DV Info Net - Filter for IR contamination

DV Info Net (https://www.dvinfo.net/forum/)

- Sony XDCAM EX Pro Handhelds (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/)

- - Filter for IR contamination (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/143010-filter-ir-contamination.html)

Quote:

Originally Posted by Olof Ekbergh (Post 1166659)

Here is a frame grab from FCP in PSD with info tool.

We shot him in suit as well.

Go figure I don't see any overly red. Maybe it is just my PP. I am using a UV filter but that is it.

It could be that the materials you're shooting don't have the problem. I've only noticed the problem mostly on synthetics and blends.

Quote:

Originally Posted by Ben Chiu (Post 1166663)

It could be that the materials you're shooting don't have the problem. I've only noticed the problem mostly on synthetics and blends.

My understanding, not having seen it first-hand due to the fact that I've had the 486 filter on since day-one, is that it is related to the material of the black object in question, not the color black itself. Something about the way the material reflects the IR spectrum differently that the camera is sensitive to and ends up picking up and recording - it's over my head, but that's what I've read in this post and a couple of others.

Quote:

Originally Posted by Ben Chiu (Post 1166663)

It could be that the materials you're shooting don't have the problem. I've only noticed the problem mostly on synthetics and blends.

Here's a variety of fabrics. The neutral colored pic (IMG_0039.jpg, right hand side) was shot with a CANON SLR, the other one with my EX1. It shows drastically, that certain fabrics reflect a huge amount of IR-light.

I always use a UV-filter, I do need another one.

Rgds, Eva

Quote:

Originally Posted by Brian Cassar (Post 1166570)

Hi Max, I use the Z90 primarily on my EX3. The Z90 is surprisingly very light in weight and cannot see any problem in putting it on the EX1 front accessory shoe. I have the Bebob EX3 V-mount adaptor togeher with the VF Gadget shoulder mount. The Z90 draws up to 30 watts in full power and so you need a powerful battery to be able to sustain such power. I use a BlueShape 210 WHr battery and power both the camera and light. Apart from giving me many hours of filming, this battery also mkes the camera back heavy.

Going on to the EX1, I do have an EX1 as a spare camera in case the EX3 decides to pack in. I have bought another VF gadget plate and found that it can be used with the EX1 and will turn the camera from a hand held to a shoulder mounted camera. I have bought a Hawk Woods V-mount adaptor and has attached this to the Vf Gadget so that I can power both the EX1 and the Zylight with a V-mount battery (the same that I use for the EX3). I have never used the EX1 with the Z90 on board but as I said I cannot see any problem in this.

Please note that for stability purposes I have attached the Z90 to the accessory shoe with the help of an accessory that has a hot shoe end at one end and a screw that fits the Zylight at the other end. By this way the Zylight is closer to the camera body and hence more stable. I did not buy the articulated arm which would make the rig rather unstable. I use my EX3 mainly for shoulder mounted wedding filming (no tripods) and hence stability and compactness is of prime importance. The Pag light was surprisingly more protruding than the low profile Zylight!

True with no arm the rig will be more stable. We have a the mount that attaches the light to the shoe as you say, but I'm not tall so the nose shadow and possible slight underlighting a straight on angle causes is not a good path for me, aside from other shadows from mattebox, shotgun and lens attachments in a macro shot. The arm opens up angles for me. We have both the z50 and z90. I'm also interested to what your converted EX1 looks like!

IR .. here is a bad one.

GRAY SUIT TURNS BROWN. Major convention footage shown here ... mixed lighting with tungsten and 5600 sources. Daylight preset balance (also tried setting WB with same result) Luckily client speced the EX-3... what would I do if I pitched this camera and this happened?

I have shot for two days with no color shifts before this one. I am now wondering if certain fabrics react differently (cotton, wool, etc.). I was thinking that this problem was infrequent and overblown-- not any more. I will review all 20 pages of this thread, but I think if Sony does not offer a "patch" that class action litigation may be in order. In 25 years shooting broadcast video I have never seen anything this extreme. Yikes! The old Ikegami never looked like this. I guess I have 486 filter in my future.

I did this short test after I got my 486 filter. All the black fabrics turned brown except for the fabric on the seat itself:

IR contamination of Sony EX1 on Vimeo

dave

Quote:

Originally Posted by Dave Morrison (Post 1172642)

I did this short test after I got my 486 filter. All the black fabrics turned brown except for the fabric on the seat itself:

IR contamination of Sony EX1 on Vimeo

dave

Very nice test, Dave, thanks. Makes me feel better for my 486 purchase, despite the fact that the camera itself still has a pretty big issue there. Also shows me that you can't necessarily predict the type of light that will cause the problem... ugh

I followed that test a day later when I took the tripod bag outside in the sun and it turned brown in daylight as well. The 486 cleared it up okay, but you still have to adjust out that slight green tint, too.

"It's a feature, not a bug!"

Quote:

Originally Posted by Dave Morrison (Post 1172655)

Thanks for doing that little live demo. As I always suspected I detect a green tint over the entire picture with the 486. This is easier to see here than in frame grabs where the eye tends to adjust quickly to compensate for such slight tints. I do not see the blacks coming back but the entire picture turning green and distorting all colors in the picture. That's just how it looks to my eyes. Certainly, the brown blacks are gone. I'm suspecting the Tiffen will be similar.

Quote:

Originally Posted by George Griswold (Post 1171803)

I just looked at your clip. Looks pretty bad if suit was gray.

But look at the skin tone.

I took a still from your video and analyzed it in PSD with eyedropper, 1st image.

And then I used Eyedropper points to white balance by numbers only in the Highlights, second image.

You will notice the skin tones are also much better when numbers balance.

It is really hard to mix Tungsten and Daylight, in a situation where you don't control lighting this is almost impossible. Where do you put white card. I sometimes find as little as 3' makes a huge difference.

The only way to fix this stuff is in post Color or similar.

I just played with image in PSD, the numbers are interesting though. I used technique I use for stills scans or digital photos.

Pick 3 points and adjust color balance until numbers check out even.

In this shot I would probably also desaturate a bit. Some of it is also a little blown out. I know you could make it look really good in Color.

Look at the adjustment numbers they give you a good indication of where problems lie. Mostly not much blue.

olaf
you got the suit grey but I liked the flesh tones of the brown jacket shot MUCH better

Quote:

Originally Posted by Ed Kukla (Post 1173461)

olaf
you got the suit grey but I liked the flesh tones of the brown jacket shot MUCH better

I was not trying to make the shot look great I was just applying white balance.

I think the skin tone in the corrected shot is truer (maybe not nicer), when you wear a blue shirt. The shadow under your chin will be bluish. And the backdrop was blue, this would produce a bit of blue spill around the edges of face, and hands.

If you really color corrected this shot you could apply secondaries to any number of different elements or colors to achieve any "look" you want even warm skin tones and true blacks and grays.

The main point I was making is you cant judge a shot that has improper white balance, and blame it on your camera. You can it fix in post, when it is not possible to set properly when shooting (always the best option).