"Sunlit" Portrait:
(This is my new "Outdoor" Portrait test - read more about it here.)

High resolution, but a slight red cast and high contrast, and some softness due to anti-noise processing.

The extreme tonal range of this image makes it a tough shot for many digicams, which is precisely why I set it up this way, and why I shoot it with no fill flash or reflector to open the shadows. The object is to hold both highlight and shadow detail without producing a "flat" picture with muddy colors, and the DX7590 Zoom did a pretty good job with it.

The shot at right was taken with a +0.3 EV exposure compensation adjustment, produced reasonable midtone values, but left the highlights a little blown-out looking. The shot with no exposure compensation held onto the highlights in Marti's shirt and on her face, but left the whole image a bit too dark-looking. I chose the Auto white balance setting for the main series, as the Daylight setting had a stronger red cast.

Marti's skin tones are slightly reddish (as is overall color), and the blue flowers in the bouquet are darker and a bit more purple than in real life. (Many digicams have trouble with this blue, which is in reality a light navy with just hints of purple.) The bright yellows and greens look very good, but the red flowers are somewhat hot and oversaturated. Resolution is very high, with a lot of fine detail visible in the flower bouquet, and a fair amount in Marti's face, but the camera's anti-noise processing softens detail somewhat across the image. Shadow detail is moderate, and image noise there is low.

To view the entire exposure series from -0.3 to +0.7 EV, see files 759OUTAM1.HTM through 759OUTAP2.HTM on the thumbnail index page.

Excellent resolution and detail, though again high contrast.

In this close-up shot, overall color is still slightly reddish with the Auto white balance, though it appears to have cooled slightly from the wider shot above. The shot at right was taken with an exposure compensation of -0.3 EV, which produced good midtones and tamed the highlights on Marti's face, but at the cost of very dark shadows. The DX7590 Zoom's impressive 10x zoom lens helps prevent any geometric distortion of Marti's features, and captures minute detail. Resolution and detail are much stronger in this shot, with great definition in Marti's face and hair, as well as in the fabric of the leaf. (At this larger scale, the operation of the 7590's anti-noise image processing is less apparent.)

To view the entire exposure series from -0.3 to +0.7 EV, see files 759FACAM1.HTM through 759FACAP2.HTM on the thumbnail index page.

Normal Flash +0.7 EV

Night Portrait Mode

Low intensity at the default exposure, and a pink color cast.

The DX7590 Zoom's built-in flash underexposed somewhat at the default exposure setting (a fairly common occurrence with digicams on this shot), though coverage is fairly even on Marti. I found the best exposure with a +0.7 EV exposure compensation adjustment, which actually left the white shirt a little hot, but produced a good exposure elsewhere. Overall color is pinkish, with a slight orange cast on the back wall and in Marti's hair from the background incandescent lighting. Still, the flower bouquet doesn't look too bad, and the white shirt looks pretty good as well. The camera's Night Portrait mode combines the flash with a longer shutter time, but takes away the exposure compensation adjustment. It produced more even lighting and a more pleasant look, but a modest underexposure in the process.

Auto White Balance

Incandescent White Balance

Slight color casts, but overall results much better than average.

This shot is always a very tough test of a camera's white balance capability, given the strong, yellowish color cast of the household incandescent bulbs used for the lighting. The DX7590 Zoom's Incandescent white balance setting did the best job here, leaving just enough warm cast to evoke the mood of the original shot. The Auto setting also produced reasonably good results, though the warm cast was stronger. The main shot was taken with a +0.7 EV exposure compensation adjustment, which gives a good exposure without any harsh highlights. Skin tones are a little pink from the red cast, and the blue flowers in the bouquet are dark and purplish (almost to be expected with this shot though). Additionally, the bright red flowers have strong pink tints. Still, minor quibbles aside, the DX7590 does much better than average on this shot.

To view the entire exposure series from zero to +1.0 EV, see files 759INTP0.HTM through 759INTP3.HTM on the thumbnail index page.

ISO Series:
Noise is generally moderate on the DX7590 Zoom, and levels are pretty low with the ISO 80 and 100 settings. At ISO 200, the noise level increases relatively little, but the camera achieves that modest increase at the expense of considerable subject detail. At ISO 400, the image looks almost like a watercolor painting, with large areas of Marti's hair flattened out to an undifferentiated smudge.

Auto White Balance

Daylight White Balance

High resolution and detail, although a slight color cast.

