TIME LAPSE

It is important to build a procedure that will help you to avoid mistakes that can only be cured by a reshoot. Under the pressure of learning the equipment and new exposure problems, some practice is in order. For exposure, transparency film can be useful. One-hour prints will not be of much help for exposure determination unless you can "read" negatives. The one-hour tests can help you test for things like contrast control and amount of blur. The best of all possible worlds is to practice with the equipment that you will be using. The amount of film used is almost nil.

For sunrise and sunset I would suggest not "riding" the exposure until you are very sure of what you are doing. You can do some nice up to full exposure and down from full exposures that will look very good. To make a mistake trying to ride the stop can be a disaster. If you try riding the stop make sure that the exposure increases or decreases during the whole shot. If you are up to doing that you are beyond these simple instructions.

For sunsets it is pretty easy to start with full exposure and let the light fade until things are black at 4 stops under neutral gray. You can then open up and let the same shot fade again or try a different shot. For sunrise it is a different situation. You have to start about 4 stops underexposed and let the shot come up to full exposure. I have found that one shot from enough light to read up to the pinks of dawn is nice. Then another maybe different shot from pinks up to full sun. You have to know what the full light exposure should be by checking the exposure on a day before, if possible. The amount of clouds and smog will greatly effect that "full" exposure. Once the sun is up it isn't very interesting if there are no clouds to make moving shadows in the scene. I have found that an equivalent exposure of f 8. or f 11. for ASA 64 film to be a reasonable exposure for the sun lit scenes for the first 20 or 30 minutes after the sun is over the horizon. The clearness will have a lot to do with changing this. If you think that you have made a big mistake it might be safer to print a thin or heavy negative than try an exposure adjustment during the shot that will look just like that. When the clouds are playing with the sun a great range of exposures can happen. Watch the sky toward the sun to predict what might happen.

I have found that front and side light subjects have more interest. The high contrast of back light works well only with dramatic sunrises or sunsets leaving most things silhouette. (See Sunrise and Sunset Position)

Shots opposite and 90 degrees of a sunset get dark first. Shooting into the sunset should be your last shot.

If cars are included in your shot, some still tests can be very useful. I like cars to be very blurred and not to jump around. They will still record stopped if any stops in the scene for one frame. Using a 2 to 8 second exposure and a 1/8 second pull down works well. You will need heavy ND filters in daylight situations. Set the Norris motor 180 degrees out of sync. The interval becomes the exposure and the shutter speed becomes the pull down time. I have found with the Norris motor that using the shorter pull down times in the regular position that the exposures very a little. 1/2 sec. or longer exposures are no problem. (The Norris motor may have been upgraded.) (Higher voltage can help too.)

Here are some examples of exposure calculations. I recommend making manual exposure calculations and not just turning dials on the new computer light meters. Learn what every factor does to the exposure. (See Slow Speed Exposure)

1. We want a dark to pink dawn shot. Pentax spot meter reads EV 3 on the brightest object in frame. Putting EV 3 at 4 stops underexposed would be an f 8-11 at 1 second for ASA 64 film. When a neutral gray object in the frame gets up to full exposure, I start a new shot. You can also use your incident meter too. Leaving a little time to check the camera and make adjustments I then go for a dark to full light exposure. I add a 1.60 ND filter and select a full light exposure of say, f 8.0 @ 1/50 th (Sun over the horizon for the first 20 minutes.) The 1.60 ND allows you to read 1 second exposures at 1/50 of a second as you are used to doing. (1/50 sec = 1 sec. plus 1.60ND) (1/50 sec. = 2 sec. plus 2.00 ND) If you want more blur, use equivalent exposures: 1 sec. @ f 8.= 2 sec. @ f 11.= 4 sec. @ f 16 etc. The reason that I use the Pentax spot meter is it has the exposure dial that makes equivalent exposures easier to calculate.

2. Sunset. City. Sun is gone, lights start to come on. I found 4 sec.@ f 8.0 with a 1/8 sec. pull down (Norris motor 180 degrees out of sync.) worked well. The neon didn't burn out and still has color even though many stops overexposed. The pavements read neutral gray and the cars etc. looked good. The taillights streaked well. At a mistake exposure of 2 stops under all the pavement detail was lost at a printing light of 30.

Some things to think about.

1. Rain, wind, cold, mosquitoes.

2. Flashlight to check camera.

3. Cover the eyepiece well. Do not peek. An old eyecup will make a closing eyepiece when you don't have one. Tape sometimes doesn't stick well.

4. For people walking 1 sec. will stop feet some of the time, but not their bodies and legs. You can count and watch the frame to estimate the amount of blur at different exposure times.

5. Remember to reset frame counter each take.

6. Remove tripod-carrying pad to keep it from blowing in wind.

7. Cameras from air-conditioned rooms to humid warm outside will mist up. Same for cold camera into warm room in cold climate.

8. Look in the shot for things that may reflect when the light comes up. Cans, bottles, glass, and plastic bags to blow through frame.

9. If on a roof, be safe. Don't poke holes in peoples' roofing.

10. If there are building or bridge vibrations, check at a very long focal length to see if they will effect your shot.

11. Have spare meters and batteries. I use the spot meter most.

12. If you are using 18 volts or so into the Norris Mitchell motor, don't put 18 volts into your Arri regular motor. They have the same 4 pin Cannon plugs.

13. Open your lens capping shutter and shutter of your camera before unplugging for a camera move.

14. Reflected readings off buildings are best.

15. For commercials shoot more frames than needed to allow for frame cutting down to the most interesting shot.

16. The sky, especially if back lit, is generally hotter that you want and should be minimized.

17. There is a way to adjust the exposure using the 1/16,1/8,1/4 etc. but you need time between shots to make the adjustments and an error would be easy to make. Using the iris will effect depth of field.

18. Run enough film head and tail ( 5 to10') for the lab to splice your neg. when they develop.

19. Make careful notes.

Calculating frame rates.

Determine the screen time desired in frames

ie. 2 sec.X 24 frames= 48 frames

Decide shooting interval ei. 30 min.

Divide time by frames 30 min. By 48 = .625 min./frame

Convert to seconds per frame .625 x 60 = 37.5 sec./frame

So shoot one frame every approx. every 40 seconds.

If you can frame cut in editorial, multiply your number of frames by 4 or more. Often lighting doesn't change smoothly and can be improved by selective frame cutting.

© Copyright 1999-2004 Ron Dexter. All Rights Reserved.