View Full Version : Filter for IR contamination


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Anthony McErlean
March 23rd, 2009, 09:14 AM
So I suppose theres nothing for it but to get the B+W 486 filter for my EX3 advised by Brian, (thanks)

I think Brian you supplied this link of us in the UK.. B&W UV-IR Digital (486) 77....

B&W UV-IR Digital 77: Amazon.co.uk: Electronics & Photo (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)

I saw in a post Brian you thought your LED On-board Camera light might have helped the blacks to stay black. Have to tested any more on this.

Thanks.

Brian Cassar
March 23rd, 2009, 09:31 AM
Anthony I found out two things lately:

1)If a potential black fabric which is turning into brown in a tungsten lit room is blasted with light from an LED on board lamp, then the black becomes black again. The reason being that LED light is overpowering the halogen / tungsten light which has a component of IR. That is why I found the Zylight 90 so effective as I can dial in any colour temp that I need so as to match the prevailing light. I did not have time to experiment much on this but I did see this effect. I generally prefer using the 486 and be able to film under the available light rather than switching on the on-board light.

2)Lately I was convinced in buying and using the warm cards. The footage does become much nicer than standard white balancing on a piece of paper. However I've noticed that if one uses the 1/2 warm filter, this will tend to enhance the IR contamination if filming under tungsten or in daylight.

Incidentally for just one instance I thought that I have solved this issue. I white balanced on the grey card that is included in the warm cards pack and I managed to see a black t-shirt as black under halogen light. I just couldn't believe it and I took another white balance and this time although it was the same colour reading of 2300K the t-shirt turned brownish. I've tried several times to get the same effect but couldn't. This one off event led me to re-confirm what others were hinting (I believe Piotr was one of them) that this IR contamination might be somehow linked to white balancing as well. It is not just a question of white balancing but probably a series of other things.

Anthony McErlean
March 23rd, 2009, 09:45 AM
Hi Brian

I white balanced on the grey card that is included in the warm cards pack and I managed to see a black t-shirt as black under halogen light. I just couldn't believe it and I took another white balance and this time although it was the same colour reading of 2300K the t-shirt turned brownish....

Thats interesting, you could be on to something there.

I read somewhere that a newspaper, a fews days old, was good to white balance on, I don't know, I never tried it. A polystyrene cup was something else that was suggested.

Just wonder after reading the posts regarding this, have Sony themselves comeback with any new info.

Dave Morrison
March 23rd, 2009, 10:27 AM
It sounds to me like what you are seeing is the side-effect of "fooling" the camera. For example, by using the off-color white balance cards (or the slightly yellowed day-old newspaper), you are skewing the white balance of the camera slightly toward the blue end of the spectrum causing the blacks to "cool down" (along with all the other colors, btw) thereby making the brown-blacks appear cooler and "blacker", no?

Brian Cassar
March 23rd, 2009, 10:58 AM
Oh...I forgot to mention one very important observation. When I managed to restore black to black for just one instance only by taking a WB reading from a grey card, the reds in general were very much muted (obviously). Which leads to more speculation whether it is really a case where the EX cameras are very sensitive to the red colour. So in order to get decent black one will loose the vividness of the red color. Hence that is why probably some people have suggested to work out a picture profile for this issue. However this will be at a cost for the overall warmth of the picture since the reds would be curtailed.

Anthony McErlean
March 24th, 2009, 07:50 AM
I'm looking for the B+W 486 filter recommended. Not really sure what to order here in the UK but was wondering if this is the correct filter to get. £62.96

B+W 010 UV MRC SL 77mm Ultra Violet Filter (Multi-Resistant Coating - Slim Mount) (http://www.fotosense.co.uk/shop-by-brand/b-w-filters/b-w-uv-filters/b-w-010-uv-mrc-sl-77mm-ultra-violet-filter-multi-resistant-coating-slim-mount.html)

Thanks.

