Lee Filters - ND Grad Image Distortion - Garry Ridsdale Commercial Photography

Lee Filters - Check New Filters ASAP

Following the release of a new range of filters from Lee I purchased a 0.9ND Medium Grad to complement the existing range of filters I owned.  (1/2/3 stop ND Soft - 2&3 stop ND Hard - Big Stopper and a 1.2 ND).  I've used these filters extensively for many years and they've each served me well wherever they've been used.

It was therefore an unwelcome surprise to see degraded images when the filter was in place, particularly distorted around where the gradation began.

The images (below) were taken on a Canon 5DsR and a Canon 70-200 f/2.8 L IS USM II at 110mm, 1/20 sec, f/8, ISO 100, manual focus, Image Stabilisation Off.  Mounted on an Arca Swiss D4 geared head on a Gitzo 5541LS tripod.  There was no wind to affect the image.  All of the images are straight jpg conversions of the raw file - no editing has been done and only default settings left from Lightroom.

With New 0.9 ND Medium Grad

Image with 0.9 Medium ND

Cropped Close Up of Distortion

Image with 0.9 Medium ND

Taken with 0.9ND Soft Grad

Not Shot with 0.9 Medium

Cropped - Showing No distortion

Not Shot with 0.9 Medium

It was clear that the filter was causing some distortion and it seemed to be occurring just where the gradation began.  Even when using Live View the effects of the filter distorting the image could be seen as it was moved down the holder in-front of the lens.

For completeness, I took a series of images with other Lee filters all at the same settings and none exhibited any sort of image degradation.

Validating the Results


The following morning I set up a test area at home using a lens test chart that I use to check my lenses for focus accuracy and sharpness/diffraction.

My 5DsR and 70-200 were once again used - mounted on the Arca geared head and Gitzo tripod.  Setting were 100mm - 1/50 sec f/8 ISO 100 - manual focus, IS off.

With 0.9ND Medium Grad

with 0.9 nd medium gradation placed at top of test chart

The effects of the Grad can clearly be seen with the gradation beginning around the centre, rising to the top.  The image below shows a crop and the distortion that is evident around the central section of the test chart.

Crop Close Up With 0.9 ND Medium

with 0.9 nd medium gradation placed at top of test chart

To show that there were no issues with either the camera or lens the images were taken again but without the filter.  As can be seen there are no focus / distortion issues.

With No Filter Attached

Crop with No Filter

I repeated the test with other Lee filters and like I had experienced in the field earlier there were no distortion issues.


Conclusions

It's obviously frustrating and time consuming to be testing filters for QC issues particularly from such a reputable manufacturer as Lee. Fortunately, I was only testing the filter on a landscape location close to home in my own time and not on a paid commission. However, if I had been on a commission I would not have had the time to check every image for defects such as distortion - I know the limitations of my cameras and lenses and work accordingly.  I expect filters to work perfectly, especially when they are both expensive and marketed as being hand made.  

With the growth in digital photography and the subsequent increased demand for accessories such as filters have QC standards slipped?  Until recently I've been an admirer of Lee's products (notwithstanding the poor marketing) they've served me very well and help me retain an objective of getting it right in camera rather than relying on post production wizardry.  However, as a professional photographer I need products I can rely on and while I'll continue to use the Lee filters I own (and work) I'd strongly encourage anyone to thoroughly test their filters before they are to be relied upon - perhaps I was just unlucky but nobody wants to be in-front of an epic landscape, or working for a paying client, and find the resultant images are degraded.  Proceed with care.

I hope to receive an explanation from Lee as to the cause of the degradation - my own findings suggest some sort of issue where the clear part of the filter meets the gradation, perhaps a problem with the coating or resin, or perhaps it isn't perfectly flat?  It may also be that longer focal lengths emphasise the problem and that with wide angle lenses it isn't as evident (if at all).  I'll update this post with any finding.


Garry Ridsdale

Aug.2016

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