Anybody know of lens filters to eliminate certain types of lighting?

[Wayne Morellini]

Hi. I have a practical issue. I want to do scenes where I want to eliminate different types of third party external lighting, and it occurred to me that there might be filters designed to match and block the frequencies of specific lights. Does anybody know of any?

 

[Karim D. Ghantous]

I don't know much, but it sounds like bandpass filters might be your money-melon. I have no experience with these things but I just know that they exist. They sound like things that are used only by research scientists. Therefore they may have no practical field use.

 

[Ben Scott]

NIsi are currently selling a minus yellow filter for shooting at night.

 

[Todd T]

I think you need to be a little more specifiic about what you are trying to accomplish.
The way your question reads now it looks like you are asking for a filter that can block hmi lights but not affect tungsten or LED.

 

[Patrick Tresch]

It will be difficult that one filter can match the specific spectrum of one light, and this without compromising the other ones.

 

[Wayne Morellini]

Ben, pretty neat little filters. Fantastic colors in those night samples. Thanks, I might get one just for general shooting at night.

They reduce the intensity of the highlights I want too, reducing the contrast towards the low end. Not enough, but better than nothing until I find something better. If they only made a filter design like I wanted to make they could squash the top way down to the mids or lower. I think some company did eventually do that active ND filter design I wanted, but I think only in camera. I've just realised a very good solution that would help, maybe stacked with this.

 

[Wayne Morellini]

Todd, and Pactrick. Yes, maybe I'm asking the wrong question.

I am looking at filming a short road scene at night simulating a blackout. The only time I can really shoot it without traffic is at night, so I can't easily use the old trick of filming in the day and simulating night. But at night it is lit up like a Christmas tree, so I have to bury those orangy yellow street lights before bringing it into post and finishing off the highlights. I need to squash the top down, well cut off the top too, as well as deal with the rest of the light pollution.

I have just considered while talking to Ben, that I should also look for a filter that is tuned to moonlight or star light, and stack it with the night light pollution filter Ben mentioned. That probably would really knock down the highlights too. Of course, I don't ussually talk about things like this, trying to achieve a new effect for the first time. But it's going be a hassle to archieve the other way I wanted.

 

[Wayne Morellini]

Does anybody know of filters for filming by moon or star light, while eliminating light pollution?

Or filters designed for particular street lighting types. This might target highlights a lot better, as the brightest highlights would be more the lights frequency curve then the color of the surface, which I could play with in setup. I'm forgetting, I could play with the pixel balance and gain too.

 

[Wayne Morellini]

Karim, great suggestion, but I imagine it's how you say.

I know some lighting has narrow band peaks, where this would help.

 

[Wayne Morellini]

Well, if I do get a multipoint Hydrogen, I could probably fit one of those night light pollution filter plates Ben mentioned, across all the lenses at the same time

 

[Patrick Tresch]

Or find the power supply of the city street light and switch it off. ;-)

 

[David Mullen ASC]

There's no filter that can reduce only the brightest parts of a broad-spectrum light source. There are narrow-band filters that cut certain wavelengths so if your light is just within that narrow range, it would get cut by the filter, but that also means that whatever that light is illuminating will also be darkened. But most streetlamps and other night sources are not within an extremely narrow band, and as I said, even if they were, a filter that cut them, if they were what was lighting the landscape, would also cut your overall exposure.

There is no filter that would make a night exterior look like the streetlamps and other light sources were turned off. Plus, if they were turned off, then what would be illuminating the scene? It would have to be the moon so you're back to simulating the look of a night exterior illuminated by the moon rather than by practical sources. Or is the look supposed to be pitch black other than a car's headlamp?

You're better off looking harder for a street that is empty during the day. Or if the idea is a unlit, dark street with only a pair of car headlamps shining, then finding an unlit empty road at night.

 

[PatrickFaith]

I've used the Lumicon filters (like the deep sky) a lot, I think those are some of the best.

Here's where I think they are nice to use:
1) the scene is in a area near a observatory where by law the city has specified the lighting (there's only a couple places in California that have done this)
2) The shot is primarily looking at the sky and/or hills and is not directly looking at a light/lamp (the filters are for removing atmospherics not direct source)
3) there is a lot of fog/smog/clouds where the city lights are reflecting the street lights (i.e. again the filters primarily remove atmospherics, not the direct source)

For actual narrative filming, like with a RED camera, I'd lean to it being kind of hopeless getting this to work. There is a chance you could get extremely lucky, but it would take a lot of testing and if the atmospheric conditions change it would all be for naught

 

[Marc Wielage]

I am looking at filming a short road scene at night simulating a blackout. The only time I can really shoot it without traffic is at night, so I can't easily use the old trick of filming in the day and simulating night. But at night it is lit up like a Christmas tree, so I have to bury those orangy yellow street lights before bringing it into post and finishing off the highlights. I need to squash the top down, well cut off the top too, as well as deal with the rest of the light pollution.

The right way to do this would be to pay the money, get permits, get the police to block off the area for several blocks, then get permission to turn the lights out and control what's being illuminated. But it won't be cheap.

