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-   -   Schneider Optics True-Cut 77mm waste of time (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/136128-schneider-optics-true-cut-77mm-waste-time.html)

Jay Gladwell October 19th, 2008 04:39 PM

Quote:

Originally Posted by Les Nagy (Post 953101)
I have been hoping that those who claim that they have the problem solved with the True-Cut filter would post images of their success. We really need to figure out the best solution for all EX owners.

Indeed! I'm right there with you, Les.

Barry J. Anwender October 19th, 2008 05:39 PM

Not Available Yet
 
Schneider has not responded to my e-mail request to order the 77mm True-Cut filter. There is no price or delivery information at this time. I'm pretty sure that Schneider is aware of the need and will let us know when they are ready to deliver.

Dave Morrison October 19th, 2008 05:54 PM

Quote:

Originally Posted by Jay Gladwell (Post 953068)
I've done a few preliminary tests of my own. Using my EX3, I see the problem only part of the time. Not all black on all fabrics come out reddish.

This being the case, is it a fabric issue, a dye issue, or is it a combination of the two?

I remember back in the day when I was a commercial photographer, we had issues getting certain colored fabrics in our photographs rendered accurately. Eastman Kodak developed a film especially designed to illuminate the problem. It's been so long ago, I can't remember the name of the film stock. In any case, it was a welcomed addition to the arsenal.

It's dejavu all over again.

You're SO right, Jay. My background is also in Commercial Photography and I remember that certain fabrics would "flouresce" (sp?) due to brighteners added to the fabric dyes. I think it was one of the Ektachromes that had the properties you mentioned but I can't remember the emulsion numbers anymore. That was many, many sheets of 4x5 ago! I also remember that certain "crossover" colors would cause problems as well. For instance, getting certain shades of teal would be problematic. The transition between blue and green could be a nightmare. The first test shots I did with my EX1 was under tungsten light of a guy talking. He was wearing a black baseball cap and it photographed as VERY brown in color. I'm following this thread with great interest as well.

Serena Steuart October 19th, 2008 06:52 PM

Quote:

Originally Posted by Ryan Avery (Post 951999)
Les,

The True-Cut IR 750 requires that it is the first filter the light hits. This because it reflects the IR light. If there is another filter in front of it, it will not work. Also if there is another UV filter in the series it will diminish the effects.

This is often stated, so must be so. But why is it so? If the filter is placed downstream of other optical elements that will reflect IR reflected by the filter, how is that second reflection altered in such a way that it gets passed by the IR cut filter? If the filter reflects 100% of IR in the specified bandwidth, then any reflected IR in the bandwidth will get reflected again (and not passed). If 90% gets reflected, then on the second go 90% of 10% gets bounced back again, and so on. How do other filters change the bandwidth of the IR component prior to meeting the IR cut filter, to make it less effective? True a filter does not have a square cut-off characteristic, but how does that affect the argument?

Les Nagy October 19th, 2008 07:16 PM

Serena

The filter works by using interference principles of multilayers to reflect the desired wavelengths instead of letting them pass on. The layers are spaced properly for the wavelengths desired. Light entering the filter straight in are properly affected. Light entering from an angle see the spacing of the layers differently because of the angle and therefore do no interfere properly.

When the filter is the first optical element the reflected light disappears harmlessly into never never land. If the filter is behind other optical elements it is possible for those elements to scatter and reflect the light back towards the filter in such a way that they enter the filter at an angle and get through. Lens designs this kind of complexity have to be carefully designed to prevent such backscattering in the first place and adding a mirror arbitrarily in optical path is almost a certain formula for problems. These problems could be flare, ghosting, multiple hot spots, etc. That is not to say that it isn't possible for something added in the optical path to work but the chances are it won't fix the IR problem without causing another or even worse multiple problems.

Dean Harrington October 19th, 2008 07:32 PM

IR filter ...
 
Quote:

Originally Posted by Les Nagy (Post 953170)
Serena

The filter works by using interference principles of multilayers to reflect the desired wavelengths instead of letting them pass on. The layers are spaced properly for the wavelengths desired. Light entering the filter straight in are properly affected. Light entering from an angle see the spacing of the layers differently because of the angle and therefore do no interfere properly.

When the filter is the first optical element the reflected light disappears harmlessly into never never land. If the filter is behind other optical elements it is possible for those elements to scatter and reflect the light back towards the filter in such a way that they enter the filter at an angle and get through. Lens designs this kind of complexity have to be carefully designed to prevent such backscattering in the first place and adding a mirror arbitrarily in optical path is almost a certain formula for problems. These problems could be flare, ghosting, multiple hot spots, etc. That is not to say that it isn't possible for something added in the optical path to work but the chances are it won't fix the IR problem without causing another or even worse multiple problems.

