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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Problem with OLPF?

A

Alexander Ivanov

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Good afternoon.
I had had a problem with the OLPF Skintone filter. In suites he gives a pink flare. This defect is shown on border of light and a dark body for example. Not to correct it on post-production, and to remove less with a aperture than f.4 it isn't always possible. How to solve this problem.
This scene has been shot on LOMO ILLUMINA T1.3 35mm optics, with a aperure f2,8. The same effect is shown also when using Canon optics. The effect doesn't depend on optics. The camera has the latest firmware, doesn't give error messages.

 

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Here what is offered by RED:" I do see the defect in the image you sent, and was able to remove much of the issue by switching from DRAGONcolor2, to DRAGONcolor in the Color Space Menu."
But it only reduces effect, but doesn't clean it.
 
I have this occasionally. My 2 cents is its a combination of things. First, some chromatic aberration in the lens causes some pink (and sometimes green but that's not the problems here) fringing around the border from bright to dark areas. This is usually not too big a deal as some lenses are better than others with CA. But somewhere in the color space sauce ( some choices are worse than others...Red gamma 4 I believe is the worst) this very specific pink is amplified and exaggerated to unacceptable levels. Yes you can modulate it somewhat with other gamma and color space choices but its still there. It is present in my CFWeapon just as it was in my earlier Dragon. It is ugly and I would like to get rid of it. Often I shoot slow motion shots with strong backlight (the Sun) and bad as it looks in real time its awful in slo-mo. I have been able to avoid for the most part and I do see that using cheaper i.e..more CA prone lenses makes this much worse. Basically if you have CA in your lens you may get this somewhere down the road. I'm pretty certain a master prime will not show this effect. If anyone has any other suggestions other than the stock... change gammas or color space, I'm all ears.


Probably the only thing I have a real problem with my nifty Weapon....
 
I had this issue on a couple of shots on one of my recent features.

It's definitely not (only) lens related. Avoiding DC2 helps but it doesn't get rid of the problem.

Maybe implementing in RCX and the SDK a slider with a code similar to LR defringing could help if it's an OLPF and non-solvable issue??
 
Hi Guys,

to correct this set your footage to Dragon color instead of Dragon color 2. There are sometimes some "hot" colors when processing with dragoncolor2. That could be CA related as well. Any filtration? Can you post an R3D?

David
 
It occasionally I find him but only when use certain lenses, but they are the same idea of Taylor ,i think is a problem lens CA.
If for example I always use the Xeen lens and some Canon then often have this defect.
And All OLPF do this.
As David said, you can choose Dragoncolor and much of the problem go away, but it does not always help.

I never had see this,
some lenses tested.:


Sigma 18-35
Tamron 18-50v2
Master Prime Zeiss
Ultra prime Zeiss
Cooke S4 and Mini
Zeiss superspeed mk2 / mk3
Zeiss zoom 28-80
Canon 70-200
Zeiss ZF

Had with:

Xeen
Canon ef / FD but only a few focal.

Linear and DRagoncolor and dragoncolor2..as you see in linear, the problem is already present after the lens.

5_zpsb1urejkj.jpg
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I had this shooting withalmost every lens, including Cooke S4/i, Ultra Primes (especially on wider FLs) and in one shot also with a Zeiss 35mm CP.2.

Again, it's not (only) lens related.

At the very least these CAs are EXTREMELY amplified.
 
You can say that you've had focal problems on cooke s4 and ultraprime? I can not play it with the Weapon with the same shot, now. But perhaps you used focal lengths that I have not.
So I can do some tests.

ALexa Mini also have (Xeen lens 85mm ) mmm!! as picture below.
However you are right TOmmaso , Dragoncolor 2 very amplifies the defect ... Maybe there 'another in more.

alexa_zpsfcbpy6nk.jpg
[/URL][/IMG]
 
I had this tonight with the Standard OLPF. It's dragoncolor2, switching to Dragoncolor solved it.

David
 
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It is annoying, but not that big of a deal, as say, aliasing, which is much more difficult to remove.
Here is a quick 5 minutes grade with before and after.

Graded



Ungraded



P.S. Switching to DragonColor reduces the problem, but doesn't fully remove it. Ungraded image has only the DragonColor switch, which, clearly is not enough.
 
The purple comes from chromatic aberration on the lens, and is typically visible in any fast lens shot wide open. The issue with DC2 is that the colour produced by the CA is out of gamut for DC2 but in-gamut of DC.

Graeme
 
Somebody can check this effect with Low Light OLPF? With Standard OLPF the same effect, but when shot this scene the camera with Low Light OLPF had no such effect.
 
AS I stated. This has happened to be on 80mm and 35mm at 1.4 with standard OLPF.

As graeme has already stated the problem is due to CA and DragonColor 2. Illumina's at t1.3 have similar CA to Zeiss superspeeds. You'd might end up with cleaner final product if you closed down a half stop and added the exposure back in post.
 
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