Category: camera

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Post-processing workflow

In the last two posts I presented data about how "successful" my picture taking has been and what common disasters immediately ruin a photograph. On this post I will address how non-catastrophic photo errors can be corrected in the post-processing phase or the "electronic darkroom."

Most snapshot photographers take a photo and allow the in-camera processor to create an image that can be viewed, shared or printed.  Usually, these images are in a file format called Joint Photographic Experts Group or JPEG.  JPEG is the most common file format used on the internet and is a compressed 8-bit file that has been around since the early 1990s. There are three concerns for serious photographers about capturing images in the JPEG format: 1) JPEG is a compressed format so much of the image data is thrown away during the compression in order to make the file size much smaller, 2) JPEG uses a lossy compression algorithm, meaning that every time the file is changed and saved it is re-compressed causing further loss of image data (the picture quality deteriorates), and 3) JPEG is (almost always) an 8-bit format that does not lend itself well to significant image manipulation in common software programs such as Adobe Lightroom or Photoshop. So what is the alternative to JPEG?

Digital cameras capture an image from the sensor in a RAW format.  The RAW files contain luminance (brightness or intensity), redness, greenness, and blueness data from every single pixel in the sensor.  This creates a huge 12 or 14-bit file that is not viewable without processing by additional software. The RAW data are compressed and converted to JPEG files for viewing in the camera and, depending on the camera quality and settings, are saved as JPEG, RAW, or both file types. Most advanced photographers save their images as RAW files so they can be saved and manipulated as needed without worry about data loss caused by file compression. The RAW files can be digitally manipulated over and over and the images will not lose data or quality. The RAW files have many different names depending upon the brand of camera used.  Canon names their RAW files with the extension .CR2 and Nikon uses the file extension .NEF, in any regard, these are RAW files. I allow the editing software to convert my Canon .CR2 files into .DNG (digital negatives), a non-compressed, open-source file type that is common to almost all RAW processing programs.  Conversion of any RAW file is necessary for viewing, sharing and printing and many file formats can be created from the RAW files.  The common formats are JPEG, TIFF, PSD, GIF, and PNG. The differences in these formats are not important now.

So, the point of this posting was to overview the workflow that I use to prepare RAW images for viewing, sharing or printing. I use Adobe Lightroom for 90+ percent of my post-processing and use Photoshop for most of the last 5-10%. Lightroom is a database program optimized for photography.  It catalogs the images so I can find what I want from more than 35,000 images in a few seconds but it is also a powerful image editing tool that is non-destructive and reversible. 

When I import a file from the memory card of my camera, I follow a specific workflow to prepare the images for viewing. First, I rename the images to the day's photoshoot combined with the camera-generated file number, and, at the same time, I tag each images with searchable keywords that indicate the state, season, subject, and special tags for other processing. While this occurs during the image import, I look for the 5 causes of failures and delete these images on the spot. During the file import, I allow Lightroom to perform common "adjustments" to white balance, exposure, contrast, clarity, sharpening, and removal of digital noise - the same sort of things done to create a JPEG file in the camera but without compression of the file and loss of data. Digital cameras automatically capture the EXIF information for each image - this includes date, time, camera, lens, shutter speed, aperture, ISO, flash, copyright, and other information embedded into the image file.

After import and screening for 'bad' images, I view every image for 'first round' processing. I straighten the image and crop it if necessary. Next, I recheck the white balance and adjust the exposure and contrast to assure there is no 'clipping' of the whites or blacks that cause loss of clarity or detail in the image. Next, I add more specific keyword tags to selected images and if needed apply fine detail exposure and contrast enhancements to make the image 'come to life" more realistically as I saw it.  Finally, I geo-tag the approximate location of the shot on Google Earth and back-up the files on the computer and re-format the memory card in the camera for the next day's shooting. 

I put the images out of mind for a day or two and then revisit the image folder for the day to compare and eliminate duplicate (or near duplicate) images. I may refine the keyword tags and grade the images from one to five stars (still no 4 or 5-star images!) The starred images may receive additional cropping, exposure, or sharpening adjustments. Finally, a few images will go to Photoshop for advanced editing to remove artifacts or stitch together panoramas or high dynamic range images.

So there you have it, a lot of steps but much of the process is automated.  The result is searchable, unique, refined images that are ready for conversion to JPEGs for sharing or printing. I will expand much of the post-processing information in later posts. But now it is time to start shooting again.

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How to ruin a picture quickly

Failure is the key to success - or - mistakes are the best way to learn! In the last posting I revealed my failure rate was about 44% of all shots I take and only about 7% of my shots do I really like. So what goes wrong when capturing an image and why do I really care?

