Review – URTH ND8-128 Variable Filter + Discount Code

UPDATE: As of the 24th November 2020 GOBE has been re-branded as URTH.
Please Note: We have changed all our links to the URTH version of the filters even though we have tested the GOBE branded version.

As mentioned in our previous post “Review – URTH ND2-400 Variable Filter + Discount Code”, we have never really been big fans of using a Variable ND Filter in our photography. Mainly because we’d heard so much about the dreaded ‘X’ Effect issue that these filters have. The URTH ND2-400 filter does have the ‘X’ effect when used at the Maximum Setting and it is usable from 1 stop to about 5 stops reduction in light. Beyond the 5 stops, the corners are just too dark for our liking although some people may find it acceptable. As we needed a second Variable Filter we decided to get the more expensive URTH ND8-128 Variable Filter (USD$99.00 / 77mm thread) which in effect reduces light by 3 stops to 7 stops. Is it worth it? Keep reading to see our conclusion at the end of this post.

So, what is a Variable ND filter?

A Variable ND filter is a neutral density filter that allows you to manually adjust the density (strength) of the filter. Typically, you twist a ring on the outside of the filter, similar to a polarizing filter, and the filter shifts between low and high densities (often anywhere from 1 up to 10 stops of light depending on the brand).

Why use a Variable ND filter?

As Travel Photographers we tend to take a wide range of images and more recently during trips to Japan, Hong Kong, Macau and Shanghai we have been taking a lot of street/urban type images. We love to blur movement in our images, and this was not ideal at times using our bulky NiSi Square Filter Holder combined with the 6 or 10-stop filters, so on bright sunny days, many of our images had to be shot at a small aperture (f16-22) with low ISO settings to obtain the slow shutter speeds that we required. However, shooting at a small aperture can result in ‘Diffraction‘, which most photographers try to avoid (don’t worry about shooting at small apertures if your intended output is just social media). Ideally, we wanted to shoot at larger apertures (f2.8-f8) but with slower shutter speeds (see image below). The only alternative solution was to look at a Variable ND filter where we would have complete control over the amount of light that would allow us to achieve the slow shutter speed we needed.

Please Note: We are NOT dedicated Landscape Photographers. For our tripod-mounted landscape images, we would generally NOT use a Variable ND Filter. Instead, we would use the URTH square ND Filters.

Peak Design Travel Tripod
Tokyo, Japan

Shibuya Crossing, Tokyo – Japan

As mentioned above, Variable ND Filters have had a reputation over the years for being quite expensive. However, over the last couple of years, we have been using the GOBE/URTH brand of filters and have found their filters to be of the highest standard in quality, while still remaining reasonably priced. The URTH ND8-128 Variable Filter ranges in price from USD$67.00 for the 37mm lens thread up to USD$138.00 for the 95mm lens thread (check out the discount coupon code at the end of this post). The filter arrived in a round metal case slightly larger than the filter (so much better than the crappy plastic cases that are supplied by some filter makers). Also included was a URTH Cleaning Cloth which is a great touch. The filter is well-made and the rotating ring is smooth although it is a little tight to rotate which, in our opinion, is a good thing as it restricts it from moving once set. The rotating ring is also quite narrow so for those of you with ‘big fingers’ it may be a bit awkward, however, it is a necessary evil to avoid excessive vignetting in the corners of the frame. The filter is made with premium German B270 Schott optical glass with 20 layers of ultra-nano coating and is weather sealed.

Photography Planner

The Filter

The URTH ND8-128 Variable Filter can be rotated from ND8 (12.5% light transmittance) which is equivalent to 3-stops all the way up to ND128 (0.781% light transmittance) which is equivalent to 7 stops. This is a fantastic range to work with, and will cover most of your needs. The lens has MIN marked on the rim of the filter denoting ND8 (3 f-stops) and the MAX denotes ND128 (7 f-stops). It also has markings on the rim to denote each stop of light reduction.

Vignetting

In our testing with the Gobe version of the filter we were given, we have found that it works well with wide-angle focal ranges such as 16mm-24mm. We tested it with our Sony FE 24-105 f/4 and Sony FE 16-35 f/4 lenses. Straight out of the camera the filter causes vignetting on the 24-105mm lens but this is immediately corrected once the lens profile is applied in post-processing. We used a 77mm-72mm step-up ring to use on the 16-35mm lens which caused some vignetting. Even without the step-down ring, there should be some vignetting, however, we are unable to test whether this is completely correctable on the 16-35mm lens in post-processing.

