Just did a video for our local symphony of which I have tried the tru-cut 750, B & W hot mirror and finally the 486 on my ex1. The 486 is the only filter that made the tuxes black, both of the others had little or no effect. I did not notice any green fringing with the 486. So unfortunately I had to spend 600+ dollars to find a solution.

Just did a video for our local symphony of which I have tried the tru-cut 750, B & W hot mirror and finally the 486 on my ex1. The 486 is the only filter that made the tuxes black, both of the others had little or no effect. I did not notice any green fringing with the 486. So unfortunately I had to spend 600+ dollars to find a solution.

Thanks for posting the your findings, John. Can you tell us if you're using any of the picture profiles from the forum (like Bill R's)?

The green vignetting usually happens when wide angle is used. If you zoom in somewhat as your concert shot is, you shouldn't get the green fringe. If you were setup on stage, you probably would have gotten fringing.

hi, does anyone have a link to purchase the 486 in the UK?

hi, does anyone have a link to purchase the 486 in the UK?

I bought mine thru Amazon.co.uk They do not actually sell it themselves but it is sold via their website thru someone else on their behalf. They do not have the slim fit but the hood still fits perfectly on the non-slim filter.

Here is the link: http://www.amazon.co.uk/B-W-77mm-UV-Infrared-Filter/dp/B000N8IMZO/ref=sr_1_1?ie=UTF8&s=electronics&qid=1235479909&sr=8-1

Hey guys,

Been watching this thread for awhile... I have the b+w 77mm uv filter (#010).

the one I have is for uv only but will not correct for the infrared issue inherent in cameras with digital sensors... correct? Will the b+w 77mm 486 uv/ir filter correct for both uv and infrared issue on my ex3? And can I also leave it on my camera at all times for lens protection?... or will it create other problems i.e. like shooting at night.

thanks

Greg

I intended to replace my B+W UV filter which was acting as a lens protector with this 486. However considering that this 486 produces this ugly green vignetting at wide angle, I decided to put it on only when I encounter the IR contamination problem, for the rest of the time I will keep on the B+W UV filter.

Hey guys,

Been watching this thread for awhile... I have the b+w 77mm uv filter (#010).

the one I have is for uv only but will not correct for the infrared issue inherent in cameras with digital sensors... correct? Will the b+w 77mm 486 uv/ir filter correct for both uv and infrared issue on my ex3? And can I also leave it on my camera at all times for lens protection?... or will it create other problems i.e. like shooting at night.

thanks

Greg

Greg,

The UV does not correct for IR contamination. The UV/IR does both however I do not recommend it for full time use given its limitations at full wide angle. Unfortunately you need both but don't use them at the same time.

Ryan Avery
Schneider Optics

Thanks Brian :)

I've been watching this thread with great interest for some time now and I appreciate the research conducted by all of you. I particularly appreciate Ryan and Schneider Optics for going way out of their way to help solve an issue that Sony should have stepped up to the plate for, long ago. Tiffen used to care like that, but it's not the same over there any more. Unless, maybe, if you're Spielberg.

Although I love my EX1 and EX3 I have spent many hours color correcting blacks clothing and fortunately, my clients have not yet complained. I have found that the "color match" plug-in in the Boris CC filters can usually return black clothing from red to very close to original black, (without killing everything else) by simply adjusting the "Red - shadow source" to a higher number. This combined with your normal color correction will usually save the day, but not always. Unfortunately, some fabrics just react so strongly to infrared light that the jacket may not match the pants of the same suit.

I too tried several filters to right this problem at significant cost, but to be honest, the camera has worked so well and looked so good in most other situations that I can't complain. It has helped us go places we couldn't previously afford to go in this business.

Ok That's my two cents.

Chuck,

I do appreciate what ryan has been doing a great deal, but don't count Tiffen out.
I recently talked to them at a trade fair in San Francisco and they brought a whole group of new "Hot mirror" and "Hot Mirror IR ND" filters designed specifically for the Red and other video cameras. They have also been doing their homework on this one though no one ahs shown our little camera the attention that Ryan so generously has.

As for our beloved camera manufacturer....