Photography is a learned technical skill.  Learned by reading, classroom work, watching videos, research on the web but, photography is really learned by trial and error. Taking pictures and critically reviewing them in a timely fashion is the best way to improve your photographic skills - taking lots and lots of photos! In the tremendous book "Outliers," Malcom Gladwell claims that to really master a complex task it takes the average person about 10,000 repetitions. Photography is a complex task, certainly made easier with automated digital cameras, but none the less complicated. Automatic digital cameras (and, even iPhones) reliably take good snapshots and, occasionally, even good photographs. However, at some point in time, aspiring photographers will make the move from a point-and-shoot to a dSLR (digital single lens reflex) camera. The move allows for greater creativity but also many more ways to foul up a good picture.

So how are images destroyed at the time they are captured?

1) Bad focus always ruins a photo. Most digital cameras have an auto-focus system that is capable of many modes of focus. Auto-focus is attained when the shutter button is displaced halfway. Focus points show in the viewfinder and the operator has a choice of which point or points to select. When focus is attained there is usually a beep or a visual indicator of the selected focus point. Given multiple possible focus points in a scene, the camera will select the closest one - maybe not the one of greatest interest. Because of this problem, most nature photographers choose the "spot focus" mode so only one point is chosen by the camera. The subject of greatest interest is centered on this point and the shutter button depressed halfway down. Then the shot can be properly composed and the shutter fully depressed to expose the image. Obviously there are a lot of ways this can go bad and an out of focus subject ruins the image. No degree of post-processing (editing) can fix the image.  When precise focus is critical many choose to use manual focus either through the viewfinder or in the "live view" mode on the LCD. The advantage of this mode is that the image can be magnified greatly during the focus process for precise control. This,of course, requires a tripod and a very stationary subject.

2) Similar to bad focus, motion blur also can  ruin an image. Blur is different from out of focus. When a subject is out of focus there is usually some portion of the image that is in sharp focus. With motion blur, usually nothing is in focus if the camera moved during the exposure. If the subject moved, obviously it can be the only thing in the image that is blurred. The most common cause of blur in my experience is "camera shake." Camera shake is induce by poor technique in holding the camera or pressing the shutter release button. It is magnified by long exposure times and telephoto lenses trying to capture a distant or small subject. The result is a "soft" image or one that lacks crisp detail.  In addition to poor technique, camera shake can be induced by the vibration created when the mirror retracts as the shutter opens. Good camera hold technique and careful release of the shutter help but on long telephoto shots vibrations need to be minimized. Four things minimize shutter release and mirror vibration: 1) a sturdy tripod to hold the lens still, 2) a cable or remote shutter release, 3) locking up the mirror prior to exposure, and 4) fast shutter speed. 

3) Bad composition is a sure way to ruin an image. Taking time to consider all compositional elements before capturing the image is key but also shooting the scene from several perspectives improves the chance you will have a good composition. Professional photographers always tell you to "work the shot."  This means moving to several different camera locations, changing perspective from normal to high or low, using different focal lengths or zooming the lens, changing the depth of field, and shooting in vertical (portrait) and horizontal (landscape) formats. All of these things can help to create the best composition. Composition may be the hardest thing to learn in all of photography.  Poor composition is not necessarily the end of a digital image. Post-processing by cropping can sometimes save a poorly composed image but cropping deletes pixels from the image and will lower the resolution of the final print.

4) Serious exposure errors can reduce a great, well-composed, sharply focused image to a throw away. Exposure is fairly complicated and requires appropriate balance of the three elements of the "exposure triangle" - shutter speed, aperture, and ISO. In the automatic or program modes of the camera, these three factors are balanced for you. However, auto and program modes severely limit your creative ability and may reduce good shots to snapshots. I will spend time in a later posting discussing why and how you might want to have control over the exposure triangle but for now let's agree that good exposure is necessary for a good photograph. Fortunately for all of us, post-processing can often repair minor exposure errors. Underexposed (dark) images are more easily repaired than overexposed(light) images.

5) The last element that destroys the impact of your photographs on the viewer is what I call lack of emotion.  Flat, dull, washed-out colors in a bright scene have no emotional impact on the viewer.  Photographers often refer to this as "punch." I almost always like punchy photographs - bright vibrant, saturated color that depicts nature at her best. I strive to produce these in my wildlife shots, macros, and wildflowers. Sometimes emotion is better conveyed in low contrast, moody shots. I love an early morning shot in the rising fog. Good exposure is the first step in creating mood and emotion in a photograph but post-processing also is a big part of bringing drama to a good shot.  

So that is it - 5 ways to ruin a photograph or, 5 things to remember when shooting to make your shots better. I will come back to each of these issues in future posts.

As always, please post your comments and contribute to this blog. There are several outstanding professionals on the contacts list who can add insight and perspective to these thoughts. 

Posted on

How to ruin a picture quickly

Failure is the key to success - or - mistakes are the best way to learn! In the last posting I revealed my failure rate was about 44% of all shots I take and only about 7% of my shots do I really like. So what goes wrong when capturing an image and why do I really care?

