Consistent light betwwen scenes, shots and takes

[Brian Duke]

Hey,

It may be a really stupid question, but what is the best way to get consitent light between shots, scenes and takes (C.U., M.S. etc). For some reason my takes are all different llight even shot in same location etc. I am not a DP, but there must be a way to keep light etc consistent throughout the production. I ahve bought a number of DVD tuturiols about light but none explain it, except for a specific shot.

Any insights would help me. Maybe a light meter?

[Marcus Marchesseault]

I'm sure others with more experience can give you more tips, but there are a few basics.

Remember that if you zoom with your camera, the iris begins to close. If you are on the the edge of acceptable exposure and you zoom, you will underexpose. In this case, you need to add light to get your most challenging exposure within tolerable limits. Then, you can reduce exposure when you go wide.

Choose a direction from where you want your key light to seem like it is emanating. Keep that spot the direction your key is alway seeming to emanate. Don't flip the sides from which an actor's face is lit.

If you have practical lights in your scene, you can use them as an anchor point for your studio lights. For instance, a lamp in a living room can have a studio light behind it and out of camera. This way, you have a seemingly natural source that is enhanced by a more powerful light. If you want this to be your key and don't mind it being soft, you can bounce it off the wall behind the practical.

What problems in particular are you having?

[Steve House]

Originally Posted by Brian Duke

Hey,

It may be a really stupid question, but what is the best way to get consitent light between shots, scenes and takes (C.U., M.S. etc). For some reason my takes are all different llight even shot in same location etc. I am not a DP, but there must be a way to keep light etc consistent throughout the production. I ahve bought a number of DVD tuturiols about light but none explain it, except for a specific shot.

Any insights would help me. Maybe a light meter?

A light meter would help if the light itself changed between shots but the primary variable is light to subject distance, not camera to subject and that shouldn't be changing when you go from MS to CU, for example, unless you're relying on on-camera lights. Another variable is the camera and what its exposure controls are doing - auto exposure is usually the culprit in these sort of cases and a meter won't do anything to fix that. Marcus's comment on checking what happens as you zoom is well made - although when zooming a well-designed lens the iris chnge should be compensating for the focal length change to keep the light transmission (the so-called "t-stop") constant. The physical size of the iris at 30mm should be twice the diameter of the iris at 15mm in order to keep the same effective /f number in terms of light transmission.

One way to check is to get a large neutral grey card from the art store. Assuming you're NOT using a light on the camera. light it evenly and set you camera up about 10 feet away and adjust the zoom so the card fills the view and focus. Now zoom in to full telephoto position. The shade of grey should not change. Zoom back until the card again just fills the view. Pickup the camera and carry from 10 feet to 5 feet and refocus, the zoom being left alone. Again, the shade of grey should not change.

Also check to make sure that your new framing doesn't change the balance of light and darks in the scene or the brightness If your MS has the subject lit with a lot of dark background behind them and your CU is tight on just the face, the total light the metering sees is greater in the CU than it is in the MS and it will stop down the iris in response. This is where manual control becomes important. Set the exposure so the face is good in the CU, then switch to manual and without changing the exposure reframe for the MS.