Lenny Levy

As an owner of an EX-3, I have noticed reddish blacks and not loved it, but being very happy with the camera otherwise, didn't ruminate too much over the problem. This thread has been extremely enlightening about the true import of the problem and about the range of present solutions and their limitations.

It has also stimulated the manufacturers (some anyway) to greater efforts and made us endusers aware of the possibility of more optimal filters in the pipeline.

Having read all the posts, I've elected not to jump the gun and buy the 486 or anything else, but to patiently wait for Schneider, Tiffen and Rosco to sort things out and give we thousands of EX owners what we need to get great results with our cameras under almost all conditions.

Thank you Chris Hurd for such a great forum, and congrats on your role in getting the ball rolling on the SI camera!

Tip McPartland

The green vignetting usually happens when wide angle is used. If you zoom in somewhat as your concert shot is, you shouldn't get the green fringe. If you were setup on stage, you probably would have gotten fringing.

Here is a stage shot at full wide, to me an acceptable image in comparison to burgundy tuxes or brown and some black.

Thanks for posting the your findings, John. Can you tell us if you're using any of the picture profiles from the forum (like Bill R's)?

720/60p BBC Video setting stepped down 1/2 stop. 3200k preset for color temp. Still quite haven't figured out the best way to deal with downlighting and bald heads...

yeah, I noticed that too. but with the wide angle vignetting that filter seems to produce, it did not seem like the ideal solution. the IRNDs without Hot Mirrors seem more versatile and effective. I've ordered one, and will post my experience when I've had a chance to use it.

which one did u order?

What's recommended though for indoor applications that don't need ND?

which one did u order?

Well, I had originally ordered a .9 IRND. But when I called to add some additional items to my order, I found out that Tiffen does not make that filter in a 4x4, and they would have to cut it custom which would take up to two months. (the original order was accidentally made as an IRND WITH Hot Mirror, which is apparently available)
So I canceled the order, and am in limbo at the moment. I really didn't want to wait two months for the filter.....

Regarding shooting indoors without ND filters, I would think that another approach would be to use lights that have a reduced IR signature like solar spectrum Alzo Digital phony HMIs (actually HID) lights that run much cooler, their "higher color temperature" notwithstanding. Also solar spectrum fluorescent or better yet LED instruments would give you less IR with which to cope.

This might be one reason that Sony is selling LED on-camera lights.

Tip McPartland

Dare I say this?

I think Adam's methodology is possibly flawed. Look at his first shot, no ND filter and no IR contamination. The problem he's trying to fix is different to the one we're trying to fix.
Also his test fabric is synthetic, we know that certain fabrics don't show up the problem.

By adding ND filters he's induced a different kind of problem where the sensor and it's filters are swamped by IR as the external ND filter doesn't cut IR. We see IR problems in all of the frame including the chart. This is not the same problem that we're having. Sure it could be a problem as well if adding external NDs.

Dare I say this?

I think Adam's methodology is possibly flawed. Look at his first shot, no ND filter and no IR contamination. The problem he's trying to fix is different to the one we're trying to fix.
Also his test fabric is synthetic, we know that certain fabrics don't show up the problem.

By adding ND filters he's induced a different kind of problem where the sensor and it's filters are swamped by IR as the external ND filter doesn't cut IR. We see IR problems in all of the frame including the chart. This is not the same problem that we're having. Sure it could be a problem as well if adding external NDs.

This is exactly what I think.

1. I don't have any serious problems in sunlight, only tungsten which implies lowlight - thus using ND is out of question

2. I never have everything contaminated, just some specific, black or dark blue materials

3. I have found that instead of using 3200K WB (typical for tungsten), it's enough to dial WB down to some 2800-3000K and the problem is gone, with only a little overall impact on the remaining colours - usually fixable in post.

4. Re: using LED, or another cold light, instead of tungsten: the rendition of people's faces it creates is a much more serious problem that the tungsten IR contamination of their tuxedos!

This is exactly what I think.

