filter Holder

The URTH Square Filter Holder was only released in mid-2021, so it is a bit of a latecomer to a very competitive market. Having said that, Urth used its very successful circular filter business as a launch pad into the Square Filter market. It was only a matter of time before they progressed in this direction.

The filter holder arrived in a robust mid-grey recyclable box. All URTH-branded products are now packaged in the same mid-grey colour. Every purchase funds tree planting in areas affected by severe deforestation — revitalising ecosystems and empowering local communities.

Inside the box, the Square Filter Holder is securely held in place by recyclable black square packaging.

The filter holder is constructed with Magnalium, an aluminium alloy comprising 5% magnesium and 95% aluminium, making it much stronger. The filter holder is convex-shaped and sleeker looking than the current NiSi Filter Holder, which is octagonally shaped (NiSi V7 Holder). You will also notice that there are no protruding locking knobs on the side of the holder except for low-profile dials on both sides that control the rotation of the C-PL (Circular Polariser) if it is being used.

Compared to our NiSi Square Filter Holder V5 (sorry, we can’t compare it to the V6 or V7 holders), it is slightly wider but smaller in height.

The filter holder can simultaneously accommodate a Circular C-PL Filter and two 100mm Square Filters (sold separately). Alternatively, if you have the 75mm Square Filter Holder (now discontinued) it will hold a C-PL and two 75mm Square Filters (now discontinued). This is one slot less than most holders, but most photographers rarely use three slots. If you commonly use three square filters simultaneously, the Urth Filter Holder will not suit your needs.

Because the URTH Square ND Filters are not provided with an attached rubber gasket to eliminate light leaks, the filter holder has a built-in rubber gasket on the edge of the inner rim. This added feature is not required if only using a Square ND Graduated Filter, but it is essential if taking fairly long exposures when using the Urth ND Filters. We had the issue of light leaks when using the GOBE Square ND10000 13-stop filter (now discontinued), but a spare NiSi rubber gasket applied to the back of the filter fixed it immediately. Our only concern at this stage is whether the built-in rubber gasket in the Filter Holder will remain in place over time with continual use. Only time will tell, although URTH does offer a Lifetime Warranty on the product.

Please Note: If you are using another brand of Square ND Filter that already has a rubber gasket applied to the rear of the filter, you may have to remove this if the filter is too tight in the first slot. As a result of the built-in rubber gasket, it is extremely tight when inserting a Graduated ND Filter into the first slot due to the friction. If you are only using a Graduated ND Filter then you may want to consider using the filter in the second slot.

The Urth Filter Holder also has a lock on the back of the holder. This locks the adapter ring once attached to the holder. The holder also includes the standard 86mm adapter ring. When ordering the Filter Holder make sure that you order the appropriate 100mm adapter rings or 75mm adapter rings (sold separately) to fit all lenses that you will be using with the Filter Holder.

Lastly, as mentioned previously, there are two low-profile geared wheels on the left and right sides of the holder that operate the rotation of the C-PL if attached. 

Vignetting

We tested the filter holder on a Full Frame sensor camera with our ultra-wide-angle Laowa 15mm f/2 Zero-Distortion lens and found no vignetting, however, once filters were added there was some darkening in the corners although no more than our NiSi V5 Square Filter Holder.

Attaching the Square Filter Holder

Everyone will have their own method of attaching the filter holder to their camera. For us, we have found below is the easiest way.

1. Always remove any circular filters attached to your lens
2. Attach the correct size adapter ring to the front of your lens
3. If you are using the C-PL filter (sold separately), then remove the supplied 86mm Adapter Ring from the Filter Holder. The C-PL filter is 67mm (75mm Square Filter Holder) or 86mm (100mm Square Filter Holder) and therefore will attach to the 100mm adapter rings or 75mm adapter rings (sold separately) as well as hold the Filter Holder. If you are not using the C-PL filter, remove the 86mm adapter ring from the Filter Holder and attach it to the adapter ring you attached to the lens in Step 2. 
4. To attach the Filter Holder to the adapter ring we found that the best way is to locate the two small metal tabs on the inner rim of the holder and insert the adapter ring under these tabs first. Then secure with the locking knob which is located on the opposite corner of the filter holder. Slightly loosen the locking knob if the adapter ring does not drop into place. DO NOT CONTINUALLY TURN THE LOCKING KNOB ANTI-CLOCKWISE AS IT WILL DETACH FROM THE HOLDER and you may lose it. If you lose it, the Filter Holder cannot hold the filters in place.  TIP:  we used a small flathead screwdriver to tighten the locking knob screw. Ideally, this locking knob should not be able to be removed.
5. Once locked in place, ensure it is securely connected before inserting the filters. Initially, we discovered the filters were quite tight in the filter holder. This may loosen over time with some use. We suggest you hold the camera securely when adding the filters or consider adding the filters prior to attaching the filter holder to the camera.
6. To remove the Filter Holder slightly turn the Locking Knob anti-clockwise to release. 

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Conclusion

The URTH Square Filter Holder is a great addition to their product range, however, in our opinion, it still needs some tweaks to be perfect. Firstly, the locking knob on the rear of the holder is not ideal and could easily be lost. We also think that the knob should be a different colour from the holder as it is quite difficult to see. The only other minor improvement is the tightness of the filters in the slots, although as mentioned, this may improve with use. The holder has been designed primarily to be used with the URTH Square ND Filters as they do not have a rubber gasket attached to the rear of the filter and therefore are easier to insert into the first slot. However, if you own existing Square ND Filters from another manufacturer that has a gasket attached to the rear of the filter you will more than likely have to remove the gasket to use in the first slot of the URTH holder. 

All-in-all, it is a sleek, functional and well-designed holder that has been a long time coming and we’re sure that photographers will get a lifetime of use out of the product. We envisage that this product would be perfect for the photographer aiming to purchase their first filter holder. 

Except for the purchase of the individual filters, here’s what you’ll need to order if you want to use the URTH 75mm or 100mm Filter Holder –

1. URTH 100mm or 75mm (now discontinued) Filter Holder
2. URTH Adapter Rings if using lenses with a smaller thread than 67mm (75mm Holder) or 86mm (100mm holder)
3. URTH C-PL Filter (optional)

The adapter rings are available from 37mm – 86mm for the 100mm Filter Holder and 37mm – 67mm for the 75mm Filter Holder.

RATING: RECOMMENDED 

Price

If you are interested in reading any of our other Gobe /Urth product reviews click the links below –

Disclaimer:  This review is totally unbiased. As Professional Photographers we would never recommend the use of any product unless we have used the product ourselves. We always strive to give you our honest opinion in order to help you make the best choice. We did receive the product with compliments of URTH but were not paid for this review. We may also receive commissions on other links in this post.