Filter for IR contamination

[Les Nagy]

What I would like to see is Tiffen offer three filters that would fit the Sony ND filter wheel inside the camera so we could swap out the parts and never have to deal with external fixes again. Better yet, HEY SONY.......................

[Ed Kukla]

Originally Posted by Dean Sensui

Since I grade all my shots in Apple's Color, it's not a major deal to create and apply a color-correction vignette during post to deal with the green vignette problem.

Not easy if you zoom in on a shot; the green will shift outward as you zoom in and finally disapear at about 15mm. You'd have to keyframe your color correction.

[Dean Sensui]

Originally Posted by Ed Kukla

Not easy if you zoom in on a shot; the green will shift outward as you zoom in and finally disapear at about 15mm. You'd have to keyframe your color correction.

I keyframe spot corrections all the time. With the way Color works it's easily done.

[Leonard Levy]

Dean, Its great that you can correct your own green vignetting but you are apparently editing your own work. Many of us are not. I simply cannot hand a client an image with green vignetting and tell him don't worry you can fix that in color. Its out of the question.

His response would be - why are you using a defective camera on my job?

[Dean Sensui]

Originally Posted by Leonard Levy

Dean, Its great that you can correct your own green vignetting but you are apparently editing your own work. Many of us are not. I simply cannot hand a client an image with green vignetting and tell him don't worry you can fix that in color. Its out of the question.

His response would be - why are you using a defective camera on my job?

The current option would be to hand over footage with contaminated blacks. Until a better solution is put on the market, there's not much choice. Either fix it, or be stuck with how things are.

[Leonard Levy]

That's true, and why I'm hoping this Tiffen thing might work out.

[Ed Kukla]

Originally Posted by Leonard Levy

I just got off the phone with Tiffen and spent a bunch of time talking to Art Adams. As far as I can see there has not been a good reason Tiffen didn't make the IRND filter without ND . They thought this was a specific problem relating to ND issues and they didn't realize that the EX-1 behaved differently from other cameras. They thought it was the same as the Red.

The upshot is they said they will try to make a version of the IRND filter that eliminates the ND part , so it will be a yellowish green filter that you will need to white balance through

Cross your fingers, hopefully we'll know about this within a month.

Lenny Levy

And this will not be a Hot Mirror filter? It will work with W/A lenses???

[Derek Reich]

Originally Posted by Leonard Levy

That's true, and why I'm hoping this Tiffen thing might work out.

I could certainly be wrong about this (sure wouldn't be the first time) but my understanding about the Tiffen Color Core filters is that they are simply filters utilizing a color dye meant to correct for the far red contamination when you white balance through them. Since using ND filters allow more far red and less visible light to reach the sensor, this is why Tiffen manufactures the filter with different levels of dye for each level of ND that might be used. The more ND, the more color needed to to correct for the higher level of far red contamination proportionate to the lower level of visible light entering the camera. If this filter is manufactured without ND, then it will only be able to be effectively used when NO ND is used along with it. So, that means no in camera ND, no external ND. Otherwise, there may still be some far red contamination getting through since there won't be enough dye in the filter to correct for it.

That's my current understanding, and I would love to be proved otherwise, because if the Tiffen filter would work with all levels of ND equally effectively, then this would be an ideal filter. Maybe Tiffen is planning something new.... but there is a reason the IRNDs are offered as separate filters for each level of ND.

Since they are not hot mirrors, I assume they can be used in any position (not necessarily the first filter light hits) and they can be used with wide lenses

I think Les hit the nail on the head.... if the Sony internal NDs had the Color Core technology built-in with the correct amount of dye in each filter... this would be nearly ideal. (still would have a problem if additional external NDs were used such as when doing interval recording in daylight hours) but this would be an effective solution for 99% of shooting scenarios. Maybe we'll see something like this in future iterations of the camera, and maybe some new internal NDs might someday be offered to those of us who might want to upgrade?

This also begs the question: If the issue can be resolved by using a color dye filter and balancing through it, why can't this be cured with a custom profile set up specifically to correct for it? I know this was brought up before in this post.... but I don't know if anyone ever made any progress with that path.

[John De Rienzo]

Sure enough, this IR contamination happened to me at last weekends wedding shoot. I had an FX1 and the EX1 side by side for the ceremony, and decided not to use the EX1 as it was strikingling obvious it was going to be more trouble than what it's worth.

I called Sony Prime support in the UK yesterday and I was told they never heard of this problem, surprise, surprise!

When I went on to explain, they told me it was the difference betweem cmos and ccd sensor. What rubbish! When I explained further they said could it be chromatic abberation! sign....

I tried to direct them to this forum and samples and was told they have a strict policy not to read forums, thx Sony!

I don't think the filter is a great solution, albeit the only one at present, but this has really wound me up!

I can't even look at my EX1 of late,lol.....

Cheers.

[Leonard Levy]

Derek your analysis is correct, and I'm hoping they may be able to create a dye filter without ND that would be usable under tungstun. The idea of incorporating into the filter wheels is a good one, but considering the post immediately above I wouldn't hold my breath.
I'm going to run some tests today to see how the Tiffen IR ND3 works under tungstun light to see if one without ND would be a good idea.
Wish me luck

[Derek Reich]

Originally Posted by Leonard Levy

Derek your analysis is correct, and I'm hoping they may be able to create a dye filter without ND that would be usable under tungstun. The idea of incorporating into the filter wheels is a good one, but considering the post immediately above I wouldn't hold my breath.
I'm going to run some tests today to see how the Tiffen IR ND3 works under tungstun light to see if one without ND would be a good idea.
Wish me luck

Good luck, Leonard!

I would expect that if Tiffen does offer the filter without ND, that it would work just fine under tungsten lighting. But that limits a resolution for that shooting scenario only.... okay if most of your shooting is indoors. This is why I shied away from the Tiffen filters, because I don't want to have to buy 3-4 different versions of that filter with ND to cover most of my outdoor shooting scenarios. (certainly not at $250-$300/filter) Also, this would limit using an ND indoors to reduce DOF (if the contamination is present).

You're right about Sony..... I won't hold my breath. I love their products, but they are the most intractable people to deal with when it comes to customer service!

Looking forward to what you discover-
cheers

[Leonard Levy]

Bad initial news

I just tested a Tiffen IR N6 and an IRN3 (and both stacked together) on my Ex-1 under daylight and tungstun.
I found no notable difference in the red contamination of the 2 fabrics I used at all. This is a quick response to my shots and it might be that one fabric scored better than the other, but my bad one for sure was not much different if at all.

Disappointing and surprising after Art Adams' conclusions.

[Krikor Djevahirdjian]

Does anyone know the difference between the B+W 77mm 486 UV/IR Slim and the B+W 77mm 486 UV/IR? One is Slim and the other one is not.... but my question is does the not Slim model fit in the EX1 with the hood on?

[Leonard Levy]

Art and I plan to retest again next week so don't draw conclusions about IRND's yet.

[Kevin Cates]

Originally Posted by Krikor Djevahirdjian

Does anyone know the difference between the B+W 77mm 486 UV/IR Slim and the B+W 77mm 486 UV/IR? One is Slim and the other one is not.... but my question is does the not Slim model fit in the EX1 with the hood on?

Not sure about the UV/IR but I use the B+W 77mm UV and it fits with the lens hood on.