Derek Reich
March 24th, 2009, 08:17 AM
Hi, Anthony-
That filter you listed is incorrect. That one is a simple UV filter which will do nothing to reduce the IR contamination. This is the one you want:
B+W 486 UV/IR MRC SH 77mm Ultraviolet / Infrared Cut Filter (http://www.fotosense.co.uk/b-w-486-uv-ir-mrc-sh-77mm-ultraviolet-infrared-cut-filter.html)

I have discussed this at length with Ryan Avery, the US rep for Schneider (B+W) filters. While he admits that there currently is no 'holy grail' filter for the EX for IR contamination, the 486 is the best option with the caveat that you cannot shoot full wide without some cyan vignetting. If you keep that in mind and shoot accordingly, this seems like the way to go. I have ordered the 4x4 version of this filter (called the Tru-Cut 680) and will post some results when I have had a chance to test it. I am hopeful that in most circumstances this filter will do the trick. One other thing: since this is a 'hot mirror' filter (it has reflective coatings) it MUST be the first filter light hits, so if you are using any other filter along with this, it must be positioned behind the 486.

I was tempted to try the Tiffen IRND filters described here:
ProVideo Coalition.com: Stunning Good Looks by Art Adams | Cinematography (http://provideocoalition.com/index.php/aadams/story/ex1_ex3_ir_filter_shoot_out/)
but in the end went with Ryan's suggestion. The Tiffen filters cannot be used with any other ND filter (even the built-in ones on the camera) which severely limits the versatility of the filter, unless you have unlimited resources and can afford several of these filters each with a different level of ND. At around $300US each, that wasn't an attractive option.

Anthony McErlean
March 24th, 2009, 08:38 AM
Thank you Derek for giving me the correct link and the tips regarding using other filters along with it.

So do you think the Tru-Cut 680 might also eliminate cyan vignetting in the wide shots.

Thanks again.

Anthony McErlean
March 24th, 2009, 08:57 AM
Should have asked, does this filter stay on the lens at all times or are there certain times its needed, and fitted then.

Thanks.

Piotr Wozniacki
March 24th, 2009, 10:01 AM
Should have asked, does this filter stay on the lens at all times or are there certain times its needed, and fitted then.

Thanks.

Anthony,

When I first bought the 486 (screw-on) filter, I was hoping to be able to keep it permanently on the lens. However, considering the vignetting at wide angles and the fact no other optical element must be present in front of it, I soon realize this is not viable.

BTW, Derek is buying the 4x4" version to be used with a matte box, I assume, which is the best solution especially when one is using a 35mm adaptor/lens. If only some manufacturer came out with a non-hot mirror (i.e. without the dichroic coating which causes vignetting), neutral-ND version...

Anthony McErlean
March 24th, 2009, 10:21 AM
Anthony,

When I first bought the 486 (screw-on) filter, I was hoping to be able to keep it permanently on the lens. However, considering the vignetting at wide angles.... I soon realize this is not viable

Thanks Piotr for that, not the owner of a EX3,.. just yet, so when exactly does this filter be used, indoors or out.

Just placed the order for the 486 filter. Thanks Derek BTW.

Piotr Wozniacki
March 24th, 2009, 10:30 AM
Mainly indoors, as the red contamination problem is most pronounced under tungsten light.

However, it can also be visible with some fabrics under day light, especially with strong ND filtering.

Anthony McErlean
March 24th, 2009, 10:42 AM
Thanks again Piotr, so theres a bit of trial and error till you get the hang of it :)

Leonard Levy
March 24th, 2009, 10:53 AM
Is the 486 as effective outdoors as it is indoors. Has anyone tested that yet?

Piotr Wozniacki
March 24th, 2009, 11:04 AM
Yes Lenny - it's equally effective (100%).

Brian Cassar
March 24th, 2009, 12:56 PM
Thanks again Piotr, so theres a bit of trial and error till you get the hang of it :)

Actually it is very easy - I keep the 486 in its protective plastic case in my pocket all the time - if and when I encounter the IR contamination I just screw it in. Yes it can be seen in daylight but is not so pronounced as under tungsten lights. Although it is true that the 486 gives you a slight green vignette at extreme wide angle, I'm pretty sure that in the case of event filming, the client will not notice it. We notice it because we know about it and we try to look for it. But if you are viewing the end product on a full HD 50" tv I'm sure that your eyes will mainly focus in the middle of the screen and will not notice the extreme edges. ...just my impression....

Anthony McErlean
March 24th, 2009, 01:05 PM
Actually it is very easy - I keep the 486 in its protective plastic case in my pocket all the time - if and when I encounter the IR contamination I just screw it in. ....