The ‘X’ Effect

No matter what focal range you use we have found that the dreaded ‘X’ effect issue does not affect images when you use this filter.

Colour Cast

The filter will give you a colour cast. As you can see from the test images below the filter displays a slightly warmer colour cast than the shot without a filter. Personally, we don’t mind this. 

Filter Markings

There are no ‘stop’ markings on the filter so when using the filter you will need to have some sort of an idea of the shutter speed you want to attain for your image. Naturally, at the ND8 setting, it should be a 3-stop (or thereabouts) reduction in light but beyond that, you will have to watch your shutter speed if you want to calculate full-stop increments. Quite frankly, we would suggest you ignore the marks on the filter ring and instead rotate the ring until you obtain your desired shutter speed to capture the effect you want.

Sharpness

As is the case with most, if not all, Variable ND filters there is a slight loss in sharpness when using this filter. As Variable ND filters are constructed from two circular polarising layers of glass that are placed in opposition to each other, a slight loss of sharpness is to be expected.

Note: This is just a guide. You should always test your filter settings as it may change from copy to copy. The test below was taken using a Sony A7R III camera with a  Sony FE 24-105 f/4 lens at the 24mm focal range. These have only had the lens profile applied and have been straightened. Hover over the images for a magnified view.

Test Images

No filter

Above: La Perouse in Sydney, Australia
Sony A7R III + FE 24-105mm f/4 lens + No Filter
24mm – f/8 – 1/80 – ISO 100 –  WB Auto. Profile Correction added and straightened only

Gobe ND8-128 - Ist Mark

Above: Sony A7R III + FE 24-105mm f/4 lens + URTH ND8-128 filter.
Set to the ND8 (3stop) mark on the filter.
24mm – f/8 – 1/4 – ISO 100 –  WB Auto. Profile Correction added and straightened only.

Gobe ND8-128 -2nd Mark

Above: Sony A7R III + FE 24-105mm f/4 lens + URTH ND8-128 filter. Set to the 2nd mark on the filter.
24mm – f/8 – 0.4sec – ISO 100 –  WB Auto. Profile Correction added and straightened only.

Gobe ND8-128 - 3rd Mark

Above: Sony A7R III + FE 24-105mm f/4 lens + URTH ND8-128 filter. Set to the 3rd mark on the filter.
24mm – f/8 – 0.6sec – ISO 100 –  WB Auto. Profile Correction added and straightened only.

Gobe ND8-128 -  4th Mark

Above: Sony A7R III + FE 24-105mm f/4 lens + URTH ND8-128 filter. Set to the 4th mark on the filter.
24mm – f/8 – 1.3sec – ISO 100 –  WB Auto. Profile Correction added and straightened only.

Gobe ND8-128 - Max ND128

Above: Sony A7R III + FE 24-105mm f/4 lens + URTH ND8-128 filter. Set to the ND128 mark on the filter.
24mm – f/8 – 1.6sec – ISO 100 –  WB Auto. Profile Correction added and straightened only.

CONCLUSION

We found this filter easy to use. It gave us so much more control over our shutter speed when shooting at our ideal apertures. The filter is ideal for wide-angle lenses, however, as mentioned we can not vouch for the lens correction performance on lenses wider than 24mm. Undoubtedly there will be some vignetting on wider lenses which should be correctable in-camera or in post-processing, but to what degree, we are not sure.

The filter is available in the following lens thread sizes – 

37 – 40.5 – 43 – 46 – 49 – 52 – 55 – 58 – 62 – 67 – 72 – 77 – 82 – 86 – 95

At the time of writing this post, the filter is priced from AUD$86.00 up to AUD$174.00 based on the lens thread size. To purchase the filter click on the banner below.

This filter is HIGHLY RECOMMENDED

You may also want to consider the URTH Variable ND2-32 Plus+ filter (1-5 stops) 

Other Gobe/Urth Filter Reviews

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

Urth Discount

Disclaimer:  Although we are affiliated with URTH Filters and receive a commission on any sales when using the coupon code, this review is totally unbiased (we are also NiSi Resellers). As Professional Photographers we would never recommend the use of any product unless we use the product ourselves. We did receive the filter with compliments of URTH Filters but were not paid for this review. We may also receive commissions on other links in this post, however, we try our best to keep things fair and balanced, in order to help you make the best choice.