This effectively means that one would have to get 2 IR filters if working with a mattebox and other filters behind that and one to go directly on the lens when using the fujinon lens shooting with the EX3! I wonder if Schneider optics would bundle both filters for a reduced price? The 4X5.5 is $400 and the 77 mm is around $300. That's pretty pricey for just this filter!!!

Alister Chapman October 20th, 2008 02:45 AM

anyone tried using a tungsten to daylight colour correction filter and then shooting with a daylight white balance. This would allow the use of a stronger red reduction via the filter although it would push up the cameras red sensitivity.

Ryan Avery October 27th, 2008 10:40 AM

Quote:

Originally Posted by Barry J. Anwender (Post 953134)
Schneider has not responded to my e-mail request to order the 77mm True-Cut filter. There is no price or delivery information at this time. I'm pretty sure that Schneider is aware of the need and will let us know when they are ready to deliver.

Barry and all,

We taken considerations regarding the EX-3 and the True-Cut IR 750 into account. Our engineers have worked to deduce the problem Les experienced. We value our users feedback and are always looking for ways to exceed your expectations with regard to quality and performance for which we are known. If you already own a True-Cut IR 750 and have not had any problems, then you are ok.

You can buy this filter at any of our authorized DV Info sponsors.

Reference the description and part number:

77mm True-Cut IR 750
68-121077
List Price: $250.00

Ryan Avery
Schneider Optics

Ryan Avery October 27th, 2008 10:42 AM

Quote:

Originally Posted by Alister Chapman (Post 953261)
anyone tried using a tungsten to daylight colour correction filter and then shooting with a daylight white balance. This would allow the use of a stronger red reduction via the filter although it would push up the cameras red sensitivity.

We have developed a 1/2 strength blue color correction filter. It seems to work well with the RED camera for which we developed it. Our Sapphire Blue filter was being used on productions but it was slightly too strong so we reformulated it with some changes particular to this application.

Ryan Avery
Schneider Optics

Michael Maier October 28th, 2008 06:20 AM

Ryan, how do you feel the 489 works for IR cut?

Ryan Avery November 3rd, 2008 11:45 AM

Quote:

Originally Posted by Michael Maier (Post 956555)
Ryan, how do you feel the 489 works for IR cut?

The 489 was not designed with the cut rates necessary for the EX1/EX3. It will create a blue cast on wider angle incidences of light. This filter was designed mostly for industrial applications.

I had one user buy it without consulting anyone and it wound up not working for his EX1.

We are looking at the IR issues presented by the EX1/EX3. The True-Cut 750 IR seems to work in some cases but not others. Most users we have sold this filter to have not complained and use it extensively. As the test pictures show here in this thread, there are some fabrics that the IR light is more of an issue. More to follow soon.

Ryan Avery
Schneider Optics

Jay Gladwell February 9th, 2009 10:07 AM

To Ryan Avery
 
Quote:

Originally Posted by Ryan Avery (Post 959088)
The 489 was not designed with the cut rates necessary for the EX1/EX3. It will create a blue cast on wider angle incidences of light. This filter was designed mostly for industrial applications.

I had one user buy it without consulting anyone and it wound up not working for his EX1.

We are looking at the IR issues presented by the EX1/EX3. The True-Cut 750 IR seems to work in some cases but not others. Most users we have sold this filter to have not complained and use it extensively. As the test pictures show here in this thread, there are some fabrics that the IR light is more of an issue. More to follow soon.

Hi, Ryan! After ninety days, I can't help but wonder if we're any closer to a resolution with this IR problem on the EX cameras?

Thanks!

Brian Cassar February 9th, 2009 12:44 PM

Ryan I too am anxious to know if there were any developments. I've just bought the 486 and I feel that I've wasted my money. It does correct the IR contamination but produces the horrible green vignetting which is not that easy to correct in post (or at least it's time consuming). If to correct one problem another one is induced than it is a scenario of "out of the frying pan into the fire..."!

I'm really dreaming of that elusive IR filter that settles once and for all this headache.

Matt San February 9th, 2009 04:51 PM

we all are!! just there doesnt seem to be one right now!

Dean Harrington February 10th, 2009 06:25 PM

If ...
 
Quote:

Originally Posted by Jay Gladwell (Post 1009139)
Hi, Ryan! After ninety days, I can't help but wonder if we're any closer to a resolution with this IR problem on the EX cameras?

Thanks!

If an IR filter does not do the trick, I wonder if sony can do an internal software adjustment to cut off the IR levels in the EX1/3? This may be an option, no?


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