RogerNorton

• Name: Roger Norton, LRPS
• Email: roger@lenscap.nortonrl.plus.com
• Phone Number:
• Web Page: Roger Norton Photography

• Country:
• Town:
• Comment: Centre Coordinator, RPS Digital Imaging Group - Thames Valley

Remove the lens cap to see the real e-mail address!

My interest in photography dates back to my early teens when I was producing black and white images in my father's darkroom. My father was a keen amateur photographer and he was, and remains, my inspiration. I set up my own colour darkroom in the 1980s and converted to digital photography in the 1990s. I invested in my first DSLR, a Canon EOS 300D, some years later. I now use a Canon EOS 5D Mk II which far outperforms my expectations. I am also an Apple Mac convert and now wonder why I ever bothered with PCs! If I'm really honest, though, you can get fantastic results from entry level DSLRs and many compacts. And Macs, like PCs, are just tools and it matters not which you use. The biggest variable in digital photography is the same as in film-based photography - it's the guy that presses the button!

If you would like to see some of my pictures, please have a look at my new website, ON-LINE AS OF 29 June 2009

SUGGESTED RAW WORKFLOW (Reference Club Lecture "Digital Myths", 21st September 2010)

This detailed workflow was discussed at the Club meeting on 21st September 2010 in my talk “Digital Myths”. It is based on information gained at a lecture by Guy Gowan (www.guygowan.com). The workflow contradicts much of the 'accepted wisdom', but I believe that it is logical and, moreover, it works for me.

The words of the late Bruce Fraser (a highly-regarded Photoshop guru) confirm that this is the correct approach:

“You may be tempted to underexpose images to avoid blowing out the highlights, but if you do, you’re wasting a lot of the bits the camera can capture, and you’re running a significant risk of introducing noise in the midtones and shadows. If you underexpose in an attempt to hold high-light detail, and then find that you have to open up the shadows in the raw conversion, you have to spread those 64 levels in the darkest stop over a wider tonal range, which exaggerates noise and invites posterization”.

Step 1 – Exposure This is quite unlike exposing for jpeg images when it is necessary to “expose to the right” to ensure detail in the highlights. In this case, the exposure is adjusted by setting the exposure override to a negative value, say -0.5 to -1.0 stops, or more.

When shooting in raw format, exposure should be correct for the mid-to dark-tones. This is not an easy concept but it can be learnt with experience. Sometimes camera metering seems to get it about right. Other times, usually in a scene with high contrast, the shadow areas are too dark. This is corrected by setting exposure override using a positive value (say, +0.3 to +0.6). Alternatively, you can spot meter from an area of mid-tone. The aim is that the shadows and darker tones are correctly exposed and need little or no correction in Adobe Camera Raw (ACR). Do not be concerned that the highlights appear burnt-out and bear in mind that histogram is the camera's interpretation of what the jpeg image would look like. Personally, I tend to place little reliance the camera histogram when shooting raw images.

Step 2 – Raw conversion: pulling in the highlights Firstly, it is essential that your monitor is correctly calibrated and brightness is properly set up. You should be able to differentiate all 21 steps in the test file below. My Mac monitor is calibrated to 100 lumens and some say that this could be too high and suggest 80 lumens.

When you open the image in ACR (or your favoured raw processing software), you should find that the exposure in the darker mid tones and mid tones looks about right. It is highly likely that the highlights appear to be burnt-out. The first step is to move the exposure slider to the left until detail is revealed in the “burnt-out” areas. You can use the alt or option key at the same time to get a visual clue that the highlights have been recovered but this can give over-correction and a false look. Make sure that you do not try to get detail into specular highlights (e.g. reflections from rippling water). If necessary, you can also apply modest changes to the recovery slider.

Figure 1: Histogram of unadjusted raw file

Figure 2: Histogram of raw file with exposure adjusted to 1.7 stops in ACR

The side effect of these changes will be that the image is now generally much darker. However, you will find that there is little or no scope to adjust the Blacks slider to remedy this. This is best done in Photoshop (or equivalent software). If desired, you may adjust either or both of the clarity and vibrance sliders before opening the image in Photoshop, Photoshop Elements, or whatever.

Step 3 – Lightening the shadow areas There are several ways in which this can be done. I recommend either using the shadows/highlight control or a contrast mask. The former method is the easiest, but I prefer the second.

3.1 Shadows/Highlights Adjustment

Image > Adjustments > Shadows/Highlights . . . Adjust the shadows until the dark to mid-tones look correct. Ignore the highlight controls.

3.2 Contrast Masking

This is my preferred method. As there are a relatively large number of steps, it is best run as an action (see below) as follows: Create a duplicate image and label it “Contrast Mask”. Select Image > Mode > Greyscale. Select Filter > Blur > Gaussian Blur and set to about 5 pixels. Now return to the original image and choose Select > Load Selection using the image named “Contrast Mask”; select the box labelled invert. Select Edit > Fill and set “Use” to 50% grey, “Blending” to Color Dodge, and “Opacity to 100%. Select Edit > Fade fill to adjust the intensity of the effect if required. Go to select > deselect and save the image. Discard the duplicate image named “Contrast mask”.

Downloads:

You can download a copy of the above action here:

• Rogers_actions.atn: Contrast mask action

Right-click on the file and choose "save as" (Windows), or CTRL-click (Mac) and choose an appropriate destination. Load the action will run into the Actions Palette in Photoshop. If you wish to use it in Photoshop Elements, you should follow the advice in http://graphicssoft.about.com/od/pselements/qt/actions.htm

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