ESFotoClix Blog

If like me, you don’t have that Ansel Adams knack for visualizing an image in gray tones, perhaps the following tips will help you figure out how your photographs can work as Black and White (B&W) images. First, if you want to receive immediate feedback as to what your image will look like, shoot monochrome. This may be a paradigm shift for you because the experts have told you to capture in color, then convert to B&W in post-processing. The myth, left over from the days before you had a competent DSLR, is that capturing directly into B&W is an irreversible process. Not so if you capture RAW images.

When you do this, avoid if you can the blah grayscale option. Instead apply color filtering to your B&W capture. Here’s what I do with either of my DSLRs (Nikon D80 and D90). I go into the Picture Mode (D80) or Picture Control (D90) menu and select the monochrome option and enable a color filter. Which color you use is up to you, but I find red, orange and yellow to give me the best results for most situations, and I use green occasionally. When you select one of these color filters, this is somewhat equivalent to attaching a physical color filter of the same color without having to worry about having the right diameter for your particular lens. Nifty, but keep in mind that it’s not perfect. Think of it as an approximation to give you a rough idea of how a B&W capture will work out.

Nikon D80 Monochrome filters

Nikon D90 Monochrome filters

Make sure you set the camera’s capture format to RAW, and later, if you repent from having chosen B&W, or if you want to try a different filtering technique, you can switch back to color. With Nikon RAW files (NEF), ViewNX will let you swap Picture Controls to revert back to color. Whether you do this or capture your original image in color, this brings us to our next option for generating B&W images with pop to them.

Bring your color image into your editor of choice, make any adjustments you want to make to color, white balance, sharpness, or whatever else you want to modify, and then bring up your application’s color filtering tool — again avoid the grayscale conversion. In Paintshop Pro X2 (PSPX2), this interface presents you with a color wheel, as shown below, that lets you set any color filtering you want. You can start to see the additional flexibility in this approach: you can have a plethora of shades of yellow or green or cyan (try finding that filter at your camera store) or anything in between, allowing you to tweak the output exactly as you want it.

To demonstrate how this works, let’s review a couple of images from yesterday’s discussion.

B&W, as shot in-camera	Color, reverted from RAW in ViewNX with White balance correction
B&W conversion with color filtering in PSPX2	Result from B&W conversion (including contrast and sharpening)
B&W, as shot in-camera	Color, reverted from RAW in ViewNX with White balance correction
B&W conversion with color filtering in PSPX2	Result from B&W conversion (including contrast and sharpening)

As you can see, applying color filtering for B&W conversion in post-processing gives the greatest flexibility and enables you to improve monochrome output quality. My recommended approach is to shoot RAW with a Monochrome filter in the field to preview whether a shot works as B&W on the spot, i.e., as an aid to visualization, then go home and tweak away in post-processing to optimize and maximize the quality of the final image.

One word of caution with this approach: it just so happens that the filters I like best, red and orange, tend to reveal more noise in blue skies. Green filters, on the other hand, produce the least noise. We could get technical here about Bayer sensors containing a majority of green pixels which when excluded with red or orange filtering leaves us with a noisy image. But instead I’ll just recommend that you experiment to see how this approach works for you.

After making some disparaging remarks about Active D-Lighting (ADL), the data caused me to reconsider. Primarily, I now see I had the wrong expectations.

How I thought ADL worked: I thought ADL would auto-magically compensate for Matrix metering’s (MM) tendency to over-expose. Indeed, in some test cases I saw how ADL applies negative compensation, but not enough to make a difference consistently.

How ADL seems to do best: If you apply negative compensation to MM or otherwise meter to avoid clipped highlights, ADL helps avoid under-exposed shadows through adjustment of the tone curve (or however it does it), effectively pushing out shadow detail and producing a balanced shot.

To elaborate, I assumed that ADL would adjust MM’s tendency to over-expose, much in the same way I sometimes purposefully expose to the right by +0.3 to +0.7EV from what the Spot meter indicates as the centered exposure, then back-off the exposure in ViewNX and apply shadow protection to recover shadow detail. Why I thought ADL would do something similar I can’t really explain, but to move on and learn something new let’s compare some samples of my approach vs. ADL and see which does better. Along the way, we will examine the effect each approach has on noise, and to illustrate the effects of each of the approaches, we will use ISO800.

The first capture uses Matrix metering with ADL=OFF. The bright back-lighting against our dark subject produces the typical Matrix metering clipping in the highlights.