It is possible to duck the highlights in post without making the rest of the picture too dark, if you do it carefully. Worst case, you could use VFX to dim or kill the lights with tracking masks. They manage to find enough parts of Georgia to shoot Walking Dead without any problem with electric lights being seen, so it can be done.

Day-for-night stuff is tough, but it can be done if you follow all the usual rules -- particularly to avoid showing the sky. When we do see the sky, I usually have to pull a key on the sky and bring it down, then also use masks to bring the rest of it way down to at least sorta/kinda simulate how nighttime really looks. The trick is to do this without introducing noise, and that requires some care and experimentation, depending on exposure and conditions. Shadows are another problem.

If you wind up shooting day-for-night, don't forget to shoot with the car headlights on. That's harder to simulate in post and never looks right (to me, anyway).

 

[Wayne Morellini]

Or find the power supply of the city street light and switch it off. ;-)

That would be a "federal" matter.

 

[Wayne Morellini]

There's no filter that can reduce only the brightest parts of a broad-spectrum light source. There are narrow-band filters that cut certain wavelengths so if your light is just within that narrow range, it would get cut by the filter, but that also means that whatever that light is illuminating will also be darkened. But most streetlamps and other night sources are not within an extremely narrow band, and as I said, even if they were, a filter that cut them, if they were what was lighting the landscape, would also cut your overall exposure.

There is no filter that would make a night exterior look like the streetlamps and other light sources were turned off. Plus, if they were turned off, then what would be illuminating the scene? It would have to be the moon so you're back to simulating the look of a night exterior illuminated by the moon rather than by practical sources. Or is the look supposed to be pitch black other than a car's headlamp?

You're better off looking harder for a street that is empty during the day. Or if the idea is a unlit, dark street with only a pair of car headlamps shining, then finding an unlit empty road at night.

That's why I thought a filter that was narrowed for moon or starlight might offer a better choice, when stacked with another night light pollution filter. The light is more normalised affecting reflections disproportionately at the first filter, then narrow banded by the second moon/starlight affecting reflections more (or stacked the other way, which ever works) then set up the camera color, then post to smooth it out and make it look more natural.

It would be a multi stage process of taking the light source down, and avoiding them directly in shot (though they can be clipped, or toned down in post). But it is the moving reflections that would be an issue, as the car moved through them. I want to deal with it at different stages of the light and then work flows to smooth it out. Marc, is here, he probably knows what I mean, as I looked at a post solution before. A good solution, widens the scenes I can incorporate.

As for location. I'm stuck with what I've got. I've compromised by moving the target location to a second option less difficult.

 

[Wayne Morellini]

The right way to do this would be to pay the money, get permits, get the police to block off the area for several blocks, then get permission to turn the lights out and control what's being illuminated. But it won't be cheap.

It is possible to duck the highlights in post without making the rest of the picture too dark, if you do it carefully. Worst case, you could use VFX to dim or kill the lights with tracking masks. They manage to find enough parts of Georgia to shoot Walking Dead without any problem with electric lights being seen, so it can be done.

Day-for-night stuff is tough, but it can be done if you follow all the usual rules -- particularly to avoid showing the sky. When we do see the sky, I usually have to pull a key on the sky and bring it down, then also use masks to bring the rest of it way down to at least sorta/kinda simulate how nighttime really looks. The trick is to do this without introducing noise, and that requires some care and experimentation, depending on exposure and conditions. Shadows are another problem.

If you wind up shooting day-for-night, don't forget to shoot with the car headlights on. That's harder to simulate in post and never looks right (to me, anyway).

Thanks Marc. That's more or less what I thought. I wanted to control before post to increase quality and ease of the post.

Yes, the cost would be way too high for a basic cost+equipment and time film challenge.

Yes, I aimed for lots and lots of testing before I even start. People just throw stuff together, but if you are going to make something basic, you can at least try to make what it is good.

 

[Marc Wielage]

Thanks Marc. That's more or less what I thought. I wanted to control before post to increase quality and ease of the post. Yes, the cost would be way too high for a basic cost+equipment and time film challenge.

It's totally kosher to experiment and shoot tests. You never know: some stuff that may seem like it isn't gonna work can actually work to a point.

I had a very tough scene in a horror film about 18 months ago where, due to an editorial decision they decided to take a day shot of a car driving through a wooded area and then stopping and make it a night shot. I think the four or five shots in this 90-second sequence took me the better part of 2-3 hours to do. Tons of work. I think I had seven or eight tracking masks going on, plus I tracked headlight beams from the front of the car through mist. Really tough. I don't think it looked great, but it was 700% better than what they had and the audience bought it.

If they had planned for it, there were five or six really simple things they could've done that would've cost nothing on set during production. But by the point I got the finished shots, it was too late. Crap like this happens.

 

[Remington Chase]

The lens cap cuts out most wavelengths of light.

 

[Karim D. Ghantous]

The lens cap cuts out most wavelengths of light.

Actually it does way, way more than that. It eliminates aberrations such as distortion, volume deformation, CA, astigmatism, decentering, vignetting etc. It eliminates the need to desqueeze anamorphic footage. It also eliminates focus shift, edge softness/smearing, and diffraction. However, it might increase noise, so be careful.