Monthly Archives: April 2014

Light Metering

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010_AbqRailRunnerSleeperAnd now some bad news … light meters cannot be trusted at night.

But the good news … there’s no big mystery to understanding how light meters respond to nocturnal lighting conditions.

First of all, light meters don’t work in the dark, otherwise they would be called dark meters. When light meters fail, you are literally left in the dark, not knowing what to do next.

Secondly, light meters are overly influenced by light sources. Excluding light sources from your metering frame will remove the interference. Pointing your light meter in a different direction with similar lighting is the best approach.

If you are anticipating an expanded moment with incoming or outgoing light, you can trust a light meter reading taken without light sources. It is safe to vary your shutter speed a bit to capture the changes you’re after.

You need not worry about metering light sources directly, they will take care of themselves, as will lighting changes introduced during exposure.

Light meters only help us find the best “starting point” exposure. Keep in mind, you still need to Bracket to cover your ass.

Follow these steps to determine your “starting point” exposure when using your light meter:

HOW TO : Light Metering

  • review Bracketing steps outlined in Exposure Guidelines
  • pick your own aperture, or use the setting recommended in Aperture Settings
  • make sure your digital Auto Exposure (AE) is set to MANUAL

HOW TO : Light Metering Conditions

  • if light metering with light sources, go to Action #1
  • if light metering without light sources, equal shadows and highlights, go to Action #1
  • if light metering without light sources, more shadows than highlights, go to Action #2
  • if light metering without light sources, more highlights than shadows, go to Action #3
  • if light meter does not work because it is too dark, go to Action #4

HOW TO : Light Metering Actions

  1. use metered shutter speed for starting point exposure
  2. use double the shutter speed for starting point exposure
  3. use half the shutter speed for starting point exposure
  4. use 15 seconds for starting point shutter speed

IMAGE : Rail Runner & Sleeper, Albuquerque, NM

In 2010 I was one of six photographers selected by the Albuquerque Arts Program to photograph the city. My portfolio, “Rhythm of the Night”, depicts people and the city in motion. This is one image I shot for the assignment.

The Rail Runner is a commuter train that runs between Santa Fe and Belen. I went to the downtown station, and the first thing I noticed was this guy asleep on the bench.

To capture him with a train pulling into the station, I first set my aperture to f16 to handle the long depth of field.

The bright lights impacted my light meter, so I pointed my camera down, excluding the direct lights, to measure the proper shutter speed. I then doubled the shutter speed to record the details in the shadows.

Four trains came and went, and the sleeping guy never budged. This gave me the opportunity to capture more than one exposure of a train arriving while he slept.

The trains approached me very slowly, giving me the time I needed for my exposures. Eventually a train left and the guy was gone. I guess he woke up at the right time.

The small aperture setting created thinner light trails. It also increased the aperture starring of the bright lights.

The wide angle image was a 30 second exposure shot at f16 with TMAX 3200 film.

IMAGE TINT : GalleryWarmCool

I selected a warm tint with cool highlights to strengthen the tonal separation and enhance the clean, sharp look of the lights and light trails.

This B&W image was tinted in Adobe Photoshop with an ICC Profile I generated from my Mac App SuiteProfiler. The Profile was derived from the “GalleryWarmCool” Color Map created in SuiteProfiler.

Click these buttons to download the ICC Profile and SuiteProfiler Color Map:

EXERCISE : Light Metering

Challenge yourself by photographing scenes that are “too dark” and “too light”. That is, search for subjects that are difficult to meter, as well as ones that include light sources.

Follow the light metering steps to determine the “starting point” shutter speed for your desired aperture setting. Perform your bracketing steps as usual.

When there are light sources in your composition, practice metering by excluding the lights from your reading.

Record the exposure choices you made to begin each bracketing session. Review the results to learn from your experience using your light meter.

Be sure to review the Safety & Precautions page.

NEXT TIME : “The Eye In Discovery”

 

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Aperture Starring

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009_CarlsbadFootbridgeLightsThe stars come out at night … in more ways than one.

Most stationary light sources are seen as bright round spots to the naked eye.

But in an expanded moment, lights turn to stars through the eye of the camera.

Aperture openings are not round. They are polygons, constructed by overlapping blades that make up the diaphragm. Where the blades cross, corners are formed. When light passes through the aperture, the rays bend at the corners, and voilà … stars are born.

The number of spikes per star is twice the blade count in the diaphragm, i.e. two spikes per corner.  For an even number of blades, twin spikes may appear as a single spike.

As aperture size decreases, starring spikes become thinner and sharper. As exposure time increases, starring spikes grow longer.

Not all light sources are created equal. Starring of direct light sources is the strongest. Starring of diffused or covered light sources is weaker, and sometimes completely absent.

Starring varies with different lenses. How lens elements bend light plays a significant role in the formation of stars. Experience with a given lens is the best way to know what to expect.

You typically won’t see starring in your monitor or viewfinder. The effect emerges with time.

The recommended aperture setting described in my post aperture settings is a good starting point for Goldilocks starring … not too weak, not too strong.

IMAGE : Footbridge & Lights, Carlsbad, NM

This footbridge has crossed the Pecos River for as long as I can remember. As a kid I ran across it many times. It seemed endless.

I wanted to capture the length of the bridge stretching to the opposite shore. I placed my tripod on top of a nearby bench for a high angle shot. I stood on a step ladder to frame the image through my viewfinder.

This was taken on a clear winter night. The water was perfectly calm so the reflections were as intense as the lights.

The still, dark water made the bridge seem to float in mid air, even though it actually floats on the water.

This image is the result of a 30 second exposure shot at f11 with TMAX 3200 film. This created crisp starring of the light sources and reflections.

The smaller aperture was chosen for a long depth of field. I also shot this at f16 but found the starring to be too strong, overwhelming the importance of the footbridge.

IMAGE TINT : GallerySelenium

In the darkroom a slight Selenium toning creates a purplish tint in the darker tones and cools the highlights. I duplicated this tinting effect to emphasize the look of the starring in the brisk night air.

This B&W image was tinted in Adobe Photoshop with an ICC Profile I generated from my Mac App SuiteProfiler. The Profile was derived from the “GallerySelenium” Color Map created in SuiteProfiler.

Click these buttons to download the ICC Profile and SuiteProfiler Color Map:

EXERCISE : Aperture Starring

Compose an image containing light sources with your favorite lens.

Capture a wonder of stars via multiple bracketing sessions, each with a different aperture setting. Record your exposure information for each shot.

Examine the resulting images to see what amount of starring makes for a balanced image. Pay attention to how starring is affected by exposure time and aperture setting. Take note of what to expect for future image making.

Be sure to review the Safety & Precautions page.

NEXT TIME : “Light Metering”

 

Don’t miss my future posts! 

Subscribe to The Art of Night Photography by Email.

Support The Art of Night Photography.

Thank you!