1. I don't have any serious problems in sunlight, only tungsten which implies lowlight - thus using ND is out of question

2. I never have everything contaminated, just some specific, black or dark blue materials

3. I have found that instead of using 3200K WB (typical for tungsten), it's enough to dial WB down to some 2800-3000K and the problem is gone, with only a little overall impact on the remaining colours - usually fixable in post.

4. Re: using LED, or another cold light, instead of tungsten: the rendition of people's faces it creates is a much more serious problem that the tungsten IR contamination of their tuxedos!

I'd have to disagree about 4). We use nothing but daylight balanced fluro, LED or HMI lights and everyone of our users are very happy over how good color rendition is. That's on top of the reduced heat and power requirements. So happy in fact we've just doubled the number of such lights we have on offer, despite the state of the economy we cannot meet demand at times. These lights have been used with just about every video camera out there and to shoot 35mm, 16mm and stills.

I'd also point out that I haven't seen a tungsten lamp in a local television studio down here in a long time. I am of course talking about light sources designed for television and film. Certainly there's no shortage of cheap "daylight" lights with poor CRI that can indeed give bad skin tone.

Bob,

I only meant a situation where an on-camera fill light somebody mentioned above is LED, and the rest of lighting is a typical, home tungsten - this is when balancing the WB is extremely difficult, and skin suffers most (or you get everything else reddish if you set your WB high).

For a fully controlled lighting environment, you're right of course.

Fair enough, You know I could tell you the solution to that problem but I know it's probably our of your price range.

I just took the 486 off my camera and tried shooting various black fabrics in full sun. No sign of IR problems that I could see. From all the screenshots that I've seen of IR problems under sunlight they're all taken when the sun is very low in the sky. I suspect at those times of day the shorter wavelengths are more filtered by the atmosphere.

Based on Art Adams' article, it seems that the problem isn't IR. Otherwise the filters designed to cut wavelengths longer than 700 nanometers would have the desired effect. They didn't.

Instead, he seems to have discovered that a filter which attenuates wavelengths longer than 680 nanometers appears to work well.

B&H does have a Tiffen filter that might work. But it's still an ND filter that cuts a full stop: Tiffen | Neutral Density 0.3 (ND) Infrared Glass | 45650IRND3 (http://www.bhphotovideo.com/bnh/controller/home?O=workaround.jsp&A=details&Q=&sku=572940&is=REG)

I can test to see if an LED light helps reduce the problem. I have a set of Cool Lights and the spectral distribution of the light has a significant dropoff after 610 nanometers. Maybe I can do a comparison of a few black objects shot under full CTB tungsten and the daylight LED.

I posted charts comparing the Cool Lights LED to full daylight here:
http://www.dvinfo.net/conf/photon-management/141864-new-coollights-led600-arrived-today-5.html#post1018808

I think I can confirm that the issue is not caused by typical IR wavelengths. I pointed a remote control at my EX1 and with the 486 filter on saw nothing. With the 486 off I could just see the LED blink but it was quite faint. My other camera with the internal IR cut filter out of the path (Nighshoot) the IR LED in the remote lights up very brightly. Also I noted that the EX1 showed the IR LED as white so it's getting in through all the RGB filters on the photodetectors roughly the same amount.
I don't know the wavelength of these IR LEDs, they typically seem to be around 800nm to 900nm.
So I think what Adam Wilt has confirmed is what Ryan Avery said some time ago. The red filters on the sensor are still letting wavelengths just below visible red through. That might have a deliberate move by Sony to get more sensitivity out of the sensor. Cutting it right off at the edge of the visible spectrum many have also attenuated some of the visible spectrum as well.

So really I think we're back to square one. We need a filter with a very sharp cutoff at 680nm out to at least 720nm. Any wavelength longer than that and the camera is already filtering that out.
Now the Tiffen filter according to Adam is using a complimentary color filter and it has to match the ND filter, that's all good but doesn't give us a filter we can use to cure the problem with the camera at all.
I'd also suggest that the 486 is not a typical "hot glass" filter. We have a ND 1.5 and ND 1.8 hot glass filter and the coating on the front looks just like a mirror, I could use it to check my makeup.

To put it simply , Adam has confirmed the nature of the problem, we still do not have a solution. Shooting stage shows with a ND1 filter on the camera even if it cured the problem is not an option, period.

