by Bill Hurter
With advances in multi-pattern metering, in-camera metering has been vastly improved, however, one must still recognize those situations when a predominance of light or dark tones will unduly influence the meter reading and subsequent exposure.
IF you are using an incident meter but can’t physically get to your subject position to take a reading, you can meter the light at your location—provided it is the same as the lighting at the subject position.
EVALUATING EXPOSURE
There are two ways of evaluating exposure of the captured image: by judging the histogram and by evaluating the image on the camera’s LCD screen.
Histograms. By far, the most reliable way to judge exposure is using the histogram. This is a graph that indicates the number of pixels that exist for each brightness level. Histograms are scene-dependent. In other words, the number of pixels for each brightness level will directly relate to the subject brightness and how it is illuminated and captured.
When the photographer, Ann Hamilton, made a vignetted version of the high-key image (page 58) with more midtones and shadows, the histogram changed. It now covers the full length of the tonal scale.
Evaluating an LCD Image. With higher resolution LCDs, larger screens, and more functions in the playback mode of the camera, you can often use the LCD screen to evaluate images (although the changing light conditions found at most wedding shoots can sometimes make this less reliable than in other shooting circumstances).
Most professional DSLRs let you zoom and scroll across an image to evaluate details. This will tell you if the image is sharp or not. Also, you can set certain playback presets to automatically indicate problems like “clipped” highlights. These are regions of the image in which no detail is present.
WHITE BALANCE
White balance is the camera’s ability to correct color when shooting under a variety of different lighting conditions, including daylight, strobe, tungsten, fluorescent, and mixed lighting. Choosing the right white-balance setting is very important if you are shooting highest-quality JPEG files. It is less important when shooting in RAW file mode, since these files contain more data than the compressed JPEG files and are easily remedied later.
In a normally exposed image with an average range of highlights and shadows, the histogram will have the highest number of pixels in the midtones, as is seen here in this image by David Williams.
A low-key image, like this one made by Mercury Megaloudis of a Mercedes decked out with ribbons for the wedding day, has its data points concentrated in the shadow area of the histogram (the left side of the graph).
In a high-key image, such as this one by San Francisco wedding photographer, Ann Hamilton, the histogram has most of its image detail concentrated in the highlights (the right side of the histogram).
In a scene such as this one, illuminated by both daylight and incandescent lights, a custom white balance is a necessity. Sometimes trial and error (changing the white balance and viewing the LCD test exposure) can yield good results. Here the bias is more toward a true incandescent setting. Photograph by Bruno Mayor.
DSLRs have a variety of white-balance presets, such as daylight, incandescent, and fluorescent. Some also allow the photographer to dial in specific color temperatures in Kelvin degrees. These are often related to a time of day. For example, a pre-sunrise shoot might call for a white-balance setting of 2000°K, while heavy overcast lighting might call for a white-balance setting of 8000°K.
Most DSLRs also have a provision for creating a custom white-balance setting, which is essential in mixed-light conditions, most indoor available-light situations, and with studio strobes. Many photographers like to take a custom white-balance reading of any scene where they are unsure of the lighting mix. By selecting a white area in the scene and neutralizing it with the custom white balance, you can be assured of a fairly accurate color rendition.
OTHER CAMERA SETTINGS
Sharpening. In your camera’s presets or in your RAW file processing software, you will have a setting for image sharpening. You should choose none or low sharpening. The reason for this is that sharpening can eliminate data in an image and cause color shifts. Sharpening is best done after the other post-processing effects are complete.
Contrast. Contrast should be set to the lowest possible contrast setting.
Noise. Noise is a condition, not unlike excessive grain, that occurs when stray electronic information affects the sensor sites. It is made worse by heat, long exposures, and high ISOs. Noise shows up more in dark areas making evening and night photography problematic with digital capture. It is worth noting because it is one of the areas where digital capture is quite different from film capture. Some cameras have in their camera setup files noise-reduction filters designed for reducing the effects of noise in long exposures. Also, in RAW file processing programs noise can be minimized or eliminated with the use of several control settings.
Metadata. DSLRs give you the option of tagging your digital image files with data, which often includes date and time, as well as camera settings. Many photographers don’t even know where to find this information. In Photoshop, if you go to File>File Info you will see a range of data including caption and ID information. If you then go to EXIF data in the pull-down menu, you will see all of the data that the camera automatically tags with the file. Depending on camera model, various other information can be written to the EXIF file, which can be useful for either the client or lab. You can also add your copyright symbol (©) and notice either from within Photoshop or from your camera’s metadata setup files. Adobe Photoshop supports the information standard developed by the Newspaper Association of America (NAA) and the International Press Telecommunications Council (IPTC) to identify transmitted text and images. This standard includes entries for captions, keywords, categories, credits, and origins from Photoshop.
