Red problem !

[Piotr Wozniacki]

UPDATE

This is something that might sound good for those considering spending their bucks on the 486 IR cut filter, but it's certainly not good news to myself...

Upon repeated and careful re-inspection of my footage with the filter, I must regretfully admit the effect in the corners is due to some definite accumulation of the 486 filter's inherent, greenish hue, AND my camera's vignetting (ouch, arghh - whatever your Anglo-Saxon onomatopoeia is for the sounds I have been emitting for some time).

Without the filter, I only managed to spot some minor, upper left of right corner vignetting at extremely fast panning and OIS on; who cares? - I thought.

But it has now been amplified by the green cast from the 486 filter, and it seems I DO have the vignetting problem, after all!

It'd interesting to know (although I sincerely doubt that Sony will ever reveal this): was the tight tolerances, leading to the potential vignetting, the reason to not implement proper IR filtering in the EX1, in the first place? Could the two be somehow related?

And, a logical question that follows: has it been rectified in the EX3?

Here is a frame from the same material I posted before, but when my camera happened to be more static (I shot it all hand-held); as you can see there still is SOME green cast along the very left/right edges, but NOT specifically the corners...

[Piotr Wozniacki]

Could someone with the double-threaded version of the 486 filter post some screen grabs, preferably with and w/o Letus? I must make up my mind whether it's worthwhile to spend my cash on another one, before an important event where I'll be using my Lex... Thanks!

[Mike Stevens]

Piotr:

A double threaded version is hard to find - in fact of the B+W I don't think it exists, so this is what I did. I have a 77 to 100 step-up ring with a 95mm thread inside, to which I clamp my Cavision matte box (see my threads on that for interest). Inside this step-up ring I have a 95 to 77 step-down ring that holds the 77mm IR/UV filter on the inside so that the IR/UV filter is in fact in "backwards." This allows the use of the 77mm filter behind a matte box and is a lot cheaper than using the 100mm filter which is about $500 or wasteing a matte box slot. This arrangement works fine and there is no vignetting at any focal length by reversing the filter so it is as close as possible to the camera.

Mike

[Sean Donnelly]

I actually have the double threaded version of the 486. It is a very difficult item to find, and I had to pay top dollar for it. I spoke to someone who is closely connected to schneider and it seems they were taken by surprise with the increased deman, so they need to make more. If I had a letus, I'd be happy to post some stills...

-Sean

[Graeme Fullick]

I am still not sure if I will buy the IR cut filter. I find the green cast on Piotr's shot above far worse than an incorrect black. At least the incorrect black is not anobvious visual flaw to most observers. They would never know that the black was not slightly brown, but they could certainly see the obvious green cast at the edges. I agree it could be a much greater problem when trying to match 2 cameras - where one shows black and the other brownish black - but this is less of a problem to me.

I still might buy the IR cut filter - to give me the greatest number of options - but that green cast worries me enormously. I doubt that I can fix it in post satisfactorially so that I would be happy.

[Mike Stevens]

Originally Posted by Graeme Fullick

I am still not sure if I will buy the IR cut filter. I find the green cast on Piotr's shot above far worse than an incorrect black. At least the incorrect black is not anobvious visual flaw to most observers. They would never know that the black was not slightly brown, but they could certainly see the obvious green cast at the edges. I agree it could be a much greater problem when trying to match 2 cameras - where one shows black and the other brownish black - but this is less of a problem to me.

I still might buy the IR cut filter - to give me the greatest number of options - but that green cast worries me enormously. I doubt that I can fix it in post satisfactorially that I would be happy.

You must recolor balance to make a compensation for the 486. One reason the EX1 is such a good camera ity can do this - that what all thoses r-b, G-r, deals are in the Matrix settings. See my post re Bill's color sorrection and the 486 and do this first

[Graeme Fullick]

Sean,

Is this the filter you have?

[Sean Donnelly]

The filter I have is the B+W 486 77E. It has threads on both sides.

I spoke to someone at sony today, who said my complaint has been filed with the engineers in Japan, and they hope to hear something soon.

[Piotr Wozniacki]

Does anyone have experience with the 489 filter, which is absorbing IR rather than reflect it?