Hi Brian, again not the owner yet, of the EX3, so this can be seen right away in the EX1/3 viewfinder, blacks aren't black, so just screw the filter on when this happens.

Derek Reich
March 24th, 2009, 01:48 PM
Piotr is right.... I ordered the 4x4 version of the 486 because I use a matte box. I feel it's much easier managing and applying filters that way, plus I already own a large array of 4x4 filters. Also, then they can then be used with any lens I happen to mount on the camera.
I also agree with Piotr that you should not just leave this filter on all the time.... there are several reasons why which have already been addressed. It's best to have it on hand, and use it if/when you see the issue. Kind of like using a polarizer.... there are certain applications when a polarizer works great, but it's not something you'd want to keep on all the time. (speaking of polarizers.... make sure if you use one on the EX that it MUST be a 'circular' polarizer, and NOT a 'linear' polarizer. That is a whole other issue.....

I have seen the IR contamination in all lighting conditions, so there is no 'ideal' circumstance for this to occur. I have seen it in daylight, tungsten light, even HMI lighting. I just plan on popping the Tru-Cut filter in when I see a problem, otherwise it's in my filter kit standing by.

I haven't received my filter yet, but will be more than happy to share my experience with it when it arrives.

Happy shooting-

Brian Cassar
March 24th, 2009, 11:04 PM
Hi Brian, again not the owner yet, of the EX3, so this can be seen right away in the EX1/3 viewfinder, blacks aren't black, so just screw the filter on when this happens.

Yes Anthony. Once you are aware of the issue you'll see it immediately in the colour viewfinder and then you'll just pop on the filter.

I would love to use 4x4 filters instead of screw in type (especially in this case) but unfortunately do not wish to buy a large matte box just for the filters. Also I do not wish to loose the function of the lens hood as I like the ability to close of the hinges when not filming. I've seen that the Z5 has a hood supplied with the wide angle accessory that accepts large filters. Does anyone know of something similar - maybe a slim filter holder that screws in front of the lens and then the hood can be mounted on top of it?

Daniel Alexander
March 29th, 2009, 08:20 AM
I not long recieved my 486 filter and thought I'd share my experiences to add to the collection. I done alot of testing to see if it really cured the reddish brown problem under all sorts of different lighting, different fabrics etc and I can report that i was able to get ALL my blacks looking black however there are side effects. I actually filmed a very short clip to demonstrate how effective the filter was along with my thoughts on the side effects etc, you can check it out at 486 filter test 'quick & dirty' on Vimeo (http://www.vimeo.com/3900978)

I plan to film a proper testing at some point, this clip really is only to demonstrate what the filter does for those wondering if they should spend the money or not. Hope it helps

Anthony McErlean
March 29th, 2009, 10:16 AM
Thanks for that link Daniel, well done. I can see it fixes the blacks and I can now understand why its best to use it only when needed. I did see the white wall just to the left of the chair (our left) turn a very light lime green and the out side shot (fence) I seen the filter darken the picture slightly. I thought I saw a hint of green in the sky shot.

From what I seen its definitely need for the blacks but to keep it off when not needed.

I'm just wondering how I would work this out when I video my weddings. Grooms can have black suits, brothers and sisters of brides and grooms in family photos can and do ware black and if it turned out a different colour in the DVD they would notice this right away.

A few weddings ago the bridesmaids wore black dresses and the brides mother wore black.
So how would you go about dealing with that.

I think theres something badly wrong when we have to fit filters to correct this.

Ed Kukla
March 29th, 2009, 10:37 AM
I understand that the 486 HAS to be the outside filter, no filters in front of the 486. So a screw on can be problematic if you want to add another filter like a polarizer.

I don't find any 4 X 4 486 filters. Any leads?

Derek Reich
March 29th, 2009, 11:06 AM
I understand that the 486 HAS to be the outside filter, no filters in front of the 486. So a screw on can be problematic if you want to add another filter like a polarizer.

I don't find any 4 X 4 486 filters. Any leads?

That's because in the 4x4 size, the 486 is called a 'Tru-Cut 650'
(don't ask me why)
I got one just the day before yesterday through Filmtools in CA. I don't know if they stock it, or had to order it in, but Ryan Avery (the Schneider rep) was very kind to arrange for delivery of the filter. He mentioned several different retailers you can get one through. I just like Filmtools for my past experience dealing with them, but Ryan mentioned you can also get one through Abel Cine, Alan Gordon Enterprises, or Express Video Supply.
I haven't had a chance to play with it yet, but am optimistic that it's the best choice at the moment, with the understanding that it does have some shortcomings which have already been addressed at length in this forum.

Piotr Wozniacki
March 29th, 2009, 11:27 AM
That's because in the 4x4 size, the 486 is called a 'Tru-Cut 650'

Actually 680, isn't it Derek? If so, that would be for the 680 nm range that it's cutting at (unlike to 750 which is of the "Hot Mirror" type, and has proven to not be effective with the EX - or more generally, CineAlta - series of cameras).

BTW, do you happen to know whether its 4x5.65" version is also available?

Daniel Alexander
March 29th, 2009, 12:12 PM
Thanks for that link Daniel, well done. I can see it fixes the blacks and I can now understand why its best to use it only when needed. I did see the white wall just to the left of the chair (our left) turn a very light lime green and the out side shot (fence) I seen the filter darken the picture slightly. I thought I saw a hint of green in the sky shot.

From what I seen its definitely need for the blacks but to keep it off when not needed.

I'm just wondering how I would work this out when I video my weddings. Grooms can have black suits, brothers and sisters of brides and grooms in family photos can and do ware black and if it turned out a different colour in the DVD they would notice this right away.

A few weddings ago the bridesmaids wore black dresses and the brides mother wore black.
So how would you go about dealing with that.

I think theres something badly wrong when we have to fit filters to correct this.

I agree that its wrong we have to fork out for a filter that is going to affect so many shooting applications, its just crazy. Although the filter does have a slight green tint if I were shooting weddings I would make the sacrifice and just keep it on, because I'd rather deal with a shifted white point rather than a black suit turn red. In post I can pretty easily get my white balance sorted so the green tint is gone (if it was even noticeable which is questionable) but unless i do several secondary colour passes i can't turn the reddish brown suits back to black again.

Dave Morrison
March 29th, 2009, 12:37 PM
Daniel, what was the exact part number or catalog number of the filter you were using? This was the screw-in version, correct?

Derek Reich
March 29th, 2009, 12:56 PM
Actually 680, isn't it Derek? If so, that would be for the 680 nm range that it's cutting at (unlike to 750 which is of the "Hot Mirror" type, and has proven to not be effective with the EX - or more generally, CineAlta - series of cameras).

BTW, do you happen to know whether its 4x5.65" version is also available?

Yeah Piotr, you are correct. It is a Tru Cut 680.
Sorry for my brain-fart there.

Anthony McErlean
March 29th, 2009, 01:28 PM
I would make the sacrifice and just keep it on, because I'd rather deal with a shifted white point rather than a black suit turn red. In post I can pretty easily get my white balance sorted so the green tint is gone.

Would that greenish tint be noticeable against church windows or a shaft of sunshine on a church wall for instance.


... In post I can pretty easily get my white balance sorted so the green tint is gone.

So colour correction could sort out the greenish bits.

Perhaps this isn't as bad as I'm reading into it, I don't know. Just when coming from a camera were theres not bother like this, it makes you wonder.

David C. Williams
March 29th, 2009, 03:55 PM
The greenish tint reduces to nothing as you zoom in. The coating on the filter reflects different wavelengths at different angles, so full wide using the outer curve of the lens picks up light at a different angle. That's why you get a greenish vignette.

Daniel Alexander
March 29th, 2009, 04:30 PM
Heres a link to the exact filter to answer Dave's question B&W UV-IR Digital 77: Amazon.co.uk: Electronics & Photo (http://www.amazon.co.uk/B-W-UV-IR-Digital-486/dp/B000N8IMZO/ref=sr_1_1?ie=UTF8&s=electronics&qid=1238365031&sr=8-1).

Anthony I'm quite confident that you wouldn't have a problem with the green tint against any window or shaft of sunlight mainly because after white balancing with the filter already screwed on you can hardly tell the difference anyway, I mean from my tests I couldn't imagine the green cast being anywhere near strong enough to cause me a problem UNLESS i was filming against a white background at full wide (even then a short zoom in will solve that problem).

Yes colour correcting in post easily sorts this problem out and thank God it's as simple as using an eye dropper tool to tell your application what colour white is supposed to be and because I usually balance my pictures with a colour correcting wheel anyway I don't find myself having to do any extra work which is good. But i stress again that I doubt you'd even need to do this as in most cases it's only visible if you have pre-filter footage to compare it next to.

All in all i am not happy that I have to use a filter to correct something Sony failed to even mention initially but I am happy that despite it's drawbacks, I now have a solution to create videos that I want, looking how i want (even if it means an extra click or too in FCP to re-white balance).

Anthony McErlean
March 29th, 2009, 04:43 PM
Thanks Daniel, well, its good to know its not as bad as i first thought and if a slight zoom in from a wide cures it, thats good to know too. Glad the window thing isn't going to be a problem.

I received the filter from the supplier below on Saturday BTW

B+W 486 UV/IR MRC SH 77mm Ultraviolet / Infrared Cut Filter (http://www.fotosense.co.uk/b-w-486-uv-ir-mrc-sh-77mm-ultraviolet-infrared-cut-filter.html)

Thanks again.

Michael B. McGee
March 30th, 2009, 01:25 PM
i haven't read all the threads but i've been looking for the Schneider Tru-Cut 680. the one that ProVideo Coalition recommended for the EX cameras. Ryan at Schneider said i can buy it at Film Tools in Burbank, CA. i believe he told me the filters are on back order. i think about 3 weeks out from purchasing.

Ed Kukla
March 31st, 2009, 03:34 PM
Tiffen Filters also make an IR filter. Seems that this one is made differently than the Schnieder and that you don't get the green cast with W/A lenses. In addition, I think you don't need to put the filter on the outside, before any other filters. Downside is that they only make them in square and rectangular.

Anybody using a Tiffen Hot Mirror??

David C. Williams
March 31st, 2009, 04:28 PM
It's the Tiffen IR ND filter, hot mirrors do nothing for the EX, it already has one built in.

As far as I know you can't get them without the ND as well. They use a dye in proportion to the ND component to block far red, and you get no vignette as it's not a dichroic.

Ed Kukla
March 31st, 2009, 05:03 PM
David
I was on the phone today with Tiffen. You can get the filter WITHOUT ND. It is somewhat confusing as they mostly make the IR WITH ND for Red cameras.

David C. Williams
March 31st, 2009, 06:03 PM
If that's the filter with the dye only, no dichroic layers, that's great news because that is the perfect filter for the EX. Cuts all IR and no vignette. I think the process is branded ColorCore.

These http://www.tiffen.com/pr_infrared_filters.html

Leonard Levy
March 31st, 2009, 06:24 PM
Ed,
This sounds like very good news.

Do you have a name for that filter without ND.
Also did you talk with them about the value of making round filters for it Every EX-1 owner would buy one.
Usually they can make a round filter if you ask them, but it will cost.

Who did you talk to at Tiffen?

Ed Kukla
March 31st, 2009, 06:42 PM
Harold E. (Harry) Hofmann
Senior Technical & Customer Service Rep.
Tiffen Acquistion LLC
hhofmann@tiffen.com
631-273-2500 ext. 1405

Derek Reich
March 31st, 2009, 06:47 PM
David
I was on the phone today with Tiffen. You can get the filter WITHOUT ND. It is somewhat confusing as they mostly make the IR WITH ND for Red cameras.

Interesting. When I was on the phone to Tiffen, they told me this was not available. They also told me that any 4x4 IRND would have to be custom-cut and would take at least 4 weeks!

I also do not agree with the post which said hot mirrors do nothing for the EX. I recently took delivery of a Tru-Cut 680, and it seems to work quite nicely so far! I know the 750 does not work with the EX, but the 680/486 seems to do the trick. I have not even noticed the vignetting yet, so that does not seem to be a big issue.

I would be wary of the Tiffen without ND built in, as it seems using external ND's (including the ones in the camera) may very well affect the performance of the IR correcting capacity, since the amount of dye is based on the level of ND used. If no ND is needed, then it's probably okay.... but what do you do when using this filter outdoors?

David C. Williams
March 31st, 2009, 07:48 PM
Your correct, the 680 works, albeit with wide angle green vignette. I should have specified the 720 and 750. The built in EX hot mirror seems to work from @ 700nm onward.

The Tiffen IR ND range have the dye component balanced to not cut far red, but to reduce it in proportion to visible light. A normal ND 0.9 reduces visible light to 12.5%, but your still getting 100% of far red getting to the sensor. It then becomes predominant, and you get problems. The IR ND 0.9 dye reduces far red to the same proportion as visible light, to 12.5%

That's why I thought they didn't make them in that fashion as IR only. I hope is possible.

Derek Reich
March 31st, 2009, 10:04 PM
But what about the amount of dye being used in proportion to the level of ND being used? If a ColorCore filter is used without ND added, does this mean no external ND (camera NDs or other external NDs) can be used?
This is the way I understand it.... and why I decided against the Tiffen IRND filters. I simply wasn't going to pay $250-$300 for EACH level of ND I might need to have the proper amount of dye in proportion. I already have an expensive set of 4x4 ND filters. Personally, I'd rather save $$$ and deal with the possibility of some minor vignetting with the True-Cut 680 than have to buy a whole new set of NDs. I don't see how the ColorCore can be used successfully outdoors on a bright day.
If the ColorCore without ND can be used with various levels of external NDs, (including grad NDs) I'd be more interested...... anyone know if this is possible?

Piotr Wozniacki
April 1st, 2009, 01:56 AM
Derek,

Since you're the first one here to have the 680 filter, it'd benefit all of us if you posted some screen grabs showing its effectiveness. Before ordering, I for one would like to be sure it's as effective as its screw-on sibling, the 486.


Thanks in advance !

Bob Grant
April 1st, 2009, 06:10 AM
I've been following this thread for some time and am left with the feeling this issue will never be solved to everyones satisfaction.
I believe the 486 will be as good as it gets. The solution requires an extremely sharp cut at a specific wavelngth. This can not be achieved with a dye based filter. The 486 is multiple layers of a metallic coating which probably act like a stack of HiQ notch filters to effect a band cut filter.
I did a very crude test using two IR LEDs and our HC5 in nightshoot. One of the LEDs is around 1100nm and is invisible to the eye. The other would be around 900nm and is just visible. Both light up the HC5 nicely although the longer wavelength one is better. The 486 totally kills the shorter wavelength IR but not so much of the longer wavelength IR LED.
The IR filter in the HC5 (Nightshoot Off) kills both.
This was a very crude test but it certainly doesn't disprove my belief that the 486 is a very complex filter and that to achieve the same effect in any other way would be impossible. It is not a hot glass filter. We do have several extreme ND hot glass filters and from the outside they are like looking into a mirror, same as welding goggles. These filters are designed to stop heat (long wavelength IR) that could cook a sensor or eyeballs or at the very least cause green shifts in the image.

Piotr Wozniacki
April 1st, 2009, 06:21 AM
I'm not sure what you mean by that, Bob - is it that the 680 isn't going to work as effectively as the 486?

I did have the 486 but sold it, since I'm using the 35mm adaptor and need a 4x5.65" version for my matte box.

I now know it wasn't a good decision, but at least would like to see the effectiveness of the 680 before I pay again :)

Derek Reich
April 1st, 2009, 07:52 AM
I'm not sure what you mean by that, Bob - is it that the 680 isn't going to work as effectively as the 486?

I did have the 486 but sold it, since I'm using the 35mm adaptor and need a 4x5.65" version for my matte box.

I now know it wasn't a good decision, but at least would like to see the effectiveness of the 680 before I pay again :)

Piotr, unless I misunderstood Ryan at Schneider Optics, the Tru-Cut 680 is exactly the same filter as the 486. (correct me if I'm wrong, Ryan?) The only difference being the 486 is a screw-on filter and the 680 is a 4x4. (perhaps the same designation for a 4x5.65 if they make that size) Why it has a different name is confusing, but irrelevant to the performance of the filter.

I'll post some frame grabs when I have a chance to set up a decent test, but don't expect them to be any different from previous tests done by others with the 486/680.
I agree with Bob, this filter is as good as it gets at the moment. No filter currently is 'the' perfect filter, but the 486/680 is as close as we can come.

