Art,

Are you referring to purely vertical bright lines extending from any specular ("bright") lightsource?

If so, that is called vertical smear and is caused by the CCDs (not related to whether the video is recorded in an analog or digital format).

Pro cameras use a more expensive type of CCD (FIT, HAD, etc.) to avoid this problem or use some other tricks (Ikegami for example).

The CCD pixelshifting used in some prosumer cameras also reduces this problem (XL1 and several others).

CourseDesign,

What you described is exactly what I am talking about. Unfortunately I have a rather entry level, 1 ccd camera. Is there anything I can do to minimize the verticle smear?

Thanks

Is there anything I can do to minimize the verticle smear?

Short of using a filter of some kind (fog, star, etc.) to try to minimize the streak, there's not much you can do about it :-(
Another thought is to use some kind of a "flag" (a large piece of flat black cardboard carefully positioned over the lens) in an attempt to block the light from entering in the first place. This may require a lot of experimentation to find the right position.

Mike

RS170a,

Excuse my ignorance, but when you say filter, are you referring to a filter on my camera lens? Or a filter applied in vegas during post?

Maybe you should shoot day for night (La nuit americaine). Do a search here and at the vasst site. I'm sure you'll find something.
Tor

Dave, I'm referring to a filter on the lens itself. Trust me when I say that trying to "fix it in post" is not an option with this kind of streaking.
Tor's suggestion about shooting it "day for night" is a possibility but even that style has it's own problems.

Mike

A couple of other thoughts.
Modify the light source if possible so the actual source itself isn't shining into the lens. To state the bleeding obvious, make certain the lens is VERY clean. Matte box might help, you can buy very cheap ones made from fabric. Lastly try shooting before the sky is totally black i.e. reduce the contrast of the scene.
As said before, these problems are not ones to tackle in post.
Bob.

Just to elaborate on some of the ideas, this vertical line is a function of the electronics of the camera and is being caused because the light is in the shot. This is not the same as a lens flare, where the spill can be flagged out of the lens. (Usually, a key grip will actually look down the lens to see if light is spilling in. Then she'll flag the heck out of it.) You can't flag a light if it's supposed to be in the frame.

Options could include reducing the light output from the fixture with a dimmer, ND gel, or perhaps treating the fixture with wire screen to reduce the output. The idea here is to get the light down to a level where it appears bright but isn't actually blowing out the electronics.

Good Luck!

Rob Mack

rmack hit it on the spot. we have used these techniques often, the dimmer works great, youll be amazed of how little light you need for it to show up in your shot and look well, more exspensive then gels, which we have often used. i prefer using dimmers becasue it is so easy to adjust the output. in many cases for outdoor lights we will use our own bulb/dimmer setup instead of trying to rewire the light. this works for most cases when the cord wont be seen or can be hidden

Just to elaborate on some of the ideas...

You're absolutely right on all your suggestions Rob.
My mistake was in assuming that he didn't need to see the light.
I have to remember to carefully read the posts before responding :-)

Mike

Rob,

So if I put a lower watt bulb in these fixtures, that might reduce the verticle smear?

Thanks to everyone for their advice on this.

The only thing to do is to try it and see what happens. You may have to down to a 10 watt lamp before it ceases to be a problem and, even then, it may still smear on you. Rob's suggestion about a dimmer is the best idea.
If that's not an option, a low wattage bulb and some kind of diffusion material (to really soften it) is another possibility.

Mike

Diffusion can help some to just make the source look a little bigger. Making it not be a point source might help out.

You can also relamp and use a dimmer on the new lamp. The reason to do both is that dimming tends to warm the light anyway so if you can get the lamp down to 40 watts in the first place then you don't have to dimm so much. Below 40 watts, most household bulbs are already really red even without dimming.

I was kind of allowing that the outdoor porch bulb might be some sort of sodium vapor lamp. If so, then you can't dim it and the ND gel, diffusion, or wire screen might be your only choice. The wire screen will hold up to heat the best but be careful-you could conceivably melt aluminum screen, I suppose.

You can get little dimmers that go into a light socket. Sometimes these work out well if they'll fit, although they can raise the lamp unnaturally high. Good to have in your kit, along with a variety of houshold bulbs, cube taps, ground lifters, etc. Also really handy are little screw-in circuit breakers that replace fuses. These have a pushbutton to reset them and are a lot more convenient than replacing a fuse 6 or 7 times in a night.

Rob Mack

Sorry guys but I think we've lost the plot. The idea of dimming bright light source if fine if they're not the only light source. But if I read the original idea they are the primary light sources and making them dimmer is just, well going to mean wider iris and more gain and more noise, not a good thing.
The trick is, if you're doing the full production number, light the subject with as much light as you need to get a decent stop. Then introduce practicals that have just enough light so they look like the light sources without causing problems. You might think there's just one street light lighting the alley but most likely there's a 20K on a crane out of shot aimed so it look like the light is coming from the street light.
Obviously this productions budget cannot afford that, so use a a free light source, the sun. Street lights come on at dusk, not when it's pitch black, so that is about the ideal time to shoot ot maybe a bit after. You might need to do a bit of work in post to push the shadows into black but that should be easy because you're pushing any noise down.
Bob.

This is probably the best course in this case because the lights are in the shot and not all of them are treatable- it's hard to do anything with a streetlight unless you rent a lift and just go down the street and deal with each one. If you can do that you can also afford other measures.

The biggest problem with shooting at dawn or dusk is that the light levels are changing rapidly. It really pays off to make sure you're totally ready well before the time to shoot. If appropriate, leave your self a little extra time to do a run through before shooting. I can't tell you how many times I've seen shots missed because of a snag at dusk that delayed the shot by ten minutes.

Rob Mack