[Mike Stevens]

Originally Posted by Piotr Wozniacki

Does anyone have experience with the 489 filter, which is absorbing IR rather than reflect it?

Piotr:

This is an interesting question. These two filters may have different effect on the visible red muting. I went with the 486 following what Bob Grant did. I'm not sure if I will still use it as a general filter when not needed.

Anyway, I think both filters will need Bill Raven's color adjustment being redone but where is Bill? I have not seen him post for a while.

[Michael Maier]

Originally Posted by Piotr Wozniacki

Does anyone have experience with the 489 filter, which is absorbing IR rather than reflect it?

As I said, I'm using the 489 with great results. The person I talked to at Schneider told me it was the right one if I wanted to use it between a 35mm adapter and the camera since it absorbs the IR rather than bouncing it around.

[Leonard Levy]

Are any of you guys getting the green vignetting that Piotr reported, with either the 486 or 489? What are the pros & cons of those 2 filters by the way?

[Piotr Wozniacki]

Originally Posted by Michael Maier

As I said, I'm using the 489 with great results. The person I talked to at Schneider told me it was the right one if I wanted to use it between a 35mm adapter and the camera since it absorbs the IR rather than bouncing it around.

As I am a LEX user, I'm interested in the 489 - I understand it has two threads, but can it fit under the original lens hood, like the two-threaded version of the 486 is reported to?

[Piotr Wozniacki]

OK - again, I can sell my 486 SLIM (cannot use it with LEX), but which one to buy instead: the regular (double-threaded) 486, or a 489?

Is there a confirmed opinion about either being better with LEX, while being also able to put the standard lens hood on?

The filter factor of the 489 is 1.2 as compared to the 486's 1.0; but should absorbing IR result in extremities being free from the green cast, I guess it'd be worth it!

[Ryan Avery]

To all,

So I've watched all of the posts regarding this and I would like to speak on a few issues.

1) The B+W 486 filter is a very effective filter for the blocking of all IR light at about 670-700nm. This is extremely effective at preventing "IR Bleed" into the black tones. To date, most people using this filter have only used it because they are experiencing IR Bleed on their black tones mostly in high contrast situations (concerts being a very popular application). Your video camera already has an IR Cut filter infront of the CCD or CMOS that is generally very effective however not perfect. As the tests show, this is not a one size fits all type of application.

2) The filter is sensitive to the angle of incidence of the light. If the angle of view on your lens exceeds 60 degrees, then you might experience color shifts and chromatic abberations. This is a result of the design of the filter and unavoidable. Due to the proximity of the built-in existing IR CUT filter to the CCD or CMOS Chip, this problem is largely eliminated on the stock lens.

3) In our quest to solve the issue with RED users (whose internal IR CUT filter is woefully inadequate), we have had to develop this filter to meet the specific needs of video users. Hence, we have had to redesign the filter. The existing B+W 486 filter exists with an IR CUT on one side of the filter and a UV filter on the back. This is to solve UV sensitivities that are not present on video cameras. Therefore, we have redesigned the filter with the IR CUT on one side and an anti-reflective coating on the other side. This reduces internal reflections caused by the filter.

4) Use of the new Schneider filter (not 486, official marketed name tbd) must be done with the IR CUT side facing out toward the subject. The existing 486 filter is only made up to 77mm and there for the mounting direction should not be an issue. The new Schneider filter will only be made in square and 4x5.65 sizes to meet the demands of the largest user group of RED owners. The B+W filter is still an excellent application for most other situations as has been proven in the past.

5) Filters that combine ND and IR CUT in the same filter have been proven to be inadequate at completely eliminating the IR light at useful nanometer ranges. We are looking at development of this type of filter but the engineering challenges of doing it right is something that we need time to develop. My personal feeling is that this is not a good solution because it only solves your IR Bleed issues for one filter, not your entire set of filters that you paid a lot of money to acquire.

Schneider Optics will likely have this new version of the filter available in the next few weeks. Please contact your favorite dealer (hopefully DVInfo sponsors) to get on the growing waiting list for this filter.

Ryan Avery
Schneider Optics