Fujifilm, the company that makes the Frontier digital printer, one of the most widely used lab printers, recommends that photographers “Stay inside the sRGB color space by capturing and working in the sRGB mode. If the photographer’s camera allows the ‘tagging’ of ICC profiles other than sRGB, we recommend selecting the sRGB option for file creation. The native color space of many professional digital cameras is sRGB, and Fujifilm recommends the sRGB option as the working space for file manipulation when using Adobe Photoshop along with a fully calibrated monitor. End users/photographers who alter the color space of the original file by using a space other than sRGB, without being fully ICC [color profiles for devices, including cameras, monitors, and printers] aware, are actually damaging the files that they submit to their labs.”
Reading between the lines, the reason Fuji is so adamant about the use of the sRBG color space is that their printers also operate in that color space. Lab operators would have to convert the files from Adobe 1998 RGB to sRGB, meaning one more step in the operation, but more important, the photographer would expect a certain rendition based on working in a wider gamut color space and perhaps be disappointed in seeing the finished lab results.
REFORMAT YOUR CARDS
After you backup your source files, it’s a good idea to reformat your CF cards. It isn’t enough to simply delete the images, because extraneous data may remain on the card causing data interference. After reformatting, you’re ready to use the CF card again.
Never format your cards prior to backing up your files to at least two sources. Some photographers shoot an entire job on a series of cards and take them back to the studio prior to performing any backup. Others refuse to fill an entire card at any time; instead opting to download, back up, and reformat cards directly during a shoot. This is a question of preference and security. Many photographers who shoot with a team of shooters train their assistants to perform these operations to guarantee the images are safe and in hand before anyone leaves the wedding.
COLOR SPACE
Many DSLRs allow you to shoot in either Adobe RGB 1998 or sRGB color space. There is considerable confusion over which of these i
s “right.” Adobe RGB 1998 is a wider-gamut color space than sRGB, so photographers reason that they should choose this in order to capture the maximum range of color. Professional digital imaging labs, however, use the sRGB color space for their digital printers. Therefore, professional photographers working in Adobe 1998 RGB will be somewhat disheartened when their files are reconfigured and output in the narrower color sRGB space.
As a compromise, many photographers who work in the JPEG format use the Adobe 1998 RGB color space all the time—right up to the point that their image files are sent to a printer or out to the lab for printing. The reasoning is that since the color gamut is wider with Adobe 1998 RGB, more control is afforded. Claude Jodoin is one such photographer. He likes to get the maximum amount of color information in the original file, edit the file in the same color space for maximum control of the image subtleties, then convert the image for output.
Is there ever a need for other color spaces? Yes. It depends on your particular workflow. For example, all the images you see in this book have been converted from their native sRGB or Adobe 1998 RGB color space to the CMYK color space for photomechanical printing. As a general preference, I prefer images from photographers be in the Adobe 1998 RGB color space as they seem to convert more naturally to CMYK.
RAW FILE FORMAT
What is RAW Mode? RAW is a general term for a variety of proprietary file formats such as Nikon’s .NEF, Canon’s .CRW and .CR2, and Olympus’ .ORF. While there are many different encoding strategies, in each case the file records the raw, unprocessed image-sensor data. RAW files consist of the image pixels themselves and the image metadata, which contains a variety of information about how the image was recorded.This is needed by RAW converters in order to process the RAW capture into an RGB image.
RAW File Converters. Because they include some additional metadata, RAW format image files must be converted by a RAW image converter before they can be utilized. These converters process the white balance, colorimetric data (the assigning of red, green, and blue to each pixel), Gamma correction, noise reduction, antialiasing (to avoid color artifacts), and sharpening. However, different converters use different algorithms; some process the tones with less contrast in order to provide editing maneuverability, others will increase the contrast of the file to achieve a more film-like rendition, for example. As a result, the same image may look different when processed by different RAW converter engines.
How JPEG Differs from RAW. When you shoot JPEG, a built-in RAW converter in the camera carries out all of the same tasks as described above to turn the RAW capture into a color image, then compresses it using JPEG compression. Some camera systems allow you to set parameters for this JPEG conversion—usually, a choice of sRGB or Adobe RGB 1998 color space, a sharpness setting, and a curve or contrast setting.
JPEG. JPEGs offer fairly limited editing ability, since the mode applies heavy compression to the color data. In the typical conversion process, the JPEG compression will discard roughly a stop of usable dynamic range, and you have very little control over what information gets discarded.
In some ways, shooting JPEGs is like shooting transparency film, while shooting RAW is more like shooting color-negative film. With JPEG, as with transparency film, you need to get everything right in the camera because there’s very little you can do to change it later. Shooting RAW mode provides considerable latitude in determining the tonal rendition and also offers much greater freedom in interpreting the color balance and saturation.
Marc Weisberg shoots a combination of RAW and JPEG files during the wedding day. He chooses RAW files for complex images, like those including mixed lighting or long exposures that might include a lot of image noise. Yet the JPEG mode is ideal for working quickly as in these images of the bride getting ready.
