Every now and again I get a distinct green line or colour cast in the lower third of my photos. This can (but seldom) happen when I’m shooting wide (say 16-20mm), using my Lee 3 stop grad soft GND (100mm x 150mm) with the shot angled away (say 40-70°) from the rising sun.
Other factors in play are I think dark-ish, dawn shots. A small tilt down of the camera so the horizon is higher in the frame. The GND is pushed up in the holder to align the transition line to the horizon. This said, it appears to me that the green hue or line comes from the clear section of the GND.
Here’s an example from yesterday at dawn, 30 minutes before sunrise (on the RHS).
5Ds + 16-35mm f4 L at 16mm.
10, 25s, ISO 400.
The green line can be seen in line with the bottom of the kayak. This would be maybe 25% up from the bottom of the filter, well into the clear section of it.
From the same shoot I have say 60 images, 3 of which have this line. All are wide, taken at dawn and a similar aspect to the attached. The other say 57 are wide too, use the same filter, have a tilt, angled away L & R from the rising sun or straight into the rising sun. But no green line.
Could the age of the filter be in question? Purchased 2011.
Mark, I can’t say I’ve ever had this show up on any images using ND filters, but the caveat is I shoot only film. Do you recall if this is the extreme bottom edge of the filter. Maybe its a bit of CA - chromatic aberration. It usually shows up on film as magenta, cyan, or greenish. If you use any anti-CA software plugins you might try it to see what happens to the green line. It is very faint and with some work can be cleaned up manually I would think.
Perhaps its not the filter at all but a combo of the camera and lens at low light, long exposure and the angle of light entering the lens.
The NPN article on CA suggests closing the aperture (I shoot f11 99% of the time) to increase the DoF. But of course doing this means a longer exposure time so maybe not.
That is a bit more complexing. I thought it was the very edge of the filter bottom. I assume you’re not using any chemicals to clean the filter like Windex. But even that straight of a line would have been on the extreme edge of the filter and not 25% up and that perfectly straight.
Shooting digital at least your not getting any scanning artifacts we film shooters see at times.
Let us know if you find out the culprit. Good luck.
At first I thought the green area followed the curvature of the lens, but on enlargement, it seems to curve up from left to right but then down on the right side toward the water. I also see a vertical line up the far right side upon enlarging the image. If you have access to another GND it might be helpful to take a some shots with it followed by some with the potentially flawed one. Other than that I have no idea what is causing it. Might be time for a new filter.
For some time now I’ve had an issue where a green band appears in some of my landscapes. After a lot of thinking and investigation I think I have diagnosed the cause but I’d really appreciate it if you would read the following and pick holes in my logic, or agree.
This green band will only appear (but not always) when I’m using my 5Ds as follows:
• EF 16-35mm f4 L @ < 24mm
• Low light…usually sunrise/sunset.
• Lee 1.2ND (4 stop) 100mm resin filter is use.
• Landscape orientation, never portrait.
• Always 33% up from the bottom of the frame.
Consider these two examples from the same recent morning shoot. Note that the time stamp is 2 hours behind as the camera was set at AEST and NZ was 2 hours ahead on that day.
In the image “Lake Moke 489” the line first appears and then features in most shots (< 24mm and landscape orientation)following that. If you look closely there’s actually a 2nd fainter line above the first.
I don’t make field notes of when or what filter I have fitted so I surmise that the slower shutter speed in 489 implies that I fitted the 6 stop ND filter in the 90s between these shots. 0.5 to 30 is ~ 5 stops + 1 stop for the exp comp?
The Lee filter is 100mm square and so can be fitted into the holder in any orientation, and back to front which you’d think would make the green band very inconsistent shot to shot, but once fitted I seldom change it for a given shoot.
I think the issue is the 13yo, Lee resin ND filter, not that I can see any physical issues with it. I look after my gear and the filter looks pristine to me. Also, I don’t expect to see a fault with it as there are 8 orientations (4 orientations + flipping it) I could use to fit it on a given shoot.
To my mind the above points to the filter but I’m still not sure.
I have a 3yo Nisi 10 stop and a 14yo Lee 3 stop soft GND. Never an issue.
I think testing is in order. I would try photographing a flat smooth panel, way out of focus, and expose to create a sky-like tone, and compare 3 images, 2 made with the filter at 90 degrees to the other exposure, plus one without the filter. Photoshop ought to be able to detect a color cast with the color picker tool and the color picker properties panel if it is hard to see. I purchased “Breakthrough Photography” branded filters because Sean Bagshaw used them and they were advertised as more color-neutral than all the others, but nowadays I see that magnetic mounts are popular for circular filters, and I don’t use graduated filters as my landscapes don’t really have straight line horizons.
That said, I’ve always thought that green is normally a part of some atmospheres, especially during stormy weather, but sometimes the sky reflects the color of distant terrains, which I notice in desert or maritime landscapes. And, color is now controllable in Photoshop with enough skill. So, it might be the filter, might not, and it might not matter if you can post process till it doesn’t bother you.
In the interim I was pointed to this article where Lee Filters said the resin filters were good for 7 to 10 years. Mine is 13 and would have been 5yo at the time of the article. As such I’ve purchased a new Nisi 6 stop and once got I’ll do a comparison of the two.
Very interesting, especially since I didn’t know how Lee filters are made! A small set of yellow, red, green, and orange Tiffen filters were an important addition to my Argus A2 when I first started photographing. I do recall that the thin gel filters are better for fine resolution than thicker filters, but also did not know that lighting gels were not good for lens filters. It remarkable how much modern filter use is different than the film days, given the ability to “filter” any digital image in software, instead of trying to get close to the right “filtration” at image capture. I only use polarizers and NDs on lenses for extending exposure time if needed anymore, relying on pixel-level masking and merging different exposures in Photoshop to avoid dark and light halos, which never show up when using lens filters at capture.
Well I can throw all of those Lee theories in the bin!
Just back from a few days away doing seascapes. Most of my low light, wide exposures show these bands to some degree and I’d left the Lee resin filters at home!
Apologies to Lee Filters…
So now its got to be the 5Ds or the 16-35 f4 L. Purchased new together in 2019.
I sent both to Canon for assessment and repair but their response did not specifically address the issue; instead they just quoted to replace the shutter mech and Cmos for AUD$2,200 on a camera I paid AUD$3,000 in 2019. The economics of that don’t work for me as I can buy an R5 for AUD$4,000 inc an EF adaptor ring.
So after a lot more research and then some testing I proved it was the camera and not lenses or filters. Set up in a darkened room, 16mm, f11, 30s, ISO100 I can repeatedly get two green bands to appear across the lower half of the image. Its not obvious when played back on the camera’s LCD but in PS with the exposure pushed up 2 stops the bands are bright as day.
So back to researching and I stumbled across some old threads (astro photography) on DP Review that discuss this phenomena as well as hot pixels, with the “fix” being to “remap” the cmos by doing a manual clean with the lens cap on and EVF covered.
Did this and no more green bands! :):)
I’d be happier to find something official on this “remap” thing from Canon but thus far, nothing found.
