What does that and curiosity have to do with contemporary digital photography? Well, my last post elicited a reaction from one reader asking why in my discussion of digital image quality I did not mention acuity, resolving power what most refer to as sharpness. And for that matter, neither did two of the authors with articles on lenses in the August issue of Shutterbug mention image sharpness. I did write about it at least indirectly several years ago when the first 18-55mm “kit” lenses for APS-C dSLR cameras appeared. The first one of these $100 lenses I had in my hands I tested on a new dSLR camera body against a $1,000 top rated pro lens covering roughly the same range of focal lengths. Although a 10X differential in cost the two lenses produced virtually pixel for pixel identical images. The “kit” lens produced an image just as sharp and detailed as the $1.000 pro lens. However, I don’t think anyone believed me or took my test seriously.
Part of the reason for that is many Shutterbug readers still think in an analog film mindset even though they may be using digital. The other reason is something I learned beginning over 30 years ago writing for photo enthusiasts: few photographers read the manual or published guide that comes with a new camera, at least beyond finding which buttons to push to make the camera take a picture. Very young children are inherently curious, as soon as they learn to speak the word they use the most is WHY. But that inclination seems to lessen to almost nil as the years pile up for most people. I am apparently an odd ball. As soon as I get something new and different I want to know and understand how it works, and I am not comfortable until my curiosity is satisfied.
So, what should one find in a new camera user guide/manual booklet that will provide a better understanding of how a digital camera actually works? It was 2-3 years ago that I purchased the personal camera I now use, but when I got it and unpacked the box one of the first things I did after putting in a battery and putting the camera on a table in front of me for reference, was crack the user guide manual. My first curiosity was what controls are there to use to adjust this camera to make it do what I intend. Those answers I found in a section called Image Settings. There I found that the camera’s LCD screen menu contained selections that allowed me to choose different camera settings for a variety of subjects and kinds of picture making operations. One was named “standard” and was recommended as the general all-purpose setting to obtain vivid, sharp images, and the setting intended for use when the camera is used in full automatic mode. The next optional setting named was “portrait”, and obviously self-explanatory for a somewhat softer, and flattering to skin tones image response. Then the next setting option was “landscape”, again somewhat self explanatory, to produce very vivid color and sharp images of scenic subjects. Then there is a setting without reference to any particular subject called “neutral”, that does not enhance any picture characteristic value and does not sharpen the image. And there is another similar setting called “faithful” that is also neutral but involves a set color temperature (white balance) and colorimetric image adjustment to match the subject color, and again without any sharpening. In addition to these described settings, each has an adjustment scale to customize image capture performance, to add or subtract values on a numbered scale for sharpness, contrast, color saturation, and color tone (balance/hue). And finally, for the subject settings, standard, portrait and landscape, there are specific manufacturer specified default value number settings for sharpness (only).
From this information I could make some logical assumptions. That even set to save images in Raw format the camera uses internal processing to adjust the information collected by the image sensor, so in any of the Settings, standard, portrait and landscape, the Raw file is adjusted and is not limited to what the sensor captures. To obtain a Raw file that is limited to what the censor captures as true to the subject as possible the “faithful” setting must be chosen. And from what the guide/manual describes, unless neutral or faithful setting are chosen the camera’s processing applies a considerable amount of sharpening to all image files.
Even after gleaning as much useful information as possible from the user’s manual, I remained full of curiosity. The only way to satisfy my need to understand was to run a series of tests with the camera which would provide a set of photographic images using all of the options in Image Settings so I could compare one with another as photographs, visually. So, I made a charts which identified every setting and variation of settings with different sharpness, contrast and saturation value choices. With this chart in hand I put the camera on a tripod and chose an area as a subject with both vivid and subtle coloration, light and darks, shadows and highlights, as well as smooth areas and fine lines and detail. Locked down on my tripod and focused on this subject I made a series of exposures with each of the settings and variations recording the frame number on the chart so I could associate each exposure frame with each setting choice once all of the Raw files were processed.
This was of course a lengthy and tedious process, but once the files were all done and available for viewing using Adobe Bridge I could put the default standard image up and open another next to it for visual comparison. All of the subject settings like standard, portrait and landscape had image quality attributes consistent with what the user guide description led one to expect. Then if the sharpness setting or the saturation setting was increased or lowered the image reflected a moderate expected difference. But then comparing the default standard exposure frame with either the neutral or faithful default setting frame revealed a very different picture of the subject, no real image sharpness at all to the extent some of the fine detail in the subject was not even visible, and contrast was very much flattened, as well as little saturation, a virtually pastel image. Finally, I opened the default faithful image file in Photoshop to see how much adjustment was needed to color correct the image to match the image made with the default standard setting. The amounts of sharpening (using not just one but most of Photoshops sharpening tools), increases in contrast and saturation were all very large adjustments to get the attributes of the faithful image setting file close to matching the standard in basic photographic image attributes we call quality
.To be candid I was surprised by this test experience. From the documentation of the camera companies who laud the finished in-camera processing when you set output to JPEG, and their suggestion that when you choose to output in Raw format the image file is just what comes off the image sensor, is definitely not the case. Even saving in Raw the camera using “normal” image settings enhances all of the basic image attributes, particularly sharpness, as well as contrast and saturation.
Recently, I came back to this after “the Kodachrome look” became a topic of reader interest, and some third party “filters” to apply this Kodachrome look came out. So, I wondered if I created a new “custom” setting in the camera, adjusting sharpness, contrast, saturation and color tone if I could make my camera output files that mimic the Kodachrome look. Yup, no sweat after a bit of experimenting and tweaking the settings adjustments.
If you have a comment, they are welcome, so please post it. If you have a question you want me to answer please address an e-mail to David B. Brooks at: firstname.lastname@example.org