Red problem !

[Michael Maier]

I'm having some weird problems with the EX1. I have to shoot in a room where the walls are a deep dark red. It's a pretty low key shot so there's lots of shadows. Then something weird happens. One of the actresses is blonde and her hair is looking deep red, almost a wine color in the camera. If the whole room is bright it looks almost normal, but at lower light levels she looks like a red head out of a L'oreal commercial! Other actors with black or brown hair look normal. I tried everything apart from playing with the color matrix. Any ideas of how to correct for that? Thanks.

[Zenes Petrusin]

I have some problem with colours, but not only red, black is btw. brown etc. WB is right.

I try every profiles posted here, Winnie, Bill (TC1, TC2)... etc. but dont help for best result. Still some colour is miss, specialy black is not black. And for second, WB in EX1 isnt so good, becous is horrible slow to finding right White Balance. I try change speed, but still slow or maybe dont change nothing automaticaly, must do WB manual for right temperature. I never have problem like this, my small HDV Sony HC3 produce outstanding color, and never problem with slow WB and of course my older PD170 some never has problems like this.

I dont understand why EX1 has problem with colour and slow WB. I only waiting for new firmware if helps or make call to my dealer, but i think he cant help me about this, all EX1 has similar problem.

[Benjamin Eckstein]

That is interesting what you say about the black colors. I find this to be true on the EX-1 and I have noticed it on other cameras that certain fabrics (like black fleece) will appear reddish on the camera. It must have to do with the reflectivity of those fabrics. A black cotton t-shirt will look black. Black shadows will be black, but fleece type fabrics look red. More of an interesting point then a problem, because I have definitely seen it on other cams so it must be some light emission thing.

[Sean Donnelly]

Is it possible for you to post a still? It could be a software problem in the camera, where the color matrix is picking up on the small amount of the darker red being reflected into her hair from the walls. This would explain why other actors are unaffected, and why it looks almost normal at higher exposures. The F23 had a problem early on where the processing was misinterpreting a specific shade of blue-gray.

-Sean

[Zenes Petrusin]

My still
first is from HC3, colour OK, WB OK
second starts from EX1, pp off, bag has two colour
third, pp on, TC1 profile from Bill (Thank you Bill), black on bag is i dont know why in two colour too..
I have some problem with TC2 profile from Bill.

PD170 dont see two colour on this bag too, my eyes see some as HC3 and PD170 :D

[Giroud Francois]

it is a well known problem from photographer since a long time.
It is called infrared contamination
you can use an hot mirror to get rid of the infrared
http://www.tiffen.com/results.html?s...ormat=Screw-In
they are usually pretty expensive while a simple glass can do the job as well.

http://lloydchambers.com/diglloyd/fr...amination.html

http://joi.ito.com/archives/2007/04/...ckr_group.html

[Brian Carrell]

I have a 77mm B+W 486 IR Cut (blocking) filter, I can't remember who else makes them (at the time I was looking for this solution, all I could find in the States, was this filter by B+W, which I got from B&H)

http://www.bhphotovideo.com/c/produc...tal_UV_IR.html

I'm wondering if this is how this particular sensor reacts to differing wavelengths. As I did not encounter this with my Canon XHA1 or older Sony DV camcorders.

Outdoor use in San Diego, I can't see much noticeable difference. Outdoor use when I was up north closer to the Arctic in Canada, I really could see a difference, especially in Reds, Greens and Blacks. I manually white balanced and included a white/gray reference in the beginning of each shot, so I know the balance was correct. I also noticed a difference in this situation with my Canon HV20 as well as the PMW-EX1.

Then indoors under various types of indoor lighting I started noticing this effect as well by using and not using the filter, which varied under different types of lighting. Again this effect is stronger than with the Canon XHAI in the same setup.

I stumbled on a few German sites that discussed this type of filter and there were actually stronger ones mentioned, that I have been unable to find here, one was darker in color and reduced light by about 2-stops.

Maybe one of our more tech savvy engineer memebers can shed some more light on this. But this filter does help a lot with this camera's sensor, I'd still like to find even a stronger one. Of course I haven't shot in a red room or set yet.

[Swen Goebbels]

I have the same problem. A black skirt was looking brown.... in the same picture a black tire of a car was still black. Also we did some still pictures with a Eos5d and the skirt and the tires were shown in correct (black) color! Maybe it's possible that this happen more with clothes than with other things. Really strange.

I have to drive now to a shooting we will do tomorrow and I'm thinking about to use my old PD170 (black is allways black!) and not the new Ex1 for this, because I'm affraid to have wrong colors on the picture.

[Valeriu Campan]

Leica has experienced a similar issue with purple contamination of the black pretty well documented around the web. They fixed after a while a very vocal outcry from photographers.
This is just one of the articles published:
http://www.outbackphoto.com/reviews/...asHoepker.html

[Giroud Francois]

take care when you go in the shop to buy the filter.
if you ask for an IR filter, they could give you a filter that let pass only IR.
That is the reversal of what you need. You need a hot mirror that blocks the IR. this is pretty confusing, since in photography, an UV filter blocks the UV and an IR filter allows to take pictures with IR.
An hot mirror filter that rejects IR must be totally transparent. if it is more or less dark it is cold mirror that reject visible light and let pass IR.

[Zenes Petrusin]

Has sony reason why not install IR Cut-Off/HOT MIRROR filter into EX1 like in other products?

If i read correctly all colour problem is EX1 dont have this filter like other camcorders.

[Eric Pascarelli]

All this makes me want to experiment with an IR pass filter to see if the EX1 does interesting thing with IR photography.

[Sean Donnelly]

EVERY camera is made with an IR low pass filter installed. You wouldn't have an image (at least a worthwhile one) without it. The issue of IR contamination seems to be happening however with every CMOS camera I've tested, particularly the RED ONE. This is an issue mostly when shooting with high levels of ND (1.5-1.8 or so) which block visible light, but not IR, so it shifts the ratio of visible-IR and allows you to see it. Zenes, what kind of light source were these taken under? I'm not totally convinced this is IR contamination, since IR usually makes a bluish-magenta haze over dark subjects, not the green-magenta split tone you've illustrated here.

-Sean

[Giroud Francois]

it is possible that we got a mixed effect between the IR contamination and the electronic trying to keep balance with the WB.
that would explain that by trying to fight the purple/magenta , the camera goes to the green side.
A simple test with a hot mirror would give the answer, or taking the same picture with an halogen 3200 (plenty of IR) or an HMI 5000K.
Anyway that strange that such problem still occurs on new model, since it is known for a long time in photography. Or engineers for sensor in video are not the same as in photography ?

[Zenes Petrusin]

Hi Sean,

every CMOS camera dont has problem like EX1, HC3 has CMOS too, but dont see any problem like in EX. I think yes, all cameras has IR cut off implemented, but something dont good and i dont know if this corrected in new firmware or must buy hot mirror filter but is expensive and hard to find shop to have this for test in shop.