Getting and keeping the highest image quality

A number of issues factor into getting the highest image quality, and they occur at both the pre-pixel and postpixel phases of your workflow. Some involve common sense, while others may require you to take some specific technical steps to preserve your images and present them in their best possible way.

CAMERA CARE

Whenever possible, it’s always best to begin a photo shoot with a clean camera that’s free from spots on the image sensor or dirty lens glass. And keeping your gear in good working condition means that you will be able to rely on it more to operate perfectly in any situation. Still, before the shoot you may want to take a test shot and download it to your computer for a quick check.

It’s a good idea to clean your lenses and image sensor before any shoot, as well as just after you’ve finished.

Ensure that the outside of your camera is wiped free of oils and dust, as well. This ensures that when you change lenses, you don’t accidentally get unwanted particles inside the camera. And when you change lenses, do it in a clean, dry, and nonwindy place if at all possible.

OPTIMIZING AND ADAPTING TO YOUR ENVIRONMENT

There are a few factors you need to consider before every shoot that will help you to control your image quality in any situation. You may not always be able to control the light, for example, but you can adjust your camera settings to make the best use of the available light. And, considering the ultimate purpose and use of your photos before you take that first photo can also maximize the quality and usability of your images. Monitoring your white balance, ensuring your camera is set to the right format and image size, and checking your Picture Style settings can all impact your image quality overall, so don’t neglect these tasks.

  • Set and check your lighting in a shoot where you have control over your subject (such as in the studio, where you can use portable lights or even a flash). Taking the extra time to set things up right the first time pays off. When you control the lights, don’t just adjust your camera to suit whatever the lighting happens to be set to from the last shoot (you’d be amazed at how often photographers simply get a little lazy and don’t bother!). If you can get the lighting set so that you can drop your ISO to a lower setting, your image quality will improve and you’ll have more range of exposure for the photos.
  • Know what the potential use of your images will be, and adapt your image size accordingly. If you know that you’re shooting for photos that will only be displayed on the Web, you may not need to be taking large JPEGs, for example, because they are usually only displayed onscreen at around 96 ppi (pixels per inch). However, if you are going to print images, they need to be sufficiently large for how they will ultimately be printed. If it’s going to be at least an 8 X 10 or larger, you definitely want to shoot at a large setting; furthermore, if you’re going to crop images, you’ll want to make sure that the cropped area is sufficiently large (another reason to shoot at a large setting).
  • If you’re shooting where you can’t change the lighting, explore where you can stand or situate yourself for the shoot to ensure the best-quality light. What’s the ambient light like? Are any other lights being turned on or off? How close can you get to your subject? Where can you optimize your ability for the best possible exposure and lowest ISO setting? Are you using the right lens for the job, ensuring that you don’t have to crop more than necessary out of the final image?
  • Check and double-check your white balance by taking multiple exposures set to the same balance. Using your Auto White Balance (AWB) setting can be dicey if there is mixed light as it may not lock on to the type of light for which you want to be balanced. In a variety of light sources, such as sunlight, fluorescent light, and tungsten light, your AWB will adjust to any one of those depending on how the camera measures the subject. If you’re walking through an event taking photos of multiple subjects — say, for example, a wedding reception — then the AWB can be very handy, especially if you don’t have time to double-check and retake photos. If you’re photographing in a home for an architectural shoot, for example, where your exposures need to be excellent and the light is similarly variable (sunlight, fluorescent, and tungsten), take the time to use a manual white balance setting and take test shots before shooting final images. Also, shooting in RAW will definitely be an advantage because if all else fails, you can adjust the white balance later in post processing.
  • Use your Canon Picture Styles to your best advantage. It will help your colors and white balance, as well as optimize images as they are taken so that you’ll have less to do when you begin editing.

OPTIMIZING DIGITAL IMAGE QUALITY

There are essentially two types of file quality within all the digital file formats: lossy and lossless. Lossy files, such as the JPEG format, degrade as they are saved and saved again over multiple generations. Lossless is the opposite — these files do not lose image quality when you save them. TIFF files are lossless and are the format that many photographers use when doing image editing if they will be saving multiple generations of an image. You can save a RAW file to a TIFF.

JPEG is the most common digital image format today, particularly on the Web, and it is produced by virtually all digital cameras. However, when working with JPEGs you have to be sure you don’t keep resaving the same file, lest the quality become noticeably bad. While the difference will be unnoticeable over a few saves, as you can see in 9-5 through 9-8, JPEGs do, in fact, lose quality over time and after multiple saves.

These four images are from the same JPEG file that has been saved multiple times. 9-5 is the full, original JPEG file as it came out of the camera. 9-6 is a close-up from the original, while 9-7 is the image after being resaved ten times. 9-8 has been resaved 20 times. Note the significant and progressive loss of quality and increased pixila-tion. Original photo ISO 100, f/3.2, 1/200 second with a 1D Mark Iln and an EF 70-200mm f/2.8L lens.

JPEG files compress the data that makes up the image — taking away information that the software deems to be unimportant — so that the image is as small a file size as possible. And while saving a JPEG file a few times won’t produce noticeable artifacts, doing it much more than that will. Note that just opening and closing a file won’t affect it — it reduces quality as multiple generations of the file are created. So if you copy a JPEG into multiple same-generation images with different filenames, the images in the same generation will have equal quality; however, if you copy and save a file, then copy and save the second file, then copy and save the third file, and so on, you are progressively degrading the image’s quality from the original and creating an increasing amount of pixilation.

TIFF is the most common lossless file format. It is widely supported, although not produced by very many cameras primarily because so many cameras now produce RAW files instead, which can be used to create very good TIFF files. In order to retain your very best image quality, and if you will use your images frequently and save and resave them for multiple generations, it’s highly recommended that you work in TIFF since it’s the most common lossless format. Another great attribute of TIFF is that it supports multiple layers in Photoshop so that if you add various layers of images, text, and so on, you won’t have to have the image “flattened” when you save it and you’ll be able to go back and make changes that wouldn’t be an option from a JPEG file.

Another lossless format is BMP (Windows Bitmap). It has been the standard bitmap storage format used in Microsoft Windows and supported by most image-editing programs, though it is becoming much less common in most applications today.

RAW files are, as implied by the name, “raw” image data that is not compressed, manipulated, or adjusted; essentially, they are images in a format that is as close to how the camera “sees” the image as possible. The information comes straight from your image sensor. The files are large, and you cannot work on and save a RAW file; you must save it as another format such as TIFF (most commonly) or JPEG.

When you shoot in RAW and you want your image to retain its original quality no matter how many generations of the image are produced, you’ll need to save your image in TIFF (or BMP). Although there is a small amount of compression applied to these files, they are much larger than JPEG. For example, the image seen in 9-6 is 1,532KB in JPEG format, 23,981KB in BMP format, and 23,986KB in TIFF.

What that translates to for your day-to-day workflow is that you’ll have more flexibility in editing TIFF files for tonal adjustments such as curves and levels, brightness/contrast, white balance, shadows and highlights, and overall exposure. For example, if you photograph a bride and groom, wearing a white dress and a black tuxedo, respectively, when you’re editing you may want to selectively edit facial tones as well as bring out highlights in the dress and tuxedo. Shooting in RAW gives you much more flexibility when making adjustments, without causing posterization or other low-bit-quality issues.


TIP

If you’re shooting in RAW, your image files will already be at their largest possible size. If your images are going to be used for both the Web and for print, you may want to shoot in RAW+medium JPEG so that you already have a JPEG to use for the Web and so the RAW file can be processed for print.

Category: Photography Workflow

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