To resolve the disparity between RAW file formats, Adobe Systems introduced an open RAW file format, appropriately named the Digital Negative (DNG) format. Adobe is pushing digital camera manufacturers and imaging software developers to adopt the new DNG format. Unlike the numerous proprietary RAW formats out there, the DNG format was designed with enough flexibility built in to incorporate all the image data and metadata that any digital camera might generate. Proprietary RAW format images that are pulled into Photoshop can be saved to the new DNG file format with all the RAW characteristics being retained. DNG Save options include the ability to embed the original RAW file in the DNG file, to convert the image data to an interpolated format, and to vary the compression ratio of the accompanying JPEG preview image.
So why do many photographers still choose to shoot JPEGs? First, shooting in JPEG mode creates smaller files, so you can save more images per CF card or storage device. Second, compared to shooting RAW files, JPEGs do not take nearly as long to write to memory. Both factors allow you to work much faster—a clear advantage in some situations. If you shoot JPEGs, selecting the JPEG Fine mode (sometimes called JPEG Highest Quality) will apply the least compression and, therefore, produce the best possible files.
JPEG is a “lossy” format, meaning that images are subject to degradation by repeated opening and closing of the file. Therefore, most photographers who shoot in JPEG mode save the file as a JPEG copy each time they work on it or save it to the TIFF format. TIFF is a “lossless” format, meaning that images can be saved again and again without further degradation.
RAW. When you shoot in RAW mode, you get unparalleled control over the interpretation of the image. The only in-camera settings that have an effect on the captured pixels are ISO speed, shutter speed, and aperture setting. Everything else is under your control when you convert the RAW file—you can reinterpret the white balance, the colorimetric rendering, the tonal response, and the detail rendition (sharpening and noise reduction) with complete flexibility. Within limits (which vary from one RAW converter to another), you can even reinterpret the exposure compensation.
While RAW files offer the benefit of retaining the highest amount of image data from the original capture, they also take longer to write to the storage media and drastically reduce the number of files you can capture on a single CF card or microdrive because of their increased file size. Although the cost of media is coming down, the time it takes to record the information is not necessarily getting much faster. If the kind of shooting you do requires fast burst rates and lots of image files—exactly what wedding photographers experience—then RAW capture may not be your best choice.
Working in Adobe Camera RAW. Adobe Camera RAW, Adobe’s RAW file converter, is a sophisticated application within Photoshop that lets you far exceed the capabilities of what you can do to a JPEG file in the camera. For instance, by changing the color space from Adobe RGB 1998, a wide gamut color space, to ProPhoto RGB, an even wider gamut color space, it allows you to interpolate the color data in the RAW file upward.
Using the Advanced Settings in Adobe Camera RAW, you can adjust many of the image parameters with much more power and discrimination than you can in the camera. For instance, under the Detail menu, you can adjust image sharpness, luminance smoothing, and color noise reduction (luminance smoothing reduces grayscale noise, while color noise reduction reduces chroma noise). In the Adjust menu you can control white balance, exposure, shadow density, brightness, contrast, and color saturation. The Lens menu lets you adjust lens parameters that affect digital cameras, such as chromatic aberration and vignetting. These controls exist to allow you to make up for certain optical deficiencies in lenses, but can also be used for creative effects, as well—especially the vignetting control, which either adds or subtracts image density in the corners of the image. In the Calibrate menu, you can adjust the hue and saturation of each channel (RGB), as well as shadow tint. (Shadow tint is particularly useful, as it provides the basis for color correction of images with people in them. In traditional color printing, color correction is done to neutralize the tint in the shadows of the face and body, so they are gray or neutral. With shadow tint control, you isolate the shadows from the
rest of the image so that you can neutralize the shadows, while leaving a warm tone, for example, in the facial highlights.)
In the image shown here, the file was processed in Adobe Camera RAW. The number of pixels was quadrupled—from the chip’s native resolution of 2000x3000 pixels up to roughly 4000x6000 pixels.
Bridge is a sophisticated application that is a part of Adobe CS2. It allows you to work across applications and perform batch-processing operations.
Apple’s Aperture is an all-in-one post-production tool that provides everything photographers need for RAW file processing. Aperture offers an advanced and incredibly fast RAW workflow that makes working with a camera’s RAW images as easy as working with JPEGs. Built from the ground up for pros, Aperture features powerful compare and select tools, non-destructive image processing, color-managed printing, and custom web and book publishing. RAW images are maintained natively throughout Aperture without any intermediate conversion process, and can be retouched with exceptional results using a suite of tools designed especially for photographers.
In Photoshop CS2, Adobe Camera RAW combines with the modified file browser, called Bridge, to allow you to group a number of like files and correct them all the same way at the same time. This capability is a modified or selective batch processing that is much more useful than former means of batch processing. Plus you can continue working while the files process.]