Filter for IR contamination

Derek Reich · February 5th, 2009, 10:14 PM

Has anybody seen the 486 in a 4X4? The 77mm will be useless with a matte box on. (if you plan on using any filters in the matte box, that is)

Jay Gladwell · February 6th, 2009, 05:53 AM

Quote:

Originally Posted by Tim Polster

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

No, that's not the case. It happens regardless of the focal length and without any adaptors.

Quote:

Originally Posted by Tim Polster

In the end, between this and the roling shutter the EX-1 does have some compromise built into it.

The rolling shutter is an urban legend. It's not the camera, it's the user.

Quote:

Originally Posted by Tim Polster

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

Agreed! Surely they saw this issue in pre-production models!

Brian Cassar · February 6th, 2009, 06:44 AM

Quote:

Originally Posted by Jay Gladwell

No, that's not the case. It happens regardless of the focal length and without any adaptors.

Really?! Ouch..! From the little testing that I did I only saw it in th extreme wide setting of the stock lens. So can it happen even in the telephoto setting?

...and how are you correcting it in post, if I may ask?

Daniel Alexander · February 6th, 2009, 07:34 AM

is the IR contamination only a problem with tungsten/halogen based lighting sources or have their been any other nasty suprises?

Jay Gladwell · February 6th, 2009, 08:11 AM

Quote:

Originally Posted by Brian Cassar

Really?! Ouch..! From the little testing that I did I only saw it in th extreme wide setting of the stock lens. So can it happen even in the telephoto setting?

We're talking about the blacks looking brown, right?

Quote:

Originally Posted by Brian Cassar

...and how are you correcting it in post, if I may ask?

Insofar as correcting in post, I haven't. You can't really. So far I've been lucky. The concert I shot was lit with theatrical lighting, which ranged from white to blue to green to magenta to red--mixed. So the audience presumes it's just the colored lights.

Problem was, as I mentioned, some of the tuxedoes looked brown and some looked black! Also, as someone mentioned, if you try to remove the red cast in the black, you add green or blue to the other areas. So pick your poison!

There may be some very sophisticated (expensive) applications out there that could correct it, but I certainly can't afford them.

Derek Reich · February 6th, 2009, 08:52 AM

Quote:

Originally Posted by Daniel Alexander

is the IR contamination only a problem with tungsten/halogen based lighting sources or have their been any other nasty suprises?

I have seen it both outside under daylight (although it was very warm daylight, just before sunset) and controlled HMI (5600 balanced lighting) with some ambient daylight coming in from windows. I would estimate the sunset light temp would have been around 4400-4500K, and I remember the HMI lighting was about 4600K (realizing that the number the camera gives is rather subjective) but these two values are pretty close. As I described in my earlier post, when the sun dipped below the horizon in the sunset scenario, the IR contamination disappeared before my eyes. That color temp (when the sun was no longer visible) was probably around 7000K. I have not done much incandescent light shooting with this camera, yet, so I can't speak to that.... but I know others have seen the contamination under incandescent light around 3200K.

That said, I just remembered something a Sony tech I spoke with told me, which I haven't tested yet. He asked a very good question when I described my experience with the IR contamination, he asked if I was using a custom picture profile, or the standard one? I hadn't thought of that.... I was on a custom profile. He did not infer that a custom profile was causing the issue, but wondered if adjusted gamma and black might have made the contamination appear worse? I think it's a valid question, at least I will switch to the standard profile next time I have a contamination issue, and just see if anything looks different? Worth a shot, anyway..... which leads to the next thought: I wonder if a PP could be developed specifically for IR contamination? I was using Doug Jensen's PP from the Vortex Media DVD before anyone asks. I'm not saying for a moment that this PP is causing to the problem, but it's valid to see if anything other than the standard set makes a difference. Sony probably never bench tested the cameras in anything other than their vanilla standard setting.
Hey, all you PP developers out there? Here's your chance! Knock yourselves out.....

Tim Polster · February 6th, 2009, 09:23 AM

Quote:

Originally Posted by Jay Gladwell

No, that's not the case. It happens regardless of the focal length and without any adaptors.

The rolling shutter is an urban legend. It's not the camera, it's the user.

Jay, I was speaking to the green cast from the 486 filter which is only supposed to appear when at full wide or using a WA adaptor.

And the rolling shutter effect that bother me is the strobe handling with half exposed frames which is not a myth.

Jay Gladwell · February 6th, 2009, 09:36 AM

Quote:

Originally Posted by Tim Polster

Jay, I was speaking to the green cast from the 486 filter which is only supposed to appear when at full wide or using a WA adaptor.

Okay, sorry! Yes, that is correct.

Quote:

Originally Posted by Tim Polster

And the rolling shutter effect that bother me is the strobe handling with half exposed frames which is not a myth.

From the tests I've seen online from other videographers, it's user error. This would also include my personal experience with the EX3. I've recording people being photographed with a strobe and there were no half exposed frames. What else can I say?

Ned Soltz · February 6th, 2009, 10:40 AM

I've been trying to sort out the IR issue for quite some time.

While endemic to CMOS cameras, IR contamination can even occur with CCD cameras. I shot Steve Job's keynote at MacWorld 2008 (wow, the last Jobs keynote ever) on an HVX200. It really looked great, even down to Steve's brown turtleneck. Yes, IR contamination under tungsten light using CCD's.

I've tested the Schneider 750 but really can't see any difference, mainly because I just have not been able to re-create a contaminated scene.

I've got an email into my contact now at Schneider just to see what they are recommending these days. I have not tested the 486 yet.

Rolling shutter on CMOS cameras is real. The question is the extent to which it affects your shot. If I were shooting strobes in a club, I'd probably shy away from a CMOS camera.

But for what I do (and I confess to being more of a tech type and writer than full-time shooter), the EX cameras produce amazing images.

Brian Cassar · February 6th, 2009, 10:42 AM

Jay, it was my confusion. I was referring to the green vignetting - I thought that you saw the green vignetting at the telephoto setting - that's why I was shocked. But now I realized that you were referring to the IR contamination.

Also I was asking how the green vignetting (and not the IR contamination) can be arranged in post.

And as for Dereck's question, no I always use the original factory settings (no pp's no alteration whatsoever of the picture at all) and yet I saw the abysmal IR contamination on particular fabrics only. I could be shooting in halogen and one piece of black fabric appears black and another black piece of different material appearing nauseatingly brown.

Jay I do not want to side track this thread but what could be the user error in the rolling shutter effect? I film a lot of footage where there are a lot of flashes going off - it's a matter of how the light falls on the subject and ultimately on the sensor. But I've seen loads of half frames and I cannot see what I'm doing wrong. I'm doing the same what I used to do with the CCD cameras - in the CCD cameras I use to get 1 whole frame white washed and now I get half a frame. No big deal really but it's the camera's fault not mine, in my opinion.

Jay Gladwell · February 6th, 2009, 10:56 AM

Brian, I replied via e-mail. Thanks!

Bob Grant · February 6th, 2009, 05:55 PM

We have 3 EX1s in our fleet and 2 EX3s. All are fitted with 486 slim filters. These cameras are used by many people.
Prior to fitting the 486 filters some had noticed the IR contamination problem. Since fitting the filters no one has had that problem and no one has mentioned the green vignetting problem. I've not noticed it myself or if it was there it's not bad enough to need correction to my eyes.

If you do need to correct it, it would be easy enough to correct. Duplicate the track, apply color correction and a circular mask to the upper track. If you're a Vegas user the Cookie Cutter FX with a circular cutout and feathered edge should do the trick.

The rolling shutter issue is not an urban myth. It's is well documented, understood and affects many cameras. What is an urban myth is how much the issue affects most of us. it might be a problem for those few matching CGI elements in post in fast moving scenes. The half flash frames should be very easy to fix if they are a visual nuisance but the odd one or two I've noticed I just left.

If you're looking for a reason not to buy any camera you can always find one or two :)
Neither of these are good reasons in my opinion.

Tim Polster · February 6th, 2009, 10:18 PM

Good to know about the filters Bob.

Jay Gladwell · February 7th, 2009, 08:00 AM

IF the rolling shutter was ever more than anecdotal, and that's a BIG if, it isn't now. The one thing I will agree with Bob on is if you're looking for a reason not to buy any camera...

The IR contamination goes further than being anecdotal. However, taking everything else into consideration, not the least of which is the image quailty, it's well worth that small inconvenience, in my opinion.

Alex Raskin · February 7th, 2009, 08:27 AM

Ignoring shortcomings of the particular camera seems like disservice to people who are trying to learn about strong points as well as weaknesses of the device.

IR contamination: certain black surfaces turn brown under *any* lighting conditions - I've seen it under the natural sunlight; tungsten; fluos...

Rolling shutter: what is this discussion about? Of course there is rolling shutter issue with EX1. It manifests itself in skewed vertical lines on very fast pans; as well as in the fact that photo flashes are exposed only partially in the frame. Go frame-by-frame in your NLE to see for yourself. If you can't see it, you are not looking close enough.

Now, does it matter for the average viewer?

Blacks turning into brown - yes it matters. That's why I always have my slim 486 filter on my EX1.

Rolling shutter issues - not so much. Fast pans are blurred anyway, so it's hard for the viewer to discern the skewed lines at normal playback speed. Same with flashes; hard to see that one frame is only partially exposed at normal projection speeds...

February 5th, 2009, 10:14 PM	#16
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	Has anybody seen the 486 in a 4X4? The 77mm will be useless with a matte box on. (if you plan on using any filters in the matte box, that is)

February 6th, 2009, 07:34 AM	#19
Daniel Alexander Major Player Join Date: Jul 2007 Location: West Midlands, UK Posts: 320	is the IR contamination only a problem with tungsten/halogen based lighting sources or have their been any other nasty suprises?

February 6th, 2009, 10:40 AM	#24
Ned Soltz Major Player Join Date: May 2006 Location: Teaneck, NJ Posts: 659	I've been trying to sort out the IR issue for quite some time. While endemic to CMOS cameras, IR contamination can even occur with CCD cameras. I shot Steve Job's keynote at MacWorld 2008 (wow, the last Jobs keynote ever) on an HVX200. It really looked great, even down to Steve's brown turtleneck. Yes, IR contamination under tungsten light using CCD's. I've tested the Schneider 750 but really can't see any difference, mainly because I just have not been able to re-create a contaminated scene. I've got an email into my contact now at Schneider just to see what they are recommending these days. I have not tested the 486 yet. Rolling shutter on CMOS cameras is real. The question is the extent to which it affects your shot. If I were shooting strobes in a club, I'd probably shy away from a CMOS camera. But for what I do (and I confess to being more of a tech type and writer than full-time shooter), the EX cameras produce amazing images.

February 6th, 2009, 10:42 AM	#25
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Jay, it was my confusion. I was referring to the green vignetting - I thought that you saw the green vignetting at the telephoto setting - that's why I was shocked. But now I realized that you were referring to the IR contamination. Also I was asking how the green vignetting (and not the IR contamination) can be arranged in post. And as for Dereck's question, no I always use the original factory settings (no pp's no alteration whatsoever of the picture at all) and yet I saw the abysmal IR contamination on particular fabrics only. I could be shooting in halogen and one piece of black fabric appears black and another black piece of different material appearing nauseatingly brown. Jay I do not want to side track this thread but what could be the user error in the rolling shutter effect? I film a lot of footage where there are a lot of flashes going off - it's a matter of how the light falls on the subject and ultimately on the sensor. But I've seen loads of half frames and I cannot see what I'm doing wrong. I'm doing the same what I used to do with the CCD cameras - in the CCD cameras I use to get 1 whole frame white washed and now I get half a frame. No big deal really but it's the camera's fault not mine, in my opinion.

February 6th, 2009, 10:56 AM	#26
Jay Gladwell Join Date: Jul 2002 Posts: 1,244	Brian, I replied via e-mail. Thanks!

February 6th, 2009, 05:55 PM	#27
Bob Grant Trustee Join Date: Nov 2005 Location: Sydney Australia Posts: 1,570	We have 3 EX1s in our fleet and 2 EX3s. All are fitted with 486 slim filters. These cameras are used by many people. Prior to fitting the 486 filters some had noticed the IR contamination problem. Since fitting the filters no one has had that problem and no one has mentioned the green vignetting problem. I've not noticed it myself or if it was there it's not bad enough to need correction to my eyes. If you do need to correct it, it would be easy enough to correct. Duplicate the track, apply color correction and a circular mask to the upper track. If you're a Vegas user the Cookie Cutter FX with a circular cutout and feathered edge should do the trick. The rolling shutter issue is not an urban myth. It's is well documented, understood and affects many cameras. What is an urban myth is how much the issue affects most of us. it might be a problem for those few matching CGI elements in post in fast moving scenes. The half flash frames should be very easy to fix if they are a visual nuisance but the odd one or two I've noticed I just left. If you're looking for a reason not to buy any camera you can always find one or two :) Neither of these are good reasons in my opinion.

February 6th, 2009, 10:18 PM	#28
Tim Polster Inner Circle Join Date: Dec 2004 Location: Arlington, TX Posts: 2,231	Good to know about the filters Bob.

February 7th, 2009, 08:00 AM	#29
Jay Gladwell Join Date: Jul 2002 Posts: 1,244	IF the rolling shutter was ever more than anecdotal, and that's a BIG if, it isn't now. The one thing I will agree with Bob on is if you're looking for a reason not to buy any camera... The IR contamination goes further than being anecdotal. However, taking everything else into consideration, not the least of which is the image quailty, it's well worth that small inconvenience, in my opinion.

February 7th, 2009, 08:27 AM	#30
Alex Raskin Trustee Join Date: Sep 2003 Posts: 1,435	Ignoring shortcomings of the particular camera seems like disservice to people who are trying to learn about strong points as well as weaknesses of the device. IR contamination: certain black surfaces turn brown under any lighting conditions - I've seen it under the natural sunlight; tungsten; fluos... Rolling shutter: what is this discussion about? Of course there is rolling shutter issue with EX1. It manifests itself in skewed vertical lines on very fast pans; as well as in the fact that photo flashes are exposed only partially in the frame. Go frame-by-frame in your NLE to see for yourself. If you can't see it, you are not looking close enough. Now, does it matter for the average viewer? Blacks turning into brown - yes it matters. That's why I always have my slim 486 filter on my EX1. Rolling shutter issues - not so much. Fast pans are blurred anyway, so it's hard for the viewer to discern the skewed lines at normal playback speed. Same with flashes; hard to see that one frame is only partially exposed at normal projection speeds...