This twist in this issue is very interesting but confusing as well. I cannot understand why in the test only ND IR cut filters were used. The problem is more accentuated under halogen lights than when filming in broad daylight. So any loss of light due to ND filter is unacceptable especially when shooting under available light (and not controlled lighting).

Can someone explain whether these Tiffen ND IR filters can be produced without the ND component in them - just IR cut only? Or is it not possible to have an IR cut filter which works well without some ND inside it? The 486 does not have any ND but then again it does not work well.

Piotr I have to disagree also with you on point No.4. I used to say the same thing like you said but after receiving my new Zylight 90 just yesterday I will not use any halogen on-board light again. The Zylight 90 is the LED lamp to use for ENG. It's true that it is very expensive (it took me a year to decide to buy it) but the ability to switch the colour temp at the touch of a button without using any light reducing coloured gels in front of the led's is fantastic. I haven't used it in an assignment but from the tests I did yesterday it's absolutely amazing! I bought it specifically to eliminate the halogen light on board of the EX3 which was causing too much contamination.

To put it simply , Adam has confirmed the nature of the problem, we still do not have a solution. Shooting stage shows with a ND1 filter on the camera even if it cured the problem is not an option, period.

I couldn't agree more with this last statement, Bob (with a little correction - we're not talking Adam Wilt's article here, but that of Art Adams :)).

However - after having tried the screw-on 486 and 489 - I'm now having a 4x5.65" filter from a manufacturer whose name I'd prefer not to reveal at the moment. I have just completed a quick and dirty series of tests, and here are my results...

1. YES, even in daylight at 5600K, the blacks CAN be a bit contaminated - just compare the first pair of my grabs (upper left - no filter, upper right - with filter X)

2. In tungsten light at preset 3200K, EVERYTHING is too red - but still the middle right picture (with filter X 3200K) shows some improvement over no filter (middle left) (BTW, sorry I forgot to re-focus on the main subject - the bag - after I had to open up the iris due to lower light)

3. As I said before, dialing WB down to 2700K (to balance at the white card) allows to minimize the red contamination (bottom left - no filter), and the filter I tested makes the black ALMOST completely black (bottom right).

Conclusions:

1) 3200K is commonly used as the right preset for tungsten lighting; looking at the grabs, it's obviously too hot - always do white balancing before actual shooting! It seems to have much stronger influence on the alleged "IR problem", than using a Hot Mirror filter...

2) The B+W 486 filter can get rid of ALL contamination (see my comparison grabs in another thread); should it not produce the ugly, greenish vignette at wide angles, it would be the best solution for the EX cameras... Just what kind of filter is it ?!!

Comments welcome!

It's true that it is very expensive (it took me a year to decide to buy it) but the ability to switch the colour temp at the touch of a button without using any light reducing coloured gels in front of the led's is fantastic...

Sure - if you can change the light temperature, it's great (and expensive:))...

I used to have the Sony on-camera LED light (no 3200 filter - just 5600K; 4000K with dimmer on), and in situations I mentioned above (where the surroundings were more towards 2700 - 3000K), faces did look ugly.

Of course, I might have used some amber gelling, but then the lumen/watt ratio would drop dramatically down to a regular, halogen lamp that I'm using now. Much smaller and versatile!

3. As I said before, dialing WB down to 2700K (to balance at the white card) allows to minimize the red contamination (bottom left - no filter), and the filter I tested makes the black ALMOST completely black (bottom right).


Piotr, whenever I've encountered IR contamination (or whatever it is...), under halogen lights, I've always manually white balanced on a white paper and got a reading of about 2600-2700K. I never use preset and yet I've witnessed some horrible black-turned-brown fabrics. Seeing your test, I'm now wondering whether I should use the warm cards at all in such situation. I was intending to start white balancing always with the 1/4 Blue to warm a bit the picture but will need to do some tests as the warming effect might enhance the "contamination".

I'm also wondering why some people have stated that they are not seeing the green tint with the 486. Could it be some manufacturing inaccuracies that are producing the ideal filter unintentionally and unknowingly?