Photography is a learned technical skill.  Learned by reading, classroom work, watching videos, research on the web but, photography is really learned by trial and error. Taking pictures and critically reviewing them in a timely fashion is the best way to improve your photographic skills - taking lots and lots of photos! In the tremendous book "Outliers," Malcom Gladwell claims that to really master a complex task it takes the average person about 10,000 repetitions. Photography is a complex task, certainly made easier with automated digital cameras, but none the less complicated. Automatic digital cameras (and, even iPhones) reliably take good snapshots and, occasionally, even good photographs. However, at some point in time, aspiring photographers will make the move from a point-and-shoot to a dSLR (digital single lens reflex) camera. The move allows for greater creativity but also many more ways to foul up a good picture.

So how are images destroyed at the time they are captured?

1) Bad focus always ruins a photo. Most digital cameras have an auto-focus system that is capable of many modes of focus. Auto-focus is attained when the shutter button is displaced halfway. Focus points show in the viewfinder and the operator has a choice of which point or points to select. When focus is attained there is usually a beep or a visual indicator of the selected focus point. Given multiple possible focus points in a scene, the camera will select the closest one - maybe not the one of greatest interest. Because of this problem, most nature photographers choose the "spot focus" mode so only one point is chosen by the camera. The subject of greatest interest is centered on this point and the shutter button depressed halfway down. Then the shot can be properly composed and the shutter fully depressed to expose the image. Obviously there are a lot of ways this can go bad and an out of focus subject ruins the image. No degree of post-processing (editing) can fix the image.  When precise focus is critical many choose to use manual focus either through the viewfinder or in the "live view" mode on the LCD. The advantage of this mode is that the image can be magnified greatly during the focus process for precise control. This,of course, requires a tripod and a very stationary subject.

2) Similar to bad focus, motion blur also can  ruin an image. Blur is different from out of focus. When a subject is out of focus there is usually some portion of the image that is in sharp focus. With motion blur, usually nothing is in focus if the camera moved during the exposure. If the subject moved, obviously it can be the only thing in the image that is blurred. The most common cause of blur in my experience is "camera shake." Camera shake is induce by poor technique in holding the camera or pressing the shutter release button. It is magnified by long exposure times and telephoto lenses trying to capture a distant or small subject. The result is a "soft" image or one that lacks crisp detail.  In addition to poor technique, camera shake can be induced by the vibration created when the mirror retracts as the shutter opens. Good camera hold technique and careful release of the shutter help but on long telephoto shots vibrations need to be minimized. Four things minimize shutter release and mirror vibration: 1) a sturdy tripod to hold the lens still, 2) a cable or remote shutter release, 3) locking up the mirror prior to exposure, and 4) fast shutter speed. 

3) Bad composition is a sure way to ruin an image. Taking time to consider all compositional elements before capturing the image is key but also shooting the scene from several perspectives improves the chance you will have a good composition. Professional photographers always tell you to "work the shot."  This means moving to several different camera locations, changing perspective from normal to high or low, using different focal lengths or zooming the lens, changing the depth of field, and shooting in vertical (portrait) and horizontal (landscape) formats. All of these things can help to create the best composition. Composition may be the hardest thing to learn in all of photography.  Poor composition is not necessarily the end of a digital image. Post-processing by cropping can sometimes save a poorly composed image but cropping deletes pixels from the image and will lower the resolution of the final print.

4) Serious exposure errors can reduce a great, well-composed, sharply focused image to a throw away. Exposure is fairly complicated and requires appropriate balance of the three elements of the "exposure triangle" - shutter speed, aperture, and ISO. In the automatic or program modes of the camera, these three factors are balanced for you. However, auto and program modes severely limit your creative ability and may reduce good shots to snapshots. I will spend time in a later posting discussing why and how you might want to have control over the exposure triangle but for now let's agree that good exposure is necessary for a good photograph. Fortunately for all of us, post-processing can often repair minor exposure errors. Underexposed (dark) images are more easily repaired than overexposed(light) images.

5) The last element that destroys the impact of your photographs on the viewer is what I call lack of emotion.  Flat, dull, washed-out colors in a bright scene have no emotional impact on the viewer.  Photographers often refer to this as "punch." I almost always like punchy photographs - bright vibrant, saturated color that depicts nature at her best. I strive to produce these in my wildlife shots, macros, and wildflowers. Sometimes emotion is better conveyed in low contrast, moody shots. I love an early morning shot in the rising fog. Good exposure is the first step in creating mood and emotion in a photograph but post-processing also is a big part of bringing drama to a good shot.  

So that is it - 5 ways to ruin a photograph or, 5 things to remember when shooting to make your shots better. I will come back to each of these issues in future posts.

As always, please post your comments and contribute to this blog. There are several outstanding professionals on the contacts list who can add insight and perspective to these thoughts. 

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