Though just slightly reddish, the DX7590 Zoom's Auto white balance setting produced the best overall color here, with the most accurate white value on the house trim. The Daylight setting resulted in a stronger warm cast. Resolution is very high, with a lot of fine detail visible in the tree limbs and front shrubbery. (The DX7590's five-megapixel CCD stretches the limits of this poster as a test target, even though the poster was made from a 500MB scan of a 4x5 negative shot with a tack-sharp lens.) Details are fairly sharp throughout most of the frame, but soften a bit in the two left corners.

High resolution and detail, though a slightly limited dynamic range.

This image is shot at infinity to test far-field lens performance. NOTE that this image cannot be directly compared to the other "house" shot, which is a poster, shot in the studio. The rendering of detail in the poster will be very different than in this shot, and color values (and even the presence or absence of leaves on the trees!) will vary in this subject as the seasons progress. In general though, you can evaluate detail in the bricks, shingles and window detail, and in the tree branches against the sky. Compression artifacts are most likely to show in the trim along the edge of the roof, in the bricks, or in the relatively "flat" areas in the windows.

This is my ultimate "resolution shot," given the infinite range of detail in a natural scene like this, and the DX7590 Zoom performs well. The camera captures a lot of fine detail in the tree limbs over the roof, as well as in the fine foliage in front of the house. However, details are slightly soft throughout the frame, with increased softness in the corners of the frame. The camera loses a lot of detail in the bright white paint surrounding the bay window, which is a difficult area for many digicams to contend with. Detail is better in the shadow area above the front door, but it's clear that the camera's high default contrast limits its dynamic range somewhat. Overall color looks good however, though the exposure is bright. The table below shows a standard resolution and quality series, followed by ISO, sharpness, saturation, and color series.

Resolution Series:

ISO Series:
The results here are much the same as in the Indoor Portrait test above: The DX7590 generally keeps noise levels low, but at a very high cost in terms of subject detail. Even at ISO 80, it's clear that at least some of the softness of its images is caused by its noise suppression algorithms.

Sharpness Series:
A good range of sharpness adjustment: The "High" setting should look good on smaller inkjet prints, the "Low" setting takes unsharp masking well in Photoshop for best detail, and "Normal" is a good compromise between the two.

Saturation Series:
A useful range of color saturation adjustment.

Saturation Series
Low	Normal	High

Color Series:

Color Series
Normal	Black & White	Sepia

Lens Zoom Range

Excellent 10x zoom range.

I routinely shoot this series of images to show the field of view for each camera, with the lens at full wide angle, at maximum telephoto (10x, in this case), and at full telephoto with the digital zoom enabled. The DX7590 Zoom's lens is equivalent to a 38-380mm zoom on a 35mm camera. That corresponds to a moderate wide angle to a very substantial telephoto. Following are the results at each zoom setting.

	Wide Angle
	10x Telephoto
	3x Digital Telephoto

Auto White Balance

Daylight White Balance

Slightly magenta cast with the Auto white balance setting, but good results overall. Great detail and resolution.

This shot is often a tough test for digicams, as the abundance of blue in the composition frequently tricks white balance systems into producing a warm color balance. The DX7590 Zoom's Auto white balance setting did the best job here, despite a very slight magenta cast. (The Daylight setting actually resulted in a stronger red cast.) Skin tones are slightly pink, but still reasonable. However, the blue robe and background have a few purplish tints that aren't in the original image. Resolution is excellent, as the embroidery on the blue robe and red vest shows a lot of fine detail. (The original data file for this poster was only 20MB though, so cameras like the DX7590 are definitely capable of showing more detail than the poster has in it.)

Standard Macro Shot

Macro with Flash

A small macro area with great detail, though the flash really isn't usable this close.

The DX7590 Zoom performed pretty well in the macro category, capturing a minimum area of only 2.18 x 1.63 inches (55 x 41 millimeters). Resolution is very high, and a lot of fine detail is visible in the brooch, coins, and dollar bill. Details are fairly sharp overall, but soften in the four corners of the frame. (The brooch and coins are already slightly soft from the shallow depth of field at such a close shooting range.) Color and exposure both look good. The DX7590's flash had a very hard time here, as it was almost entirely blocked by the long lens, and underexposed the shot with a very strong shadow in the lower portion of the frame. (Definitely plan on using external lighting for macro shots.)