I think I found a temporary solution to this IR contamination problem. As I had indicated before I tend to film a lot under available light (without any fill in light) which on most time is predominantly halogen. This was obviously giving me loads of problems with black material.

I have just done a very quick test - I filmed a black t-shirt under available halogen light. This as expected turned to a brownish tint. I then switched on the newly bought Zylight 90 and since this is LED light the black t-shirt was restored immediately back to black! Even when I had dimmed the light to almost minimum, as long as a very small quantity of LED type of light fell on the black fabric, the problem disappeared (without the use of any filter). Please note that the Zylight was switched on the 3200K setting so as not to disrupt the white balance that had been set to the prevailing halogen light.

This means that unfortunately I have to change my style of filming and start using some dimmed fill-in LED light whenever there is halogen light as the main source of lighting. As I said this was a very quick test. I have yet to test it out in a proper shoot - but I'm expecting the same type of results that I had obtained today.

I'm also wondering why some people have stated that they are not seeing the green tint with the 486. Could it be some manufacturing inaccuracies that are producing the ideal filter unintentionally and unknowingly?

It took me a long time before I noticed it.
That's always the problem in this game, deciding what matters and what doesn't.
Looking at a couple of screenshots that Piotr supplied I can see it quite clearly however I believe the camera was not WB after fitting the filter so the whole frame does have a bit of green caste to start with, it gets worse towards the edges for sure. One reason it's not been so obvious to me is the filter is always on my camera, as are all the other ones in our fleet so the cameras are always being WB'ed with the filter on.
So again the question is not is it there, the question is does it matter. I'd suggest it doesn't as the eye is not naturally drawn to it. Maybe it'd be different if the subject was up against a white wall but such shots are rare. On the other hand people wearing black sitting large in the middle of the frame are very common. The visual effect of the 'IR' problem does seem very distracting to the average normal viewer as there's nothing naturally like it. On the other hand a bit of fall off or caste towards the edge of a wide shot mimics what is sometimes seen in the natural world.

The visual effect of the 'IR' problem does seem very distracting to the average normal viewer as there's nothing naturally like it. On the other hand a bit of fall off or caste towards the edge of a wide shot mimics what is sometimes seen in the natural world.

Well said - I fully agree with this reasoning. However on the other hand I remember the fuss that was kicked up on the very small vignetting that the early EX1's had and yet now we are creating a much larger and coloured vignetting.

I'm sure everyone's white balanced through 1/8 or 1/4 CTB to warm up their subjects. I used to do this and sometimes I would also add 1/8 green, can't remember the exact gel. I started doing this when I would have to shoot with existing fluorescent lights, but then I came to think a little less green was good for skin tones much of the time.

What occors to me is that perhaps a gel or combination of gels the same color as the fringing, or as close as possible, could be used during the white balance.

The result would be a neutral color balance where the vignetting would have been, and a bit less green/cyan in the center where the subject is. This might look nice, or at least nicer than a bias in portions of the picture toward the green side.

Tip McPartland

Generally outdoors I do not use any additional IR filtering (while Bob uses it as default), but it isn't true to say that the IR problem isn't present under 5600K lighting. Attached are two recorded in sunlight (white balanced internal camera ND filters) and the black artificial fibre is recorded black only with the BW486 filter.


Also, when suggesting that the default 3200K setting is too hot (which I haven't checked, I always WB) how was the colour temperature of the lights measured? Maybe they were not 3200K.

Can someone explain whether these Tiffen ND IR filters can be produced without the ND component in them - just IR cut only? Or is it not possible to have an IR cut filter which works well without some ND inside it?

It's my impression from Art's article that you can almost consider the successful filter to be a correction filter. All correction filters (all filters, really) involve a loss of light. The filter factor of an 80A is 2 stops. A one stop loss for a filter that corrects the IR "contamination" seems pretty reasonable and should be expected.

I'd be very curious to see the results from someone using the 0.3 filter.

By the way, I haven't been able to find anyplace selling the non-Hot Mirror version of this filter. Anyone have a suggestion?

