David Saffir: Managing Exposure, Lighting, and Color
May 2013 16

This is the first in a series of articles discussing proactive management of key elements involved in creating high-quality digital images. In this segment, I’ll review use of the SpyderCUBE in managing dynamic range and exposure.

Revisiting The Zone System

The simplest take-away from the oft-misunderstood Zone System, is that an image should be exposed to utilize the most or all of the range from black to white, without unintended clipping of near-whites, or blocking up of near- blacks. If the image does not incorporate the full dynamic range in a scene, the photographer should have done this by intent.

In digital photography, the most commonly recommended camera settings involve protecting detail in the brightest parts of the image, and correcting everything else in post-processing.

Errors that Affect Image Quality

It’s true that the biggest image-killer is over-exposing the whites, preceded only by the errors of blur and incorrect focus. Please don’t make the mistake of assuming that these last two items are not relevant to this article: camera settings can cause camera-blur, or motion-blur, as well as shorter or longer than desired focal zones.

Other errors that are difficult, if not impossible to correct in post-processing include noise from excessively high ISO settings, and noise in the darks from too short an exposure or too restricted an aperture.

Options in Managing Exposure
Too often, a camera’s internal meter misses optimal exposure, or sets the needed exposure range at the expense of some other factor, such as a too-high ISO, or a shortened focal range. We need another method of determining settings that will consistently improve results.

Some of you may be familiar with the Datacolor product called the SpyderCUBE If so, you have read the descriptions or seen the videos about using it for optimizing adjustments in post-processing, ideally in a RAW converter.

However, that’s not the only way in which the SpyderCUBE can be used: it’s also an effective tool for determining optimal camera settings – to “get it right, in the camera”.

In-camera White balance

  • Set camera white balance
  • Determine setup for the “top”: Zones 8, 9, and 10, the “bottom”: Zones 1, 2, and 3, and the “middle”: Zones 5 and 6.
  • Further manage adjustments in post production/processing of RAW files

You can use the SpyderCUBE to set in-camera custom white balance. Simply enough, set the SpyderCUBE up in your shot, under your lighting. Initiate your camera’s custom white balance sequence, fill the frame as much as practical with the Cube, and set the white balance.

Setting white balance in this way maximizes the usefulness of your camera’s LCD display, which shows you a semi-processed JPEG, not your actual RAW file. Color and density will be more representative of the real thing, and the camera’s white clipping tool (the “blinkies”) will be more accurate.

Evaluating Exposure Using the SpyderCUBE

Next, we’ll try to find the “top” of the exposure.

Start in Aperture priority mode, use either spot metering or center-weighted metering, and take a test shot with both sides of the white/gray faces on the SpyderCUBE showing equally. Examine the on-screen preview – while you are at it, review the histogram, and take a close look at the appearance of the chrome ball and the white faces.

One expects to see the “blinkies” appear on the highlight reflections on the chrome ball; that assures they are spectral highlights, and indicates Zone 10. You don’t want to see blinkies in the white faces – that would mean you’re losing ground in Zone 9 and Zone 8. The highlight detail would suffer in the image – and probably won’t be recoverable in post-production.

You can use the black face of the SpyderCUBE, and the black trap it contains, to adjust exposure for the shadows, and control of zones 1 through 3. You’ll want an exposure that lets you clearly distinguish the trap in the black face of the Cube. Not only will this help you to protect shadow detail, it will help you reduce noise in post-production.

Make your adjustments, take note of your exposure settings, and switch to Manual mode. You can calculate adjustments to aperture/shutter speed to manage depth of field and control motion-blur.

At this point, you have better control of your exposure. You may now have the option of reducing your ISO settings, as you are controlling your other settings, and not guessing – so you need less buffer or safety margin. Similarly, you have more latitude in choosing your combination of aperture and shutter speed, again because of reduced margin for error.

A final consideration is the density of the gray faces. This is best analyzed in tethered mode, or in Post-processing, but a quick judgment of whether they are indeed medium gray, not lighter or darker than intended, can increase awareness of image densities, and control whether you are creating a high-key, or a low-key image.

David Saffir is a commercial and fine art photographer and printmaker, located in Southern California, and a well-known speaker at workshops and conferences across the US.