Just received my EX1. Same problem with black fabrics. I'm going to borrow an IR cut filter tomorrow to see if it makes a difference. If it does, I think sony owes us one. Looks like I need to send it in for vignetting as well...

-Sean

It's not just an ex1 thing. I remember shooting a wedding in India a year ago with a V1. I looked at a sari -- noted the color -- looked into the lcd -- and it was another color completely. Still good quality, but a different color. I think pure blue turned to magenta, or vice versa.

I suspect that the reason low cost cmos cameras don't show this effect is because they don't have a color-splitter prism. They are single chip cameras with a Bayer filter.

My guess -- the prism/color filter/cmos block responds differentially to the IR that does pass through whatever IR filter the lens has.

I wonder if the F23 processing was "fixed" because it had an error -- or it was "modified" to compensate for the excess red. For example, after a white balance and black balance the camera knows how much total visible light is coming from the scene. When the DSP finds areas that have more red than should be possible (hot areas) -- it assumes the energy is IR and corrects.

I really doubt Sony is going to add this type of correction to the ex1 given it's price-point.

Well,
What do guys think about this:
http://www.bhphotovideo.com/c/produc...tal_UV_IR.html

Should it do the trick?

I'll let you know, I just ordered the 'thin' version that is in stock.

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

Also, I too heard the um 'rumor' tiffen will have a nd with ir reflection at NAB to put in your mattebox.

Also, NOTE - tiffen's hot glass reflects and thus has to be the out filter, whereas the 486 obsorbs IR and UV and can be screwed on and be the inner filter - ie - replace your lense protection filter.

I'm quite curious to hear about this, because I'm buying in a short time, and if I can run a nice Red Filter over top of this lens and shoot some B&W, I could quite possibly pull some B&W IR Video recording for artsy stuff :)

Dave

I tested this with the Ex1 and the IR remote controll of my TV. With my eyes I can't see the light. On the Ex1 LCD I see a RED light (not very bright).

Now I tried the same with my PD170. And there the light was GREEN (and much brighter. You could really "dazzle" the camcorder which was not nice for the picture-EX1 doesn't have this "Problem").

So my question: Why is the same light shown RED on Ex1 and GREEN on PD-170. Does the PD170 has an inside filter or similar and the Ex1 not?

Sure the PD170 is CCD and not a CMOS. So I also tested to make a picture of the light with my Eos5d: The light was RED (same as Ex1).
However, my Eos don't have that color problem and allways shows balck as black.

This is nice because that way you can have the filter on the camera lens when using 35mm adapters and not on the front lens, which would mean having to screw it on and off every time you changed lens. But is absorption as effective as reflection? Seems to me a filter could reflect more IR than it could absorb. Then again I have no idea. When are you getting yours?

I'm going to try and find one to test with today. I believe the reflective filters are more effective, however I hope the 486 filter is enough to counteract this problem, since I really don't like the idea of having to put it on the outside of a 35 adapter. Also I'm not sure about the hot mirrors, but the 486 has no required stop compensation.

-Sean

Greg, let us know if this filter fits well and does not obstuct the hood.
Also, let us know if you see an improvement.

Just checked the B+W 486 description again on BH and it actually reflects the IR instead of absorb it. It seems to be the same as the Tiffen Hot Mirror. With a little more research I found their 489 filter which seems to be the one that absorbs rather than reflect the IR. So the B+W 489 seems to be the ticket. I'm just wondering if using NDs and Polarizers in front of it will bring the problem back.

Yes Michael, but 489 has Filter Factor 1.2 and 486 factor 1 . 489 maybe change color more, becouse has some colour smell, so not be realy transparent. If you want use polarizer you can attache 486 on polarizer. But i dont know if for this realy help IR cut-off/hot mirror filter, this is for me only theory. Maybe sony do some conclusion about this, is for me this IR contamination if really is, problem.