Pete

It's my impression from Art's article that you can almost consider the successful filter to be a correction filter. All correction filters (all filters, really) involve a loss of light. The filter factor of an 80A is 2 stops. A one stop loss for a filter that corrects the IR "contamination" seems pretty reasonable and should be expected.

I'd be very curious to see the results from someone using the 0.3 filter.

By the way, I haven't been able to find anyplace selling the non-Hot Mirror version of this filter. Anyone have a suggestion?

Pete
Hello, Pete-
I'm not sure what size filter you want, but I know Filmtools in CA (Filmtools: Hollywood's source for grip, electrical, lighting, sound, video and film supplies (http://www.filmtools.com/)) can special order a non-hot mirror version in a 4x4. 4x5.65 are readily available, I've found them at a number of retailers, but for the 4x4, Tiffen has to apparently cut the filter upon order, which will take approximately two months. I guess they don't have enough demand for the filter in a 4x4 to have any ready to go. I'm not sure if it's available at all in a 77mm.

Also, when suggesting that the default 3200K setting is too hot (which I haven't checked, I always WB) how was the colour temperature of the lights measured? Maybe they were not 3200K.

This is a very important point, Serena - I didn't measure, I just used my EX1's 3200K preset. Could it be that the WB system in my specific unit is not calibrated well? Because it's obviously too hot for tungsten; when I balanced to the white card (not changing anything else), the WB settled at 2700K !

Can anyone confirm or deny the same happens with their unit(s), or is my unit defective?

It's extremely important to me to know whether I can trust the presets, as I often shoot live stage performances with other EX1's; of course we could balance all 3 to the same white card, but using a preset is much safer (I mean, with the WB switch set to memory A or B, it's all so easy to inadvertently knock the AWB button and lose the setting - while when it's in a preset position, it's 100% safe).

The difficulty with tungsten is that the colour temperature is quite sensitive to lamp voltage and age, so we can't be really sure about its colour temperature without measuring (hence the colour temperature meter). You can measure the voltage when the lamp is on and if that matches the designated lamp voltage then you won't be far out. Our supply here, for example, is supposed to be 230v AC, but varies between 220 and 245 (depending on district load) and I have seen it below 210. Stage lighting is generally on dimmers, so the CT can vary quite a bit across the stage and in time.
Today I did run a test using a RedHead QI and the camera WB, 3200 preset and colour temp meter all agreed within +/-100K . The EX1 WB gave me 3100K and I couldn't see the difference switching to the preset.
The thing is to make sure all cameras match in their settings, because matching in post is a pain. You can, as you know, pre-set any CT you find appropriate, so the 3200 factory pre-set isn't operationally critical.

Piotr,
I'm having trouble identifying exactly what problem your having because I don't know what lights you were using or for that matter how much background you may be bringing to your understanding. Please excuse me if it sounds like I'm talking down here.

It looks like you you shot the test of the chair under ordinary household tungstun bulbs which are not 3200 but closer to 2600- 2900K so of course the picture would appear red.
Alternatively Serena is right that if your voltage is lower than what even professional photo lamps are rated for (usually 3200) the same thing would happen.

This has nothing at all to do with IR contamination, just ordinary white balance and color temperature. IR is something that only affects some fabrics in an otherwise well color balanced shot.

It is interesting though that people with the EX on these boards have been complaining mostly about IR under Tungstun light rather than in daylight while using ND while complaints about the RED seem to center more about ND problems. I need to do some testing myself on this soon.

Its obvious that flourescents might not produce the same IR that tungstun but that is only a very limited solution for most people. Though for now might be something to keep in mind if you have an important shoot that you have the ability to shoot with flos.

Lenny Levy

Lenny,

No problem with talking down to me at all :)

I probably wasn't clear enough, but I do realize the middle 2 grabs posted above (at 3200K preset) are too warm due MAINLY to bad WB, not IR contamination. Basically, the left 3 grabs are without any filtering, while the 3 to the right - with some Hot Mirror filter I'm testing now (which only has none to mild effect, BTW).

If I discussed the 3200K preset vs 2700K measured CT with Serena has been because, in fact, I started worrying about my unit's WB presets being off - without any connection to the IR contamination.

