Vari ND Artifacts? Check the video

I

iflight

Active member
This was shot on my new Panasonic GH2 with a DIY Vari ND (CPL + LPL):

http://vimeo.com/20280284

Lumix 20mm 1.7
f1.7
1/50th shutter
1080 - 24p
iso 160.
Hoya 77mm L-PL on top of a Marumi DHG Super Circular
(The Marumi got top ratings, up right next to B+W)

I read about this option for an inexpensive Vari ND solution that would also provide polarizing effects, thus giving me a Singh Ray Vari ND DUO at 1/3 the cost (i didn't splurge for the warming PL, so i just get basic polarizing in addition to Vari ND, but without the warming...).

This setup cost me about $130, instead of over $350 for the Singh Ray (again though, i don't have the "warming"...). Not having a standard Vari ND filter to compare to, my question is:

1. How much Variable ND filtration am i getting compared to a standard quality Variable ND filter?

2. You can see that as i dial in the filtration, after a certain point dark edges begin t appear where the filtration is no longer done evenly across the filter. Is this same effect experienced with a standard Vari ND filter?

Do these artifacts that begin to appear towards the darkest end of the filtration range represent the limitation of my DIY setup, or is it a standard phenomenon and i am really not supposed to filter to that degree?

Keep in mind, this is a very bright, sunny day, wide open at f1.7, 50th and iso 160. Normal exposure at that ISO is f4.5 + 4000th / sec.

Am I expecting too much from this setup or do the artifacts that appear simply indicate the limitation of the ND abilities, and i just need to back off a bit and stop down to f2.8?

Any info or comments would be appreciated.
thanks.
 
I get it occasionally with my polaroid faderND, its at a random point in the stop range and varies from time to time, usually when I try to darken it to the max. but I don't get this all the time.
 
i own a Fader ND and i don't think i have ever seen that purple fringe when closing down. You do get some fringing that is noticeable in the sky but not an intense colour like that, just darkening. pretty sure i would remember too if it did happen.
 
MR Fanny said:
i own a Fader ND and i don't think i have ever seen that purple fringe when closing down. You do get some fringing that is noticeable in the sky but not an intense colour like that, just darkening. pretty sure i would remember too if it did happen.
Click to expand...

I just looked at mine to see what color it was and it's not a deep color it just looks like it is dark in certain areas.
 
MR Fanny said:
i own a Fader ND and i don't think i have ever seen that purple fringe when closing down. You do get some fringing that is noticeable in the sky but not an intense colour like that, just darkening. pretty sure i would remember too if it did happen.
Click to expand...

after how many stops do you notice this? I am guessing that i get it after 8 or 9 stops of "clean" ND filtration, if not more before i notice the darkening in the corners.
 
You now have $130 less to put toward a Singh Ray. :)

Seriously, you should be able to go all the way to black with your lens wide open without seeing any artifacts using a good Vari-ND. Maybe some of the guys who've successfully done this DIY can give you some pointers.

I paid the bucks for a non-warming Singh Ray (after multiple LCW Fader NDs) because I wanted something that wouldn't soften my image (regardless of focal length) and wouldn't introduce noticeable artifacts. That said, there are those situations where almost anything you put in front of a lens can introduce something that isn't there when shooting without any filter. But I've found that the Singh Ray is about as close as you can get (using a variable ND) to being "neutral" - other than having the intended ND effect, of course.
 
tflak said:
You now have $130 less to put toward a Singh Ray. :)
.
Click to expand...

I hear that, and that's why i went for some quality fliters, but i guess there is something else going on here that I'm not aware of. So basically you are saying that with a quality Vari ND like the Singh Ray, it will dial you in all the way to complete blackness without introducing any change in coloration? or do you have to change the WB as you incread the filtration?
Thanks.
 
tflak said:
You now have $130 less to put toward a Singh Ray. :)

Seriously, you should be able to go all the way to black with your lens wide open without seeing any artifacts using a good Vari-ND. Maybe some of the guys who've successfully done this DIY can give you some pointers.

I paid the bucks for a non-warming Singh Ray (after multiple LCW Fader NDs) because I wanted something that wouldn't soften my image (regardless of focal length) and wouldn't introduce noticeable artifacts. That said, there are those situations where almost anything you put in front of a lens can introduce something that isn't there when shooting without any filter. But I've found that the Singh Ray is about as close as you can get (using a variable ND) to being "neutral" - other than having the intended ND effect, of course.
Click to expand...

Also interesting, from Singh Ray's site: http://singh-ray.com/varinduo.html
NOTE 2: The design of the Vari-N-Duo Filter may introduce irregularities when used with very wide angle lenses, especially on full-frame cameras. Adjust your focal length and reduce the filter density setting until the irregularities disappear.

This sounds exactly like what i'm noticing on my 20mm (even though it's acting as a 40mm on my GH2 due to crop factor...). tflak, do you notice anything similar with your Singh Ray when used on high density?
 
Here's another video: http://vimeo.com/20283513

Using the 50mm FD @ f1.4 the effect is more even, but again, is this coloration normal or is it due to the DIY Vari ND setup? I figured that buying good filters would work well, but you can even see strange coloration in the sky as i dial in more filtration.

Any thoughts on what's going on here?
 