Well, the 486 would need to be used in front of the other filters because it needs to reflect the IR. The 489 can be used under other filters because it absorbs the IR. This seems more useful if you are using a 35mm adapter for example. So the 489 can go on the camera lens instead of on the Nikon or PL lens in front. Also, if you use a matte box the 486 screw in is no good.

Well, "interference" between layers on the 486 'sounds' like its not reflecting it like a mirror either. Here's what is says:

"This B&W 77mm 486 Digital UV/IR Blocking Slim Glass Filter has a completely colorless glass carrier coated with a number of extremely thin, partially reflecting layers with precisely computed thicknesses, similar to MC coating (multi-coating).

The B&W Filter 486 does not block by means of absorption, but by interference of the unwanted UV and IR radiation that is repeatedly reflected between these layers affecting the wavelengths on both sides of the visible spectrum with a steep cut-off.

B&W slim filters are for wide-angle lenses and are 3mm thick. They do not have a front thread.

Key Features

• Used mainly on digital and video cameras with CCD sensors without an integrated IR protection filter, because the IR sensitivity of the CCD sensor would otherwise cause color changes and unsharpness.
• That unsharpness results from the chromatic aberration of the lenses that are only corrected for visible light.
• In the visible range, the transmission curve is very high and straight."

---
If it does not work, I will have to get tiffen Hot Glass 4x4 and place it in front of my mattebox - since I use polas and grads all the time shooting high contrast sunsets.

QUESTION?!

If RED light like a sunset gives off more IR, and creates more distortion...
Then, wouldn't a BLUER setting, or cooling filter reduce IR - and then in post one could warm it up with less IR???

PS - I get my filter tomorrow. I will try to shoot some tests this weekend and post ASAP.

Thanks Greg. I'm looking forward to hearing and possibly viewing your findings.

That might "fix" it but I'm pretty sure that would make you have other problems such as areas that aren't suffering from this shift because there is adequate light reflecting off of some of the subject matter in your shot. So even though those few spots that are giving you problems, are corrected, I think you'd see other problems creep in to areas that are being represented accurately.

Dave

Guys,

I am a Chemist by trade and work with spectroscopic equipment all the time. We use interference filters quite often. Essentially it works by setting up the filter so the light that you do not want transmitted is used to cancel itself out. Without going into the physics of it the fancy optics generate interference patterns in the IR (and in this case UV) light waves that are 180 degrees out of phase with the incoming radiation effectively blocking its transmittance into the lens. The fact that it is a sharp cut filter means that it will not interfere with the visible wavelengths - therefore you should see not interference at all in the visible range if the filter is well built - and with a B&W that is likely. The absorptive filters use chemical compounds embedded in the glass that absorb specific wavelengths of IR radiation. Of course this means that they may get a bit warm if there is excessive IR (the energy has to go somewhere) - but this is not a likely scenario with a camera filter where we are talking about small amounts.

Bottom line is that it is likely that the filter will work well - but we will see shortly. The proof is in the testing!

IR 486 Filter Works!
 

Just got my filter today from B&H. So far, it appears to work great at getting rid of the RED cast when filming certain black fabrics in lower light situations.

I will post some before and after shots when I get a chance.

Paul

That's great news Paul. Just for fun I put a piece of Rosco heat shield in front of the lens today, and it did make a small difference. Certainly not optically clear, but it did help to prove that it is an IR problem.

-Sean

Paul that are really great news! For me this was the main problem of my Ex1.

What do you guys think? Have we all to buy this filter for 200$ or will Sony offer us an "upgrade"? Why did Sony not just build such a filter directly into the camcorder... for them this will maybe make the cam 40$ more expensive, but that's much better than angry customers and wrong colors.

Here in Germany some TV stations bought also the Ex1. I would bet they will get an "upgrade" from Sony!

Great news Paul, I expected that it would work well.

On another note - do you ever intercut your HV20 footage with the EX1? Just wondering as I also have both of these, and haven't done it just yet. If you have I was wondering how the HV20 held up. I have been to busy to try it, but have been thinking they might look OK together in good light

Graeme, here is a comparison between EX1 (TC2, and my preset) and a HV20.
http://rapidshare.com/files/93376520..._HV20.mp4.html

Dennis

IR Filter in action!!
 