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For the next capture we set ADL to Normal. ADL tames down the highlights a bit, but not enough, and pushes out shadow detail in the vase. Start paying attention at the 100% crop on the right and look at whether noise is becoming more evident there.

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For the next two exposures, we use -0.7EV and -1.0EV respectivealy. Now the highlights are under control, but what is happening in the noise department?

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To arrive at this final image we use the first exposure, thankfully captured in RAW, and we apply -0.7EV adjustment in ViewNX and shadow protection = 30. (For another example of this technique, see When Over-exposure happens). Compare the resulting image to the previous 4 samples.

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Which adjusted exposure achieves the best noise performance should be self-evident. Which of these achieves a better balance in the overall exposure is probably largely a matter of preference. My perspective is that the last image balances highlights, middle tones and shadows best. I wish ADL or some other algorithm performed similar simple adjustments on the fly in-camera (hint, hint, Nikon).

In response to my Active D-Lighting (ADL) experiments, some have recommended I try ADL with Matrix metering (MM) while applying negative exposure compensation (EC). The suggestion was to use -1 EV, with the idea that this would avoid blown highlights and ADL would compensate through shadow recovery. This makes sense and promises to solve the problem with possible under-exposure that would occur if one were to address Matrix metering’s tendency to over-expose by applying across-the-board negative compensation.

I decided to give this a go with the following five captures using ISO 200, aperture=f/8 in Aperture priority mode.

EC=0 and ADL=off gives an exposure at 1/13sec. An examination of the histogram will show clipping in the reds.
EC=-1EV and ADL=off gives an exposure at 1/25sec. All highlights are well-contained, but the shadows are a bit on the dark side. Time to call ADL to the rescue.
EC=-1EV and ADL=Normal result in an exposure at 1/30sec. The shadows are recovered, and the highlights are well balanced as well.
EC=-1EV and ADL=High yield and exposure of 1/40sec, with subtle further boosting of the shadows while maintaining well-contained highlights.
EC=-1EV and ADL=Extra High also give a 1/40sec exposure, with subtle further boosting of the shadows while maintaining well-contained highlights.

Looks great, right? Well, pay attention to those shutter speeds. Even though there’s no clipping whatsoever with ADL=OFF and -1EV of compensation, ADL=Normal further under-exposes by an additional 0.3EV, and for ADL High & Extra High ADL under-exposes by 0.7EV. We can only imagine what that will do at higher ISO values. Noise will come on like gangbusters. The recommended mitigation would be to stick with lower ISO’s, though this may not always be practical.

Let’s not completely ignore these results, however. If the situation is one where we have plenty of lighting so that keeping the ISO low is possible (i.e., we’re not capturing fast action), and you want to use Matrix metering with negative compensation, ADL may indeed help balance the exposure to avoid under-exposure, especially in shadow areas.

~O~
Addendum: To further illustrate how ADL behaves with under/over-exposure, first we used Spot metering in Manual mode to determine a middle-tone exposure somewhere between 1/25sec and 1/30sec, and bracketed 8 images around this middle-tone value with ADL=off stepping exposure in 1/3 EV increments, from 1/10sec to 1/50sec. Then we switched to MM, turned ADL to High and repeated. Side-by-side comparisons are shown in the following table.

Manual Exposure	Spot, ADL=OFF	MM, ADL=High
ISO 200, f/8, 1/10sec
ISO 200, f/8, 1/13sec
ISO 200, f/8, 1/15sec
ISO 200, f/8, 1/20sec
ISO 200, f/8, 1/25sec
ISO 200, f/8, 1/30sec
ISO 200, f/8, 1/40sec
ISO 200, f/8, 1/50sec

Looking at this last set of samples, it appears ADL does much better when one negatively compensates MM. As previous samples show, when MM over-exposes the highlights by a fair amount (+0.7 to 1.0EV), ADL’s negative compensation may be insufficient to “rescue” the highlights. But if you apply negative compensation or spot-meter in Manual mode to set a middle-tone exposure, then switch back to MM, ADL is in a much better place to adjust the tone curve and achieve a more balanced look to the image. A workable strategy for harsh lighting situations may be:

1. Spot-meter against a middle-tone (approximating middle gray)
2. Manually set exposure to that value (or lock it in a non-Manual mode)
3. Switch to MM and set ADL on (normal or high)
4. Snap away.