FWIW I have an LCW FaderND MkII and a cheap Polaroid Vari-ND and I've never* seen these artifacts on any of my glass whether it's the 20mm pancake or Canon FD 35/50/85mm.

*when used properly, i.e. not set for max light kill.

A properly working vari-FD shouldn't need to be operated at its maximum filtration. If you find you need to set the filter that high to avoid blowing things out, try stopping your lens aperture down a bit. Then you can set your vari-ND somewhere near its midpoint, where everything looks better.

I want to trust the math that says a couple of high quality filters slapped together = LCW FaderND killer, but I keep reading about guys who build their own DIY Fader-ND and nine times out of ten they complain about issues like this. I'm thankful I didn't let anyone scare me off buying anything but the $300 Singh-Ray or a $150 DIY. The cheap Polaroid, especially, shows how easy this is to do a perfectly fine vari-ND for not a lot of money.
 
*when used properly said:
That's likely the "problem". I'm a complete noob here, so i had it wide open at f1.7 in bright middle-east sun. I thought the idea of the Vari ND's was to be able to keep the lense wide-open, but i guess stopping down to 2.8 or so is what's needed. It's true, this problem only occurs in the MAX range of the filter, so i guess i'm learning that it's a %0-70 reccomended filtration usage and not beyond? if that's the way these things are meant to be used, then i would say i don't have any problems....i just though i should be able to go full-throttle here...

thanks for the info.
Click to expand...
 
Yes, in theory a vari-ND is supposed to let you shoot wide open, but I find in practice sometimes the sun's too bright to let you shoot wide open with a var-ND without having to crank the filter all the way up, which doesn't look so hot.

I agree with dustylens, if you need that much ND filtering to knock the sun down, use a fixed ND filter, not a vari-ND. How many stops it needs to be rated for is between you and your sun.

iflight said:
That's likely the "problem". I'm a complete noob here, so i had it wide open at f1.7 in bright middle-east sun. I thought the idea of the Vari ND's was to be able to keep the lense wide-open, but i guess stopping down to 2.8 or so is what's needed. It's true, this problem only occurs in the MAX range of the filter, so i guess i'm learning that it's a %0-70 reccomended filtration usage and not beyond? if that's the way these things are meant to be used, then i would say i don't have any problems....i just though i should be able to go full-throttle here...

thanks for the info.
Click to expand...
 
iflight said:
after how many stops do you notice this? I am guessing that i get it after 8 or 9 stops of "clean" ND filtration, if not more before i notice the darkening in the corners.
Click to expand...

its noticeable when its almost closed down but it doesn't have the colour shift that yours has which seems to be the issue here. So yes its fairly normal to have that fringing with a FaderND especially on wider lenses but its not normal to get that colour shift.
 
Have been really busy or I would have posted this sooner. Decided to try and back up what I said earlier about the Singh Ray and going to black without seeing any artifacts. So I decided to do a real torture test.

This was done using a GH2, 160 ISO, 1/60 shutter - lens Leica Summilux 25mm f/1.4 -- shooting wide open, turning Singh Ray Vari-ND from Min to Max settings. And, yes, as the shot becomes increasingly underexposed I do see some purple discoloration. However, have to say that I don't think this would be noticeable under normal use or on anything other than something like the snow you see here. Certainly not anything that I would normally be concerned about since I wouldn't be a) underexposing like this or b) turning the ND to this extreme while shooting.

Interested to hear comments.

http://www.vimeo.com/20413644

EDIT: Password = vari
 
Last edited:
tflak said:
Have been really busy or I would have posted this sooner. Decided to try and back up what I said earlier about the Singh Ray and going to black without seeing any artifacts. So I decided to do a real torture test.

This was done using a GH2, 160 ISO, 1/60 shutter - lens Leica Summilux 25mm f/1.4 -- shooting wide open, turning Singh Ray Vari-ND from Min to Max settings. And, yes, as the shot becomes increasingly underexposed I do see some purple discoloration. However, have to say that I don't think this would be noticeable under normal use or on anything other than something like the snow you see here. Certainly not anything that I would normally be concerned about since I wouldn't be a) underexposing like this or b) turning the ND to this extreme while shooting.

Interested to hear comments.

http://www.vimeo.com/20413644
Click to expand...

thanks alot tflak. looking forward to the video...password?
cheers.
 
shaveblog said:
FWIW I have an LCW FaderND MkII and a cheap Polaroid Vari-ND and I've never* seen these artifacts on any of my glass whether it's the 20mm pancake or Canon FD 35/50/85mm.

*when used properly, i.e. not set for max light kill.

A properly working vari-FD shouldn't need to be operated at its maximum filtration. If you find you need to set the filter that high to avoid blowing things out, try stopping your lens aperture down a bit. Then you can set your vari-ND somewhere near its midpoint, where everything looks better.

I want to trust the math that says a couple of high quality filters slapped together = LCW FaderND killer, but I keep reading about guys who build their own DIY Fader-ND and nine times out of ten they complain about issues like this. I'm thankful I didn't let anyone scare me off buying anything but the $300 Singh-Ray or a $150 DIY. The cheap Polaroid, especially, shows how easy this is to do a perfectly fine vari-ND for not a lot of money.
Click to expand...

+1
my FaderND is great
 
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