Here you go....a before and after shot using the IR 486 Filter.
Top is with no filter...bottom is with the 486 IR Filter.

Here is the link to the filter that I bought: http://www.bhphotovideo.com/c/produc...=805&KBID=1062

So Paul, is this a kind of filter that you can leave on the camera permanently, and put the stock lens hood over it?

YES....the lens hood fits over it just fine.
I plan on just leaving it on all the time.
I haven't noticed any problems with it so far.

Good... I've just shot some indoor scenes where my daughter was wearing a dark-blue shirt; on the monitor it's magenta!

One thing still worries me, though: when using a 35mm adapter with different lenses, can it stay on the camera? Or will its reflecting IR rather than absorbing it be a problem?

@Zene:

Surely you're not relying on auto white balance?
And you're not using a ND filter indoors in low light?
And you're using enough light to eliminate the color noise?

I'm pretty sure it's a white balance problem because the color tint on the box corresponds to the color tint of the floor in each photo. There's a reason why pro cameras you allow you to set white balance manually, sir.

Anyone know where we can get these filters in the UK ?

Thanks,Paul.

Of course, all no, is IR contamination problem not wrong WB and not ND of course. Paul presented this can be resolve my problem with IR cut-off filter. HC3 is not pro and can change WB manually too :)

Definitely IR, has nothing to do with WB, or any PP settings. Interestingly enough, this happens on two other CMOS cameras I've worked with recently which cost MUCH more (RED and VR Phantom HD). Haven't noticed it with the Arri D-20, but I'll be at CSC on Tuesday and I'll look at it for fun. According to RED, they use as strong of an IR filter as is appropriate, partly an engineering problem. 3-chip designs require a LOT of optical engineering, so it makes sense for sony to use as light of a filter as possible behind the lens.

-Sean

A few quick tests with the 486...
 

First, I did point it at my remote and could see the IR light blinking. Then with the filter on, it removed it.

Second, I was shooting out my deck at 5600K at a pine tree. Adding the filter, quickly removed the warmth (from extra IR). You still had good reds and the rest of the colors, but there was absolutely extra red from IR. It was similar to the slight greenish look of Rayband sunglasses. NOTE - it also cuts UV too.

I did not see any increase in sharpness per say, but it did seem a tiny bit cleaner. I'm still waiting for a sunset and will give a before and after shots.

I will have my new laptop late next week, so I can finally offload and post footage and stills. Lastly the 486 comes with a nice lense cap too.

Thanks Paul.

Granted this is one shot and resized for the web, are you seeing a difference?

YES....so far, it seams to solve the IR contamination problem without creating other problems in the process.

Thanks Paul.

Hi

Im using a Cokin ND P154 (ND8 - 0.9) in front of my Canon FD lens and Letus EX. I can see a weird brown/magenta tint on the picture.

First pic is with the Cokin ND and the 2nd is without. Notice the color of my portabrace bag in the third pic. It looks magenta/pink instead of dark blue that it is. And the little camera bag besides the portabrace is supposed to look pink.

I dont see any change in colour when I put the Cokin ND it in front of my eye. Is this the same IR problem discussed in this thread?

Sami

Anyone have an opinion?

Sami

Sami,

While black fabrics do have the tendency to show brownish (just like the blue ones often show magenta), I guess in those particular grabs the main factor is WB being way too warm.

But my WB was the same in both shots, with and without the Cokin ND. Do you mean I should redo WB after putting the ND on?

I would... Yes, I know ideally the concept of the ND filter is not to affect wavelength.

yes you're right, if I redo the WB with the ND on it chances the reading by 200-300 kelvins.

So this means there is no way I can use my Cokin grad filter cause the lower half would need different WB.

Is this because the Cokin ND's are quite cheap or would this be the same with any ND with the EX1?

Now that's a good question.
I'm not sure who has deep enough pockets to find that one out. ;)