Filter for IR contamination

Jay Gladwell · February 7th, 2009, 09:23 AM

Alex, can you name any camera that is 100% perfect--no short-comings whatsoever?

I've not seen any rolling shutter in the EX3--ever--the same is true for many, many others, even with the EX1. The IR issue is, evidently, correctable, so what's the problem?

I stand by assertion that the rolling shutter is a user induced problem. If it weren't, all the EX cameras would be exhibiting it, just like the IR issue.

Ralph Keyser · February 18th, 2009, 11:05 AM

Quote:

Originally Posted by Jay Gladwell

I stand by assertion that the rolling shutter is a user induced problem. If it weren't, all the EX cameras would be exhibiting it, just like the IR issue.

All EX cameras DO exhibit the rolling shutter phenomenon. Along with the RED One, Nikon's D90, and many other CMOS cameras. It's more obvious on some models than others, of course, and on the EX cameras it doesn't seem to be very severe. As mentioned before, most of the time when it would occur, there is enough motion blur that the effect is not objectionable to the eye. I've certainly seen it, but it's one of those things that you really have to be looking for to notice. The EX series cameras do not have bad problems with rolling shutter issues, so I would agree that it's not something to worry about.

Simon Wyndham · February 18th, 2009, 11:14 AM

Apparently the EX does have some rolling shutter compensation built in, but it can't get rid of all issues. Although I have to say that in all my shooting, including fast moving rally cars etc, I have never really noticed it. I've also done a lot of work at full telephoto and not noticed any issues.

Brian Cassar · February 18th, 2009, 12:15 PM

Has anybody tried using this filter on the EX1 or EX3? -

77MM STANDARD HOT MIRROR - Tiffen.Com

If so does it manages to cut the IR? Does it produce any green vignetting? And above all does the lens hood manages to attach to the filter (even though it is not of the slim type)?

Robert St-Onge · February 18th, 2009, 07:03 PM

Quote:

Originally Posted by Brian Cassar

Has anybody tried using this filter on the EX1 or EX3? -

77MM STANDARD HOT MIRROR - Tiffen.Com

If so does it manages to cut the IR? Does it produce any green vignetting? And above all does the lens hood manages to attach to the filter (even though it is not of the slim type)?

Brian, I had purchased the Tiffen 77mm hot mirror filter about 6 months ago and it is totally useless on the EX1. I returned it for a refund. The Schneider 486 is the best option so far. I have a standard 77mm 486 and a 52mm 486 for my Nikon lenses which I use on my Letus.

Derek Reich · February 18th, 2009, 07:13 PM

So I was just preparing for a shoot today, and had my camera on my bench with some stuff laying about. I noticed an old Tiffen filer pouch (which is black) was exhibiting some IR contamination so I played around a bit. I was interested in seeing if changing the profiles made a difference, as a Sony tech once suggested to me.

Here's what I found. First of all, going to the 'standard' (no adjustment) profile made no difference at all. So there's that. But I did notice that one profile I had entered, the recently released 'BBC Film' profile minimized the effects of the contamination somewhat, or at least it seems to. There is probably several reasons for this, but the main thing I notice between the profiles is the different matrix setting. One profile, which is Doug Jensen's which I like very much and use as my regular setting, uses 'HI SAT'. This is the brighter and more saturated of the two images. The other is the BBC profile, which uses the 'CINEMA' matrix setting.

I'm open to suggestions as to why the IR seems much less obvious between the two settings? Maybe there is a chance that changing matrix settings will help when the issue arises? Thoughts, anyone? Also interesting to note that the smooth black of the Chrosziel adapter ring is uncontaminated, as is the border of the old filter pouch.

Jay Gladwell · February 19th, 2009, 07:06 AM

Quote:

Originally Posted by Derek Reich

Also interesting to note that the smooth black of the Chrosziel adapter ring is uncontaminated, as is the border of the old filter pouch.

Yes, we've noticed that on a number of occasions. It seems that this is the result of a variation of fabric and/or dyes.

Bill Ravens · February 19th, 2009, 07:16 AM

I've had a fair amount of experience with infrared(IR) sensing equipment. What appears "black" to the human eye is anything but black in IR wavelengths. You, simply, cannot judge the "color" of an object in the infrared regime with your eyes. It is the black anodizing on the chroziel that exhibits the "un-contamination". I don't know who coined that term, but, I find it rather laughable. Contamination, indeed!

All objects reflect light, to one extent or another. If one thinks in terms of the three primaries, RG and B, objects will reflect each color in different strengths, absorbing some frequencies more than others. Infrared is not a single "color", per se, but a range of colors, or wavelengths. THe CMOS in the EX1 responds differently to different wavelengths, as well, resulting in the uneven interpretation of RGB channels, displaying red more than other wavelengths. No single filter is going to account for the unique infrared signature of all objects that appear black to the human eye. Filter design uses specific coatings to either absorb or reflect certain wavelengths. No single filter will block all the frequencies that are in the IR range. Furthermore, attenuation of undesireable wavelengths is not a step-function, but, rather, a gradient of attenuation as the frequency moves into the IR regime.

Brian Cassar · February 19th, 2009, 09:47 AM

Robert thanks for the info re:Tiffen. I found another possible candidate : Rosco US : Film/Video : Trucolor

The problem is that they do not do them in 77mm circular format. I've contacted the company and they did tell me that they are aware of the green vignetting of certain filters and that theirs do not exhibit such green cast. They didn't mention however whether they have tested it on the EX series. They even went further in offering to cut a 77mm sized filter for me but that it was up to me to mount in on a 77mm thread. (I have no idea how to do it!!)

If someone can confirm that they have used such a filter and that it works with the EX then I will consider buying a hood + filter holder (I'm not interested in matte boxes as they are too cumbersome for my run n gun work that I do).

Anybody bought the Rosco?

Jay Gladwell · February 19th, 2009, 10:15 AM

Great information, Brian. One would think (hope) that if Rosco has "solved" the problem, surely Schnieder couldn't be too far behind.

Brian Cassar · February 19th, 2009, 12:50 PM

Jay, to be fair, Schneider did solve the IR contamination problem with their Tru-Cut 750 but for the RED camera only as it was found out that this filter does not work for the EX cameras. Rosco are saying that their filter works well with no green cast but I suspect that they have been tested for the RED camera as well.

The problem as I see it is that the EX series are so sensitive to IR that an aggressive filter like the 486 will cause a green tint and anything less in IR blocking power will lead to no effect just like the Tru-Cut 750.

I fear that this problem will never be solved for the EX......

Kevin Cates · February 19th, 2009, 03:27 PM

I found a used Tiffen 77mm Hot Mirror ($50) at B & H. I shot with Vortex PP, fairly low ambient tungsten light, 2.8 iris, and found 8 black materials to test. I found the filter cuts the 'brown/magenta' shift a little - but not a lot (see photo). I did not see any 'green cast' on wide or any other focal legnth.

The neoprene wet suit, cotton shirt, and black fleece materials had the hardest time with the CMOS IR.

The camera makes awesome pictures for what it is. For me I don't see an everyday need for an IR cut, so I am keeping this filter to use if it ever becomes an issue. It appears to offer enough of a 'acceptable' correction for any situation I have come across so far. For any critical 'black has to be black' shoots I will probably rent a 486 or use another camera.

Hopefully, a better solution will come.

(Couldn't get an image bigger that 500k to upload on this site)

Ryan Avery · February 19th, 2009, 04:14 PM

Let me set the record straight as it stands right now:

At the beginning of this whole EX and IR light contamination issue we here at Schneider spent some time considering all the options. We made the recommendation of the 486 based on the testing data that we had from real end users and information of the sensor as well as our filter.

We hence discovered some users found that it caused a blue to green cast in their images. I concluded that in certain situations this did not work thus I recommended the True-Cut 750. The True-Cut 750 was shown to work in some but not all situations on the Sony EX cameras only. The RED camera continues to work fine and IR problems are greatly diminished with the True-Cut 750.

So we have discovered that the IR contamination issue with the Sony EX series cameras is dodgy at best and the IR cut required is all over the map given the IR content of the light and the material you are shooting. I have satisfied users on both sides of the fence that use both the True-Cut 750 and the 486 for their EX cameras. Any statements made either way by myself on the use of IR filters were based on the latest info at the time of the post. The IR contamination issue is a developing and quite frankly "moving target" given the camera that is being used and the other variables listed before.

We continue to work on this problem to find a one size fits all solution. Currently, the 486 has the least incidence of issues with end users and continues to be the most popular choice for diminishing the IR issue. But it is not perfect for this particular camera and some users have experienced the blue to green cast whereas others have had no issue.

The best suggestion is to use the 486 for your Sony EX camera if you are desperate for a solution now but realize that there are some risks in using this filter. I am hopeful that we will devise a "perfect" solution but much more testing is required.

I must make it abundently clear that the True-Cut IR 750 is the best solution for the RED camera and any RED user should buy that filter for their camera if using heavy ND filters. The application of the True-Cut IR 750 is only less than ideal for Sony EX users (but does work in some shooting conditions!).

Your patience is appreciated and we are likely to have a workable solution soon.

Ryan Avery
Schneider Optics

Dean Harrington · February 19th, 2009, 05:47 PM

I know that you are working on a solution and shall wait !

Leonard Levy · February 20th, 2009, 01:41 AM

Kevin,

Thanks for posting those pics. Doesn't seem to do much though. I'm figuring I may get something like a 486 eventually. If it works OK except on wide lenses then it would at least be valuable in the event of an interview with a big exec wearing a black jacket. That's a place I could imagine the client getting touchy. No need for a wide there.

Lenny

February 18th, 2009, 07:13 PM	#36
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	for what it's worth.... So I was just preparing for a shoot today, and had my camera on my bench with some stuff laying about. I noticed an old Tiffen filer pouch (which is black) was exhibiting some IR contamination so I played around a bit. I was interested in seeing if changing the profiles made a difference, as a Sony tech once suggested to me. Here's what I found. First of all, going to the 'standard' (no adjustment) profile made no difference at all. So there's that. But I did notice that one profile I had entered, the recently released 'BBC Film' profile minimized the effects of the contamination somewhat, or at least it seems to. There is probably several reasons for this, but the main thing I notice between the profiles is the different matrix setting. One profile, which is Doug Jensen's which I like very much and use as my regular setting, uses 'HI SAT'. This is the brighter and more saturated of the two images. The other is the BBC profile, which uses the 'CINEMA' matrix setting. I'm open to suggestions as to why the IR seems much less obvious between the two settings? Maybe there is a chance that changing matrix settings will help when the issue arises? Thoughts, anyone? Also interesting to note that the smooth black of the Chrosziel adapter ring is uncontaminated, as is the border of the old filter pouch. Attached Thumbnails __________________ www.zooprax.com

February 19th, 2009, 03:27 PM	#42
Kevin Cates Regular Crew Join Date: Sep 2006 Location: Fairfax, CA USA Posts: 33	Tiffen 77mm Hot Mirror test I found a used Tiffen 77mm Hot Mirror ($50) at B & H. I shot with Vortex PP, fairly low ambient tungsten light, 2.8 iris, and found 8 black materials to test. I found the filter cuts the 'brown/magenta' shift a little - but not a lot (see photo). I did not see any 'green cast' on wide or any other focal legnth. The neoprene wet suit, cotton shirt, and black fleece materials had the hardest time with the CMOS IR. The camera makes awesome pictures for what it is. For me I don't see an everyday need for an IR cut, so I am keeping this filter to use if it ever becomes an issue. It appears to offer enough of a 'acceptable' correction for any situation I have come across so far. For any critical 'black has to be black' shoots I will probably rent a 486 or use another camera. Hopefully, a better solution will come. (Couldn't get an image bigger that 500k to upload on this site) Attached Thumbnails

February 19th, 2009, 04:14 PM	#43
Ryan Avery Sponsor: Schneider Optics Join Date: Aug 2007 Location: Van Nuys, CA Posts: 387	EX Cameras and IR Let me set the record straight as it stands right now: At the beginning of this whole EX and IR light contamination issue we here at Schneider spent some time considering all the options. We made the recommendation of the 486 based on the testing data that we had from real end users and information of the sensor as well as our filter. We hence discovered some users found that it caused a blue to green cast in their images. I concluded that in certain situations this did not work thus I recommended the True-Cut 750. The True-Cut 750 was shown to work in some but not all situations on the Sony EX cameras only. The RED camera continues to work fine and IR problems are greatly diminished with the True-Cut 750. So we have discovered that the IR contamination issue with the Sony EX series cameras is dodgy at best and the IR cut required is all over the map given the IR content of the light and the material you are shooting. I have satisfied users on both sides of the fence that use both the True-Cut 750 and the 486 for their EX cameras. Any statements made either way by myself on the use of IR filters were based on the latest info at the time of the post. The IR contamination issue is a developing and quite frankly "moving target" given the camera that is being used and the other variables listed before. We continue to work on this problem to find a one size fits all solution. Currently, the 486 has the least incidence of issues with end users and continues to be the most popular choice for diminishing the IR issue. But it is not perfect for this particular camera and some users have experienced the blue to green cast whereas others have had no issue. The best suggestion is to use the 486 for your Sony EX camera if you are desperate for a solution now but realize that there are some risks in using this filter. I am hopeful that we will devise a "perfect" solution but much more testing is required. I must make it abundently clear that the True-Cut IR 750 is the best solution for the RED camera and any RED user should buy that filter for their camera if using heavy ND filters. The application of the True-Cut IR 750 is only less than ideal for Sony EX users (but does work in some shooting conditions!). Your patience is appreciated and we are likely to have a workable solution soon. Ryan Avery Schneider Optics

February 19th, 2009, 05:47 PM	#44
Dean Harrington Major Player Join Date: Nov 2002 Location: Tokyo Posts: 898	Thanks Ryan ... I know that you are working on a solution and shall wait !

February 7th, 2009, 09:23 AM	#31
Jay Gladwell Join Date: Jul 2002 Posts: 1,244	Alex, can you name any camera that is 100% perfect--no short-comings whatsoever? I've not seen any rolling shutter in the EX3--ever--the same is true for many, many others, even with the EX1. The IR issue is, evidently, correctable, so what's the problem? I stand by assertion that the rolling shutter is a user induced problem. If it weren't, all the EX cameras would be exhibiting it, just like the IR issue.

February 18th, 2009, 11:14 AM	#33
Simon Wyndham Trustee Join Date: Dec 2003 Location: Malvern UK Posts: 1,931	Apparently the EX does have some rolling shutter compensation built in, but it can't get rid of all issues. Although I have to say that in all my shooting, including fast moving rally cars etc, I have never really noticed it. I've also done a lot of work at full telephoto and not noticed any issues.

February 18th, 2009, 12:15 PM	#34
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Has anybody tried using this filter on the EX1 or EX3? - 77MM STANDARD HOT MIRROR - Tiffen.Com If so does it manages to cut the IR? Does it produce any green vignetting? And above all does the lens hood manages to attach to the filter (even though it is not of the slim type)?

February 19th, 2009, 07:16 AM	#38
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	I've had a fair amount of experience with infrared(IR) sensing equipment. What appears "black" to the human eye is anything but black in IR wavelengths. You, simply, cannot judge the "color" of an object in the infrared regime with your eyes. It is the black anodizing on the chroziel that exhibits the "un-contamination". I don't know who coined that term, but, I find it rather laughable. Contamination, indeed! All objects reflect light, to one extent or another. If one thinks in terms of the three primaries, RG and B, objects will reflect each color in different strengths, absorbing some frequencies more than others. Infrared is not a single "color", per se, but a range of colors, or wavelengths. THe CMOS in the EX1 responds differently to different wavelengths, as well, resulting in the uneven interpretation of RGB channels, displaying red more than other wavelengths. No single filter is going to account for the unique infrared signature of all objects that appear black to the human eye. Filter design uses specific coatings to either absorb or reflect certain wavelengths. No single filter will block all the frequencies that are in the IR range. Furthermore, attenuation of undesireable wavelengths is not a step-function, but, rather, a gradient of attenuation as the frequency moves into the IR regime.

February 19th, 2009, 09:47 AM	#39
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Robert thanks for the info re:Tiffen. I found another possible candidate : Rosco US : Film/Video : Trucolor The problem is that they do not do them in 77mm circular format. I've contacted the company and they did tell me that they are aware of the green vignetting of certain filters and that theirs do not exhibit such green cast. They didn't mention however whether they have tested it on the EX series. They even went further in offering to cut a 77mm sized filter for me but that it was up to me to mount in on a 77mm thread. (I have no idea how to do it!!) If someone can confirm that they have used such a filter and that it works with the EX then I will consider buying a hood + filter holder (I'm not interested in matte boxes as they are too cumbersome for my run n gun work that I do). Anybody bought the Rosco?

February 19th, 2009, 10:15 AM	#40
Jay Gladwell Join Date: Jul 2002 Posts: 1,244	Great information, Brian. One would think (hope) that if Rosco has "solved" the problem, surely Schnieder couldn't be too far behind.

February 19th, 2009, 12:50 PM	#41
Brian Cassar Major Player Join Date: Jan 2007 Location: Malta Posts: 306	Jay, to be fair, Schneider did solve the IR contamination problem with their Tru-Cut 750 but for the RED camera only as it was found out that this filter does not work for the EX cameras. Rosco are saying that their filter works well with no green cast but I suspect that they have been tested for the RED camera as well. The problem as I see it is that the EX series are so sensitive to IR that an aggressive filter like the 486 will cause a green tint and anything less in IR blocking power will lead to no effect just like the Tru-Cut 750. I fear that this problem will never be solved for the EX......

February 20th, 2009, 01:41 AM	#45
Leonard Levy Trustee Join Date: Feb 2006 Location: USA Posts: 1,684	Kevin, Thanks for posting those pics. Doesn't seem to do much though. I'm figuring I may get something like a 486 eventually. If it works OK except on wide lenses then it would at least be valuable in the event of an interview with a big exec wearing a black jacket. That's a place I could imagine the client getting touchy. No need for a wide there. Lenny