Your post, however, helped me stop worrying as indeed, 3200K is more for a direct halogen light, and my shots were taken under regular home tungsten (plus red curtains in the window to block daylight). So, the 2700K is absolutely a more realistic figure for the true CT here!

Well, I did put a disclaimer in my post above these were very "quick & dirty" tests - but I should have taken more time (and thought) posting them, anyway!

Nevertheless, I think my conclusions still hold true:

- the W+B 486 filter I tested earlier is far more efficient than my currently being tested one, as it can get rid of all and any red contamination (I deliberately don't call it "IR"), but sadly is unacceptable due to the greenish vignetting at wide angles

- proper WB is essential for minimizing the red contamination, with a filter as well as without one

I guess you can agree :)

It's occurred to me that the EX1 may be exhibiting a sensitivity to a type of "metamerism" or the way a pigment or dye changes its appearance under different types of lights.

People who do critical color printing always judge the quality of a print under lights that have the spectral distribution of daylight. These lamps are carefully produced and tested, and they're checked during their lifespan to ensure high quality control. Pigments that look blue under one type of light might appear almost purple under another type of light. So printers who are picky about quality and consistency always use a standardized light source under controlled conditions (a viewing booth) to judge their work.

Because of its extended sensitivity to wavelengths in excess of 650 nanometers, tungsten lights would tend to exaggerate that quality in certain materials. Tungsten lighting's spectral distribution is mostly in the longer wavelengths. That's why what looks "black" to the human eye in tungsten light looks "red" to the EX1.

Under LED lights and fluorescents, those same materials might not exhibit the same degree of redness. And, of course, with a filter that attenuates wavelengths longer than 650 nm, that redness is also reduced.

Dean,

I think that you might correct here. I often see what the EX1 sees - a redness in the blacks of some "black fabrics" under some lighting conditions. The EX1 sees it more than me, but I can clearly see it. This does not extend to all fabrics (such as suits), but the synthetics such as nylon are the worst offenders for redness to my eye.

I guess that everyones vision is slightly different.

Dean - yes,

- the second issue of course is the ND problem , because even though you are under daylight outdoors, , normal ND filters don't cut the IR portion of the spectrum so the IR portion cumulatively and disproportionally increases with increasing strength of ND filtering.

Art Adams only addressed the latter question in his post. I've been trying to contact him privately about it but haven't gotten a response yet.

It's true that our vision doesn't simply stop working at a certain wavelength anymore than our hearing stops at a given wavelength of sound. No doubt it also varies over the population. Certainly some IR LEDs used with security cameras are visible if you look into them, you'll see a dull red glow. I think we retain some sensitivity out to 800nm.

The problem is that such wavelengths are all simply seen as red by our cameras, keep in mind that neither video or film records the wavelength of light, only the relative amounts of the primary colors.

There's one aspect to this not mentioned so far. If the EX did not retain some sensitivity beyond the visible spectrum that would preclude its use for night time wildlife photography. IR illuminators would be useless.
One type of illuminator seems to use 940nm LEDs. These are totally invisible and only work with cameras with no IR filter or one where the IR filter can be removed. This is the best system as silicon is most sensitive at 1000nm.
The other illuminator uses 850nm LEDs for cameras with fixed IR filters. These LEDs can be seen as a dull red glow. I might buy a cheap one of these to see how they perform with the EX.

Considering that normal ND's cut up up to some 680 nm, using one outdoors should create a "hole" between 680nm and where the internal hot mirror starts to act (700-750) for long reds to leak into the sensor, as the one that exists when shooting indoors, without any ND but under a lighting which is low and shifted towards red when compared with sunlight.

And indeed - today I took a closer look at some black fabrics notorious of becoming red in tungsten, but put on the ND filter and shot it in the sunlight: it's maroon, as expected !

So it seems we understand now what's happening; what's more - it's probably not another Hot Mirror that we need to prevent it (as Art Adams points out in his another article here:

ProVideo Coalition.com: Stunning Good Looks by Art Adams | Cinematography (http://provideocoalition.com/index.php/aadams/story/red_hot_mirror_shoot_out/P0/))

To the F35 (and also EX) owners, he says:

"don’t buy Hot Mirror filters for your Genesis/F35 because it’s a waste of money."

