Posts Tagged ‘contrast’

My Video Is Fuzzy

Thursday, February 11th, 2010

This question came to me recently…

We have a cannon XHA1 and are having issues shooting dark objects inside. The pixels within the dark areas become noisy or fuzzy. It seems like lower shutter speeds help this issue but don’t resolve it all together.

If you are shooting video in low light and your camera is set to auto iris, the camera will maximize all available light to boost the exposure. This results in grainy, or noisy video. You can also introduce grain onto your video if you increase the camera’s gain to compensate for low light. Many video cameras with manual controls allow you to control the amount of gain, usually in increments ranging from 0db to 18db.

To ensure that your image is clear, sharp and clean, you need to ensure that there is enough light on set for a proper exposure. If your script requires that you shoot nighttime scenes, or scenes in dark interiors, remember that the illusion of darkness is created NOT by taking away the amount of light on set, but by increasing the amount of contrast. You can shoot nighttime scenes without grain by knowing how to properly light the set.

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Shooting the Grocery Store

Thursday, September 3rd, 2009

Twice this week I have been up all night working as the DP for Filament Artists’ latest short film, entitled “Love at the Grocery Store.” The screenplay was selected as the winner of the Production Prize at the 2008 Sidewalk Moving Picture Festival and will premiere at this year’s festival on September 26.

Shooting inside a grocery store has its particular set of challenges and so I wanted to pass along some things to remember if any of your projects take you inside the same environment.

LIGHTING & TONE

Most grocery stores are lit with fluorescents, meaning that everything will be washed with a flat, even, diffused light. If the tone of your piece calls for high-contrast lighting, you might want to see if the grocery store manager will allow you to turn off the overheads, giving you more freedom to light as you see fit. If this isn’t possible and you still want to create a surreal look with high-contrast, you can always light your subject with hard, direct light, that comes from the side, creating harsh shadows. The hard light will force you to stop down your f-stop. This should darken the background, while leaving your subject properly exposed.

Since fluorescent bulbs cast an even, diffused light, your subjects can come out looking drab, flat, and uninteresting. You will need some additional light to help create more natural skin tones and make colors that pop just a little more. However, reflectors alone won’t get the job done. They just won’t provide enough reflected light underneath fluorescent bulbs. And aiming a 1Kw or 650w tungsten at your actors will create an obvious difference in color and tone.

To give your shots a warmer look under fluorescent lighting, start by using your tungsten lamps and reflectors together. Mount a large piece of white foam core onto a c-stand and then bounce light from a 1Kw lamp onto your subject. The result is a soft, diffused light that isn’t overbearing, and yet one that warms up the scene a bit more. And I always recommend a little rim lighting to help your subjects stand out more from the background.

Bear in mind that the above solution assumes that you want a natural, warm tone for your project. If the mood of your film is a bit darker and somber, then you might like the sterile, flat, “blue” tone that the existing lights create.

LIGHTING & COLOR

Shooting under fluorescent lights can affect the white balance of your shot. If not properly monitored, the lights may cause the color of your shot to drift slowly from a cool tone to a warm tone, then back again.

However, I’d advise you to look back at our previous post for a more extensive look at shooting under fluorescents. To that article let me add that using a Kino light bank will be a big help. Kino’s do use fluorescent bulbs, but unlike the bulbs installed overhead in a grocery store, these bulbs burn at a constant color temperature. This will give your shots more accurate color representation while maintaining a consistent look with the rest of the lighting in the store.

Fluorescent lights might also appear green on camera. A green tone might work well for your project if the mood is more sinister and the location of your story more urban, decayed, or threatening.

Look for the comedy, “Love at a Grocery Store” at this year’s Sidewalk Moving Picture Festival. The screening is tentatively set for 9pm at the Alabama Power Building.

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A Crash Course On Color Bars

Tuesday, July 21st, 2009
SMPTE color bars

SMPTE color bars

Color bars are a necessary reference tool for anyone in video production. They help technical directors, camera operators, and editors calibrate their equipment to ensure accurate color representation and consistency across cameras and monitors. Knowing how to use them is important. A few years ago, I found a great tutorial at Video University on how to adjust your video monitor using color bars. Be sure to bookmark the article for future reference.

  1. Allow the monitor to warm up for a few minutes
  2. Dim the room lights and block any reflections on the monitor
  3. Feed color bars to the monitor either from a camera or “house bars”from your editing system
  4. Set the contrast also called “picture” to its midpoint
  5. Turn the chroma also called “color” all the way down until the color bars
    are shades of black and white

Next, you will need to adjust the brightness and the contrast of the image by using the three narrow bars at the bottom right.

barswhi3

Brightness

Notice the three narrow bars labeled 3.5, 7.5 and 11.5 on the bottom right. Adjust the brightness control until the middle (7.5 units) pluge bar is not quite visible. The lightest bar on the right (11.5 units) should be barely visible. If it’s not visible, turn the brightness up until it becomes visible.

Since 7.5 units is as dark as video gets, you should not see any difference between the left bar (3.5 units) and the middle bar (7.5 units). There should be no dividing line between these two bars. The only division you should see is between 11.5 and 7.5

Contrast

The next step is to set the contrast control for a proper white level. To do so, turn the contrast all the way up. The white (100 unit) bar will bloom and flare. Now turn the contrast down until this white bar just begins to respond.

Color

Adjust the hue of the monitor until the Yellow bar is a lemon yellow, with no shades of orange or green. Adjust the Magenta bar until you eliminate the red and the purple. If you aren’t confident in your ability to “eye-ball” these shades, consider the following:

Many professional monitors have a blue-only switch. If your monitor has one, switch it on. If your monitor does not have a blue-only switch, you can use a piece of blue lighting gel. Hold it to your eye like a viewing lens. If you see any of the red, green or yellow colors, double the blue gel over to increase the blue effect.

By using the blue-only switch or a piece of blue gel, you have removed the red and green elements of the picture. Only the blue remains. If the tint and color (also called “hue”) are correct, you should see alternating bars of equal intensity.

bluediag

  1. With the blue switch on (or your blue gel in front of your eye) turn the chroma or color until the grey bar at the far left and the blue bar at the far right are of equal brightness. One trick is to match either the gray or blue bar with its sub-bar.
  2. Adjust the hue control until the cyan and magenta bars are also of equal brightness.
  3. You can also match either of them with their sub-bars. Now the four bars – gray, blue, cyan, and magenta should be of equal intensity. The yellow, green and red (which are black in the diagram) should be completely black.

You should now have a properly adjusted video monitor. However, if flesh tones don’t look right, you may need to make further adjustments to the chroma and hue.

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