Auto White Balance

Daylight White Balance

Good overall exposure, and nice color, despite a slight red cast.

I chose the DX7590 Zoom's Auto white balance setting for the main image here, though it had a very slight red tint. The Daylight setting resulted in a much stronger red cast. Still, overall color here is very good, with good saturation in the large color blocks, and generally accurate hue. Exposure is about right, and the DX7590 distinguishes the subtle tonal variations of the Q60 target well. The shadow area of the charcoal briquettes shows moderate detail, with a moderate level of noise.


Now, for the REAL technoids, Imatest!

I've recently begun using Norman Koren's excellent "Imatest" analysis program for quantitative, thoroughly objective analysis of digicam test images. For those interested, I've prepared a page summarizing what Imatest showed me about the DX7590's images.


The results in the tests below mirror those seen above in other test shots. The test series are repeated here without further comment, for the benefit of our more quantitatively-oriented readers.

ISO Series:

Saturation Series:

Saturation Series
Low	Normal	High

Color Series:

Color Series
Normal	Black & White	Sepia

Low-Light Tests

Good low-light shooting performance, with fairly low noise and good color. Autofocus works down to very low light levels.

The DX7590 Zoom produced clear, bright, usable images down to the 1/16 foot-candle (0.67 lux) limit of my test, with good color at the 200, 400, and 800 ISO settings. At ISOs 80 and 100, however, images were bright only as low as 1/8 foot-candle (1.3 lux). Noise was actually pretty low at ISOs 80 to 200, though it became more apparent at the 400 and 800 settings, as you might expect. At ISO 800, the camera restricts the image size to the 1.7 megapixel size, reducing image noise levels by averaging together the data from adjacent sensor pixels. Overall, I was surprised by how little the image noise seemed to increase at low light levels relative to levels I saw under daylight conditions. Apparently, having taken the hit for reduced subject detail up front, few additional tradeoffs had to be made at low light levels. Another positive note: The DX7590's autofocus system works very well at low light levels, producing sharp images at the lowest light level we test at, for all ISOs above 80. The table below shows the best exposure I was able to obtain for each of a range of illumination levels. Images in this table (like all sample photos) are untouched, exactly as they came from the camera.

(Note: If you'd like to use a light meter to check light levels for subjects you might be interested in shooting, a light level of one foot-candle corresponds to a normal exposure of two seconds at f/2.8 and ISO 100.)

	1 fc 11 lux	1/2 fc 5.5 lux	1/4 fc 2.7 lux	1/8 fc 1.3 lux	1/16 fc 0.67 lux
ISO 80	3.2 sec f2.8	6 sec f2.8	10 sec f2.8	16 sec f2.8	16 sec f2.8
ISO 100	2.5 sec f2.8	5 sec f2.8	8 sec f2.8	16 sec f2.8	16 sec f2.8
ISO 200	1.3 sec f2.8	2.5 sec f2.8	4 sec f2.8	8 sec f2.8	16 sec f2.8
ISO 400	1/1 sec f2.8	1.3 sec f2.8	2 sec f2.8	4 sec f2.8	10 sec f2.8
ISO 800	1/3 sec f2.8	1/1 sec f2.8	1 sec f2.8	2 sec f2.8	5 sec f2.8

Flash Range Test

A powerful flash, with excellent brightness all the way to the 14 foot limit of our test.

In my testing, the DX7590 Zoom's flash illuminated the test target all the way out to 14 feet, without any significant decrease in intensity. Below is the flash range series, with distances from eight to 14 feet from the target.

8 ft	9 ft	10 ft	11 ft	12 ft	13 ft	14 ft
1/100 sec f3.2 ISO 80	1/100 sec f3.2 ISO 80	1/100 sec f3.2 ISO 80	1/125 sec f3.2 ISO 80	1/125 sec f3.2 ISO 80	1/125 sec f3.2 ISO 80	1/160 sec f3.2 ISO 80

ISO-12233 (WG-18) Resolution Test

High resolution, 1,150 lines of "strong detail." Lower than average barrel and pincushion distortion.

The DX7590 Zoom performed well on the "laboratory" resolution test chart. It started showing artifacts in the test patterns at resolutions as low as 800 lines per picture height, in both horizontal and vertical directions. I found "strong detail" out to at least 1,150 lines, although some reviewers might argue for 1,200 lines or higher. (I tend to be more conservative than some in my evaluation of res-target results, being unwilling to credit cameras for resolution levels at which artifