Filter for IR contamination at DVinfo.net

Derek Reich · February 3rd, 2009, 08:47 PM

I have read a lot of posts here and elsewhere regarding the IR contamination with the EX. I have personally experienced the IR contamination several times in a big way.... so to alleviate the problem and be prepared for similar situations in the future.... I am interested in purchasing an IR cut filter to correct the problem when it appears again (in 4X4 for matte box use). But which filter? I have read that the Schneider 750 is the one to buy, then I've read it won't work on an EX. I have read the 486 is going to solve the problem with an EX, then I've read that was developed for digital still cameras, and isn't the best option for video cameras. I haven't heard much about the 'Hot Mirror' filters (I think Tiffen and/or Format) and how successful they may be.

Anyone with any suggestions/experience with any or all of these filters? I'm also concerned about vignetting with some of these filters at wide angle. Any input would be greatly appreciated!

Les Nagy · February 4th, 2009, 11:37 PM

I can tell you that the 750 didn't do anything for my EX3, but the 486 does with some green vignetting that can be at least partially corrected in post. I was talking to one of the engineers at Schneider and he encojraged me to keep in touch with me so I could help with testing solutions, but he has since ignored all attempts at communication.

I hold little hope of anything being done in the near future and have decided on using a 486 as a compromise where the IR problem is too offensive to ignore.

Brian Cassar · February 5th, 2009, 12:48 AM

I too have tried to clear this thing with Schneider and they have instructed me to buy the 486 instead of the Tru-Cut 750 since this does not work with the EX series but was meant to work with the RED camera. I've just received the 486 2 days ago and as soon as I've put it on I immediately saw the green vignetting at the extreme wide setting.

It seems that I have to avoid going to the full extreme wide and any slight cast will have to be corrected in post - a pain yes BUT much better than the aweful ugly contamination that I have encountered with this camera. Any filming of black fabrics under halogen light is a nightmare with this camera.

It seems that there isn't much choice and since the EX series are the only cameras that exhibit such severe contamination, I'm not sure whether companies will bent backwards to find a solution to a problem which apparently is not always problematic to all EX users.

Derek Reich · February 5th, 2009, 08:54 AM

Thanks, Brian, Les-
That's what I had read in both of your previous posts. Interesting that Schneider is now recommending the 486 over the 750? One post I had read by Ryan Avery he was suggesting just the opposite. The problem for me is that I rarely do any of my own editing, my clients take the media and run. So correcting in post is not really an option for me, and not something I want to have to explain to a client who will most likely be less than thrilled about it. A bit of a conundrum, I guess. Has anyone seen the contamination on objects other than fabrics?
Both times I noticed a rather severe amount of contamination happened under daylight conditions. One was outdoors in the Nevada desert just before sunset. The light was of course very low, so it was quite warm (a nice look, I didn't re-balance for the low light) and a woman we were interviewing was wearing a black sweater. The interview continued past sundown, and looking at the clip later, you can actually see the sweater turn from a deep magenta back to black as the sun dipped under the horizon. The producer was understanding (and fortunately that part of the interview wasn't going to be used anyway) but needless to say this is not something you want to have to explain to a client. The other experience was under HMI lighting with ambient daylight as fill coming in from a window. At least that incident remained constant.
This is frustrating, and obviously there does not appear to be a solution? I remember when tight pinstripes were our biggest worry in fashion on camera......

Jay Gladwell · February 5th, 2009, 09:15 AM

Quote:

Originally Posted by Brian Cassar

I've just received the 486 2 days ago and as soon as I've put it on I immediately saw the green vignetting at the extreme wide setting.

It's a shame one has to pay for "green vignetting." I shot a concert under theatrical lighting at a major venue, some of their tuxedoes came out black, while others came out brown (what's that tell you?). I'd rather have that than the green vignette!

Besides, the client didn't bat an eye at the differences in tuxedoes.

Once the folks at Schneider (or elsewhere) are able to offer a clean fix, then I'll invest in the filter.

Derek Reich · February 5th, 2009, 09:22 AM

I agree with you, Jay. I'd rather let people think someone was wearing a different color sweater than deal with the green vignetting. Besides, who's going to know if everything else is correct? Even my lav windsock turned the same color.... it looked like I had a perfectly matched windsock for every occasion!

Derek Reich · February 5th, 2009, 09:23 AM

I agree with you, Jay. I'd rather let people think someone was wearing a different color sweater than deal with the green vignetting. Besides, who's going to know if everything else is correct? Even my lav windsock turned the same color.... it looked like I had a perfectly matched windsock for every occasion!
Maybe one day we'll have an effective solution. I'm certainly not going to drop $200-$400 for a filter which only partially works.

Tim Polster · February 5th, 2009, 10:16 AM

This issue seems like something the companies don't want to talk about as they do not have an answer.

How do you correct for "green vignetting" anyway?

A correction for the outside of the frame would throw the inside off!

Jay Gladwell · February 5th, 2009, 10:27 AM

Quote:

Originally Posted by Tim Polster

How do you correct for "green vignetting" anyway?

My question, Tim, would be what are they doing to get it? I'm not aware of any other filter (still or motion) that causes such an issue, and I've been making images for 40 years.

Giroud Francois · February 5th, 2009, 10:48 AM

if you are not zooming too much with the filter, you can try to get a still from a white wall at full wide. this will give you a mask you can use to correct the default.
this will probably require to convert the green to magenta or orange and use some "multiply" feature in color correction.
Since i got the filter and same problem, i will soon try to find the best way to do that.
if you zoom , you can try to track some point in the video and use it to apply a zoom on the mask too , so the correction follows the zoom. I doubt it would be perfectly ok , but it could help enough to forget it.

Brian Cassar · February 5th, 2009, 12:54 PM

Quote:

Originally Posted by Derek Reich

... I'd rather let people think someone was wearing a different color sweater than deal with the green vignetting...

Not when the person happens to be the groom and the groom knows that he has specifically hired a black outfit....

...and yes that's my question as well: How does one correct the green vignetting? I was thinking of creating a sort of a mask with colour correction for the vignet only. Does this makes sense?

...and by the way Derek, it was Ryan Avery himself who way back in November had told me in an e-mail NOT to buy the 486 as it is not good for the EX cameras and now in January this year he told me NOT to buy the Tru-Cut 750 as this is not good for the EX but that I should buy the 486..!!!!! I have only seen this IR contamination on certain black fabrics - black plastic or metal does not produce such an effect.

I have this gut feeling that no-one will correct this issue - except that future cameras will be produced in such a way to minimise it. In our case we have to lump it.

Simon Wyndham · February 5th, 2009, 05:08 PM

It is disappointing that this issue isn't taken care of much more at source (ie built into the camera).

This issue irritated me on the EX DVD I made. I am in a couple of shots wearing a black jacket and a black fleece underneath, but the fleece is brown. This isn't easily correctable in post because if I bring the fleece closer towards black my jacket will turn bluer.

This is clearly not just an issue with the EX. It affects a lot of other cameras as well. Just a shame that the problem doesn't look like being solved any time soon.

Alex Raskin · February 5th, 2009, 09:20 PM

After a couple of incidents with black fabric turning into ugly brown, I did bite the bullet and bought this 486 filter for EX1.

Hot mirrors I tried did not work; but this filter does very well.

Note that this is a slim version and it fits under the stock lens shade of EX1 easily.

I figured, since this filter works mostly by *reflecting* IR light, I can't put any other optical elements in front of it anyway, so why would I need a front groove.

Also, luckily, I have not run into any perceptible green vignetting yet, so can't attest to that.

Tim Polster · February 5th, 2009, 09:30 PM

Quote:

Originally Posted by Jay Gladwell

My question, Tim, would be what are they doing to get it? I'm not aware of any other filter (still or motion) that causes such an issue, and I've been making images for 40 years.

I don't know as I do not own the camera. I am looking at purchasing one but I shoot a lot of live events and all are lit with the type of lighting that brings out this red colored black issue.

My understanding is that this only happens on the wide end of the lens or if you are using a WA adaptor.

Maybe the light is defracted at a weird angle when the lens is full wide and it escapes the full effect of the filter? Or distorts it?

In the end, between this and the roling shutter the EX-1 does have some compromise built into it. And if one of these compromises happen to be on your job this camera does not hold that much value IMHO.

I talked to Schneider as well and they and Abel Cine are recommending the 486 filter for every EX-1/3.

Sad that Sony does not step up and do something as these are "pro" models.

Alex Raskin · February 5th, 2009, 09:49 PM

Actually Sony does have built-in IR filter, but apparently it is ineffective in certain situations.

I keep my 486 on the lens at all times.

February 3rd, 2009, 08:47 PM	#1
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	Filter for IR contamination I have read a lot of posts here and elsewhere regarding the IR contamination with the EX. I have personally experienced the IR contamination several times in a big way.... so to alleviate the problem and be prepared for similar situations in the future.... I am interested in purchasing an IR cut filter to correct the problem when it appears again (in 4X4 for matte box use). But which filter? I have read that the Schneider 750 is the one to buy, then I've read it won't work on an EX. I have read the 486 is going to solve the problem with an EX, then I've read that was developed for digital still cameras, and isn't the best option for video cameras. I haven't heard much about the 'Hot Mirror' filters (I think Tiffen and/or Format) and how successful they may be. Anyone with any suggestions/experience with any or all of these filters? I'm also concerned about vignetting with some of these filters at wide angle. Any input would be greatly appreciated!

February 4th, 2009, 11:37 PM	#2
Les Nagy Major Player Join Date: May 2006 Location: A Canadian in Canada, and sometimes Chile Posts: 265	I can tell you that the 750 didn't do anything for my EX3, but the 486 does with some green vignetting that can be at least partially corrected in post. I was talking to one of the engineers at Schneider and he encojraged me to keep in touch with me so I could help with testing solutions, but he has since ignored all attempts at communication. I hold little hope of anything being done in the near future and have decided on using a 486 as a compromise where the IR problem is too offensive to ignore.

February 5th, 2009, 12:48 AM	#3
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	I too have tried to clear this thing with Schneider and they have instructed me to buy the 486 instead of the Tru-Cut 750 since this does not work with the EX series but was meant to work with the RED camera. I've just received the 486 2 days ago and as soon as I've put it on I immediately saw the green vignetting at the extreme wide setting. It seems that I have to avoid going to the full extreme wide and any slight cast will have to be corrected in post - a pain yes BUT much better than the aweful ugly contamination that I have encountered with this camera. Any filming of black fabrics under halogen light is a nightmare with this camera. It seems that there isn't much choice and since the EX series are the only cameras that exhibit such severe contamination, I'm not sure whether companies will bent backwards to find a solution to a problem which apparently is not always problematic to all EX users.

February 5th, 2009, 08:54 AM	#4
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	Thanks, Brian, Les- That's what I had read in both of your previous posts. Interesting that Schneider is now recommending the 486 over the 750? One post I had read by Ryan Avery he was suggesting just the opposite. The problem for me is that I rarely do any of my own editing, my clients take the media and run. So correcting in post is not really an option for me, and not something I want to have to explain to a client who will most likely be less than thrilled about it. A bit of a conundrum, I guess. Has anyone seen the contamination on objects other than fabrics? Both times I noticed a rather severe amount of contamination happened under daylight conditions. One was outdoors in the Nevada desert just before sunset. The light was of course very low, so it was quite warm (a nice look, I didn't re-balance for the low light) and a woman we were interviewing was wearing a black sweater. The interview continued past sundown, and looking at the clip later, you can actually see the sweater turn from a deep magenta back to black as the sun dipped under the horizon. The producer was understanding (and fortunately that part of the interview wasn't going to be used anyway) but needless to say this is not something you want to have to explain to a client. The other experience was under HMI lighting with ambient daylight as fill coming in from a window. At least that incident remained constant. This is frustrating, and obviously there does not appear to be a solution? I remember when tight pinstripes were our biggest worry in fashion on camera......

February 5th, 2009, 09:22 AM	#6
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	I agree with you, Jay. I'd rather let people think someone was wearing a different color sweater than deal with the green vignetting. Besides, who's going to know if everything else is correct? Even my lav windsock turned the same color.... it looked like I had a perfectly matched windsock for every occasion!

February 5th, 2009, 09:23 AM	#7
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	I agree with you, Jay. I'd rather let people think someone was wearing a different color sweater than deal with the green vignetting. Besides, who's going to know if everything else is correct? Even my lav windsock turned the same color.... it looked like I had a perfectly matched windsock for every occasion! Maybe one day we'll have an effective solution. I'm certainly not going to drop $200-$400 for a filter which only partially works.

February 5th, 2009, 10:16 AM	#8
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	This issue seems like something the companies don't want to talk about as they do not have an answer. How do you correct for "green vignetting" anyway? A correction for the outside of the frame would throw the inside off!

February 5th, 2009, 10:48 AM	#10
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	if you are not zooming too much with the filter, you can try to get a still from a white wall at full wide. this will give you a mask you can use to correct the default. this will probably require to convert the green to magenta or orange and use some "multiply" feature in color correction. Since i got the filter and same problem, i will soon try to find the best way to do that. if you zoom , you can try to track some point in the video and use it to apply a zoom on the mask too , so the correction follows the zoom. I doubt it would be perfectly ok , but it could help enough to forget it.

February 5th, 2009, 05:08 PM	#12
Simon Wyndham Trustee Join Date: Dec 2003 Location: Malvern UK Posts: 1,931	It is disappointing that this issue isn't taken care of much more at source (ie built into the camera). This issue irritated me on the EX DVD I made. I am in a couple of shots wearing a black jacket and a black fleece underneath, but the fleece is brown. This isn't easily correctable in post because if I bring the fleece closer towards black my jacket will turn bluer. This is clearly not just an issue with the EX. It affects a lot of other cameras as well. Just a shame that the problem doesn't look like being solved any time soon.

February 5th, 2009, 09:20 PM	#13
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	After a couple of incidents with black fabric turning into ugly brown, I did bite the bullet and bought this 486 filter for EX1. Hot mirrors I tried did not work; but this filter does very well. Note that this is a slim version and it fits under the stock lens shade of EX1 easily. I figured, since this filter works mostly by reflecting IR light, I can't put any other optical elements in front of it anyway, so why would I need a front groove. Also, luckily, I have not run into any perceptible green vignetting yet, so can't attest to that.

February 5th, 2009, 09:49 PM	#15
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Actually Sony does have built-in IR filter, but apparently it is ineffective in certain situations. I keep my 486 on the lens at all times.