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Old June 11th, 2004, 02:08 PM   #1
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Specific filter question

Anyone know what filter is used to create a small flare whenever a light source exits the screen? I see it in a lot of movies (there's an example pic below -- look at the left side of the shot) ... it doesn't look like a fog filter of any kind, based on the cleanness of the lights before they leave. Is it a star filter of some sort?

http://mysite.verizon.net/res049li/grab107746.jpg
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Old June 12th, 2004, 02:11 PM   #2
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That doesnt look like a star filter as star filters will literally STAR or have Points. Perhaps a Soft Effects? Perhaps maybe its simply the nature of DV and bright lights?
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Old June 12th, 2004, 03:42 PM   #3
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Actually, I don't think I've ever seen it in DV -- that still is from a 35mm film.

I've posted a short (330k) video clip, but it's an extreme instance of what I'm talking about -- there are literally dozens of the flares. I've seen this effect used in films made on all different types of lenses, so I don't think it's a question of lens type.

Clip
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Old June 12th, 2004, 04:35 PM   #4
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Is there a (protection)filter in front of the lens?
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Old June 13th, 2004, 03:39 AM   #5
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Steve:

I couldn't load the clip, but from your description I believe what you are talking about is a side effect of using anamorphic (2:1) lenses, also known as Cinemascope or Super Panavision. One way to identify an anamorphic shot is to watch a point source of light go out of focus; if it becomes an oval, the film was shot with anamorphic lenses (Close Encounters of the Third Kind has lots of anamorphic flares and oval highlights, for instance).

I don't believe the 16:9 anamorphics used for DV replicate this effect, since it's a much gentler squeeze.

I have seen this flaring effect replicated to some degree with the use of a custom 2-point star filter (the two points being left and right).
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Old June 13th, 2004, 05:02 PM   #6
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Ooohhh yes indeed. Most of John Carpenters films as well; The Thing being an extreme example.
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Old June 13th, 2004, 07:57 PM   #7
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Actually, I think I know what you're talking about with that flare. It's generally a long blue line with an ovular center from headlights, flashlights, camera flashes, etc.

But this is something completely different. Those flares generally stretch across a good portion of the screen. These flares are small, more triangular in shape, and only appear when a light source exits or enters the frame, as opposed to emanating from said light source while it's on-screen (which is what you're talking about with the anamorphic flares in Carpenter movies).

Since some of you seem to be having a problem viewing the video, here's a still from it. Flares The flares you see at the top of the screen appear each time for a fragment of a second whenever one of those light sources leaves or enters the frame. That's about as big as they get too.
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Old June 13th, 2004, 10:04 PM   #8
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Gotcha! Steve, if I told you those flares were caused by a phenomenon known as...lens flare, would it be a disappointment??!

Seriously, that's all it is, and it's not due to a filter. It's just the optical characteristic that a cine lens demonstrates when a specular light source is just above the frame. I've dealt with them my whole career but never really speculated on why they are so "streaky" in this circumstance, it may have something to do with the angle at which they are striking the lens. Each manufacturer and generation of lenses deals with this phenomenon in a different way: some may streak more, others not at all.

It's one of my least favorite things to see in a Steadicam shot, incidentally--that streaky giveaway that a backlight is positioned just above the frame (and it usually bounces in and out a couple of times).

But of course in a shot like the one you posted, there's no getting around this when you pan down through a series of highlights (the streetlights, in this instance).
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Old June 14th, 2004, 04:32 AM   #9
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The reason why I wanted to know if there was anything in front of the lens is because I know that filters which have glossy metal rings (even black ones) can inject light when it hits under the right angles.
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Old June 14th, 2004, 05:21 AM   #10
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When looking at the movie somewhat closer I must conclude that he rim around the image plane (CCD) causes the streaks which aparently originate just at the borders of the images(horizontal and vertical). Flares coming from circulair devices (filter and lenses) don't show those specific image border originated
flares. What type of cam is showing this effect?
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Old June 14th, 2004, 01:06 PM   #11
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Charles:

Thanks! It's not a disappointment, but it certainly explains why so many films of so many types exhibit this characteristic. :)

Andre:

I'm not sure what was used. The film in question is an Iranian movie called "Crimson Gold" (IMDb), and I'm not sure what they shot it on.

One thing that led me to believe there was some kind of filter on the front is that, if you watch the vid, near the end, one of the streaks seems to end about an inch INSIDE the edge of the frame on a straight vertical edge. I've noticed this in other movies too -- "Punch Drunk Love" (during the first car conversation between Watson and Sandler) is another one.
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Old June 15th, 2004, 02:12 AM   #12
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Saving Private Ryan has some similar flares but I know some of the lenses were purposely "stripped of its protective coating" to induce similar effects.

Any chance this might be an issue with the lens coating?

Just asking as Im trying to learn :/
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Old June 15th, 2004, 07:58 AM   #13
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Steve,

Charles explains the reason why the flares occur, but it sounds like you are looking to duplicate this effect at will?

If so, Knoll Light factory has an excellent flare package, that duplicates various lens flairs and are completely keyframeable. So you can add an "anamorphic" flare... and put it where you want, as large, bright as you want and have it move.

I've used the effect a couple of times... pretty neat.
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Old July 3rd, 2004, 04:46 PM   #14
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I can't say I saw any "flare". It just looks like a shallow DOF to me.
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Old November 13th, 2006, 01:29 AM   #15
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Hey, I found something interesting from Vantage Film. It's some kind of filter use with anamorphic lens to exhibit blue horizontal flare intensionly but I think they don't sell it. It's called Vantage Blue-vision http://www.vantagefilm.com/en/news/n...-09_01_i.shtml
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