But unfortunately, in all those articles the cure, proposed for these cameras, are special kind of ND filters from Tiffen; what we REALLY need is an equally efficient filter without any ND component, as we need it for low-light shooting!

Considering that normal ND's cut up up to some 680 nm, using one outdoors should create a similar "hole" between 680nm and where the internal hot mirror operates (750?) for long reds to leak into the sensor, as exists when shooting indoors, without any ND but under a lighting which is low and shifted towards red when compared with sunlight.

And indeed - today I took a closer look at some black fabrics notorious of becoming red in tungsten, but put on the ND2 filter and shot it in the sunlight: it's maroon, as expected !

So it seems we understand now what's happening; what's more - it's probably not another Hot Mirror that we need to prevent it (as Art Adams points out in his another article here:

ProVideo Coalition.com: Stunning Good Looks by Art Adams | Cinematography (http://provideocoalition.com/index.php/aadams/story/red_hot_mirror_shoot_out/P0/))

To the F35 (and also EX) owners, he says:

"don’t buy Hot Mirror filters for your Genesis/F35 because it’s a waste of money."

But unfortunately, in all those articles the cure, proposed for these cameras, are special kind of ND filters from Tiffen; what we REALLY need is an equally efficient filter without any ND component, as we need it for low-light shooting!

Take a careful look at page 5 of the article.
The first shots with 0.9 ND filter show extreme red shift in the fabric on the right side of the chart. I'd suggest the ND filter is making the problem worse as it's cutting visible and not far red i.e. it's in effect adding gain to the far red.
Now look at the last two shots. There's still some red shift in the fabric. The extra dye has corrected the ND out to the far red. As Art says the amount of dye has to balance the ND. Probably if it doesn't either the red shift is back or it introduces a shift in the rest of the spectrum. It's tempting to hope that a simple and cheap dye filter will cure our problem but I suspect it isn't that simple.

The 486 is a pretty complex filter with I think over 30 layers of different materials, probably each one provides a narrow notch filter which is why it can achieve such a sharp cutoff just outside the visible spectrum. Maybe our ideal filter doesn't need so many layers as we don't need IR cut however to achieve such a sharp cutoff I think we'll still need this kind of filter and that'll mean some degree of color shift at low angles. Tilting the 486 and watching the rainbow of colors it reflects I'm amazed there isn't more shifts with this filter.

Take a careful look at page 5 of the article.
The first shots with 0.9 ND filter show extreme red shift in the fabric on the right side of the chart. I'd suggest the ND filter is making the problem worse as it's cutting visible and not far red i.e. it's in effect adding gain to the far red.

That's exactly what I was trying to say - sorry for my English :)

As to the 486, it's amazing indeed how effective it is - both under tungsten, and sunlight (even with ND on). However, the low angles vignetting is not the only problem that led me to sell it away (cheaply); as I'm often using my 35 mm adapter/lens, I needed a 4x5.65" version (rather than a screw-on) to be put as the first optical element in my matte box.

From the series of Art's articles it seems that the answer would be an IR filter like Tiffen IR ND (not a hot mirror, i.e. without the dichroic coating), that cuts at some 680 nm. Not only is it the most effective on the red contamination type found on the CineAlta series, but it doesn't introduce any vignetting at wide angles. And, it's much cheaper than hot mirrors!

However, I'd prefer such a filter without any ND component to it, so that I don't lose any light at all - now, does such a beast exist?

The weakest ND one I found is : http://www.bhphotovideo.com/c/product/572940-REG/Tiffen_45650IRND3_Neutral_Density_0_3_ND_.html - just one stop light loss. The catch is that - as Art points out - those filters cannot be combined with other ND's, so we're sort of trapped...

The ideal solution would be if Sony (the upgrade kings) offered to replace the built-in ND filters with IR-ND filters. Of course they'd also change the ones on the assembly line, calling them "EX-1B" and "EX-3B" and charging more.

"The ideal solution would be if Sony (the upgrade kings) offered to replace the built-in ND filters with IR-ND filters".

Here, here! I agree.