Piotr Wozniacki
April 1st, 2009, 08:58 AM
Michael,

Yes I have read the whole series of those articles.

Derek,

Yes I'm also assuming the 680 to be the rectangular equivalent of the 486; however I'd appreciate seeing some grabs of it in action. TIA!

Derek Reich
April 3rd, 2009, 10:43 AM
This from Art Adams:

Read the comments which follow the short cheat sheet. Interesting that Art doesn't list the 680/486 as a filter to use for the EX, also interesting that a couple of the comments mention that the Tiffen IRND is not available without the ND, but some people here have mentioned that it is. (for the record, I was told by Tiffen that it is not available without ND)

I'll post some grabs sometime in the next few days with the 680, looking forward to hearing from anyone if they are successful in obtaining a Tiffen without ND, and how it works?

Ed Kukla
April 3rd, 2009, 07:05 PM
I'm still trying to sort out the tiffen confusion. I think there are two kinds of tiffen filters. An IRND and a Hot Mirror (with or without ND). But I'm still not sure and can't get further answers back from them.
I think the Hot Mirror can be had without ND and should be a good solution but I can't yet confirm that.
And, they don't come in 77mm, only square or rectangle.

Bob Grant
April 4th, 2009, 08:17 AM
I think I've said this before on another thread on the same subject.

I believe there's a good chance that Art is solving a different problem to the one we're trying to address. If you add an external ND to any camera and if that ND does not also cut IR you can get more IR than visible light hitting the sensor and then you can have a problem. This seems to be one reason why the extreme ND filters commonly are hot glass. If you cut 10 stops of visible light and no IR it's pretty easy to see how a problem can arise. Of course that's an extreme example but I've even read of people having issues with a HVX 200 when they gelled windows and the gells did not cut IR.

So perhaps someone should invite Art to elaborate more on this issue before anyone jumps the gun and spends serious money on a filter that may not do the job or worse introduce more problems.

I also found this photo from another thread interesting:

http://www.dvinfo.net/conf/attachments/sony-xdcam-ex-cinealta/11528d1238348729-help-needed-ex3-owner-takes-apart-ex3-body-has-too-many-bits-left-over-dsc_3391.jpg

I see what appears to be a deep greenish filter in the optical path of the EX3, no doubt it's the same in the EX1.

Derek Reich
April 5th, 2009, 10:02 AM
Okay, so I promised to post some frame grabs with my Tru-Cut 680. I (hastily, as ususal) threw some black stuff on my bench and shot a couple of clips under different color temps, with and without ND, and with and without the 680.

This is not intended to be a test such as the comprehensive one conducted by Art Adams at the ProVideo Coalition. Just an everyday example of what one might expect using the 680. I have no other filters for IR with which to test anyway.

My conclusion is this. The 680 works perfectly for removing IR contamination (or, far red or whatever it is) with little side effects other than a slight color shift in the image (very slight) and a rather major green vignette at full wide. This was to be expected. Zoomed in at about 15mm on the lens, the vignette all but disappears. So the short answer to this problem (IMHO) is buy ONE filter, the Tru-Cut 680 and have it work in most of your shooting conditions, or buy SEVERAL Tiffen IRNDs (because they cannot be used with other NDs, and you have to buy a different filter for each level of ND you might need) and have them work in most of your shooting conditions. Neither is going to be a 100% solution.

Interesting to note that I put several different black items on the bench, with varying textures and structure. Only one was consistently and heavily affected in all color temps (the Skullcandy bag) and one fabric item was never affected (the gray and black shirt)
Other items were affected in different areas, like the borders on the Lectro cube cover or the media wallet. Smooth surfaces don't seem to be affected at all. (no surprise there) The reddish band on the speaker is indeed that color, that is not contamination.

So here you go, for your viewing pleasure: the highly professional stickies will indicate the status of that clip. I shot under incandescent (3400K) Fluorescent (4900K) and Daylight (HMI @ 6300K)
I did NOT re-balance when using the 680. (don't know if I should have done that or not)
The images have not been adjusted at all, they are straight frame grabs-
enjoy. There will be a second part to get the rest of the images in......