By Carl Weese
Last time we looked at some test results working with RAW files. Of course not everyone likes to work with RAW. The K10D offered two flavors of JPEG: Natural, and Bright. While not quite Baskin Robbins yet, the K20D has expanded the line of JPEG flavor offerings considerably. These are accessed from the Function button (not the general menu) and include: Bright, Natural, Portrait, Landscape, Vibrant, and Monochrome. Mono lets you select modes that mimic filter effects: None, Green, Yellow, Orange, Red, Magenta, Blue, Cyan, Infrared Color. You can punch in warmer or cooler toning of the monochrome image and customize contrast and sharpening.
In each of the color modes you can alter the starting point and punch in your own changes to Saturation, Hue, Contrast, and Sharpness. The various modes are in themselves simply pre-set suites of these settings. Natural looks good to me, especially if the Contrast setting is backed off one or two clicks. In fact that looks very close to the ACR 4.4.1 interpretation of the RAW file on my defaults (which use slightly lower black point and contrast settings than Adobe’s defaults). If I need to shoot RAW+JPEG in order to have immediate access to non-RAW files, that’s the setting I will use. All of the others are variations on the theme of “how I don’t want my pictures to look.” Hyped-up candy-apple color. To someone else of course these may be nice bright colors that look just right.
Going back to that white-clipping test on the RAW files, the Natural JPEG mode will mimic the results of that test, but without the benefit of ACR’s Recovery function. That is, there should be full detail through 2.3 stops above the middle, but then clipping will set in and be quite severe at +2.7. So these JPEGs will have less retention of highlight, less reach into the high values than RAW files even on default. The Pentax Photo Lab software will observe these settings in presenting you a default view of a RAW file, but of course since it is RAW you can make any changes you want; the camera settings serve only as a starting point. The other JPEG flavors will reduce the tonal range even more—this is the tradeoff for the questionable benefit of snappier contrast and higher saturation. Happily, none of these settings have any permanent effect on the RAW files, so if you want to play with these controls I recommend setting the camera to RAW+. I admit I’m curious to see what happens with the monochrome settings and will report when I’ve had a chance to play.
Here’s a really novel feature that I’m only going to describe briefly because it would take a lot of testing and experience to get a handle on it. The K20D offers “expanded dynamic range.” What’s that, you say? Let’s look in the manual: “By using the Expand Dynamic Range function, you can expand the light level expressed by the CMOS sensor pixels, making it more difficult for bright areas to occur in the image.”
To turn it on, you go to the ISO settings through the function button, then hit the function button again to toggle from normal to “D-Range 200%.” When you do, ISO settings below 200 become unavailable. JPEGs shot with d-range on show a big increase in ability to hold apparent highlight information. I say apparent because, while there’s an enormous increase in how far up you can expose without clipping (farther than a RAW file on defaults) there’s something funny about the color information. Like using a massive amount of Recovery in ACR, this appears to be extrapolated rather than direct data. Another serendipitous accident: when I first ran a highlight test with d-range on, I neglected to reset a manual WB setting from a previous test. This resulted in a slightly yellow color in the test run. The normal JPEG files showed this warm bias from mid value up to +2.3, above which they clipped. The d-range JPEGs held off clipping all the way to +3.7, but the color had lost its yellow cast, gone nearly neutral, by +2.
Pictures of actual subjects consistently show an effect on JPEG files from the d-range feature, but the effect varies greatly depending on the subject and brightness range of the scene. In high contrast situations like backlight or harsh cross-lighting, the feature can give a dramatic improvement. On more normal subjects it can sometimes give a strange HDR-like appearance. Mid-tones are generally raised, but shadows are almost completely unaffected. In many cases the blending effect reduces color saturation. If you want to play a real game of concentration, you could try testing those jazzier JPEG flavors like Bright and Vibrant combined with d-range.
Here's the clutter next to my imaging computer, harshly lit by a desk lamp. The histogram from a JPEG shot on Natural shows clipping of the highlights (this low rez view hides how high the right side of the histogram goes up the wall).
The 72 ppi sRGB screen grab of a shot at the same settings but with d-range turned on probably won't show much improvement on your monitor, but look at that histogram. There is a major improvement in the highlights and upper middle tones, though no real change in the shadows.
Here’s what I think is going on. They call it 200%, and you lose the first stop of normal sensor ISO range. I think the camera is doing a form of HDR on the fly, combining the basic data of a shot at ISO 200 (for example) with the highlight detail that would have been captured at ISO 100. The effect is tricky. It’s quite difficult to get exactly the same look by adjusting a RAW file in ACR, although it’s easy to get a similar, just-as-good-or-better result. For anyone who has to shoot JPEG files it would be a good idea to get a handle on this feature because the improvements in some situations are very real. But I don’t think it should be used as a “set it and forget” default option. One last point on d-range: unlike all the other picture flavors offered by the K20D, this one affects RAW files. Not anywhere near as much as JPEGs, but RAW files shot with the feature turned on hold a little more highlight detail than with it off. You can avoid clipping at +3.3 with less, almost no, Recovery. The effect is even slightly different for PEF and native DNG captures. So it looks as though both the sensor and the JPEG engine are participating in this game.
Now on to some reactions to actual picture taking with the K20D. The first thing I noticed examining folders of files in Bridge was that the camera’s automatic white balance has gotten a whole lot smarter. Accurate AWB is vital for shooting JPEGs since substantial color correction of an 8-bit file is bound to cause quality losses. With RAW a bad AWB just forces you to fix it, there’s no loss of quality (an exception is if you were setting your exposure using a tri-color histogram and the WB was so far off that, once corrected, you get clipping in a channel that was unclipped at the wrong WB). But it’s nice to open a folder and see a slew of consistent captures without spending the first part of a work session changing the temp/tint settings of every other exposure. While on this, a nice touch is that the camera lets you fine-tune the AWB. The default setting was too green and too warm for my taste, but through the function button it was easy to open a color box and move the hot spot left and down to adjust the color to my preference. ACR tracks this change and shows the adjusted color as long as WB is left at the default “as shot.”
(Auto white balance, auto (program) exposure on multi-segment metering, DNG on the defaults in ACR run through my usual web-posting batch action.)
The next thing I noticed was that the multi-segment pattern metering also seems to have had its IQ raised. Exposure compensation is needed less often, and when needed, you don’t have to use as much. I’m actually having to re-train myself to dial in less compensation with the new camera. Of course the fact that there is a bit more overall dynamic range than offered by the K10D may be helping the meter by giving it a broader target to hit.
Next installment will be after I’ve had a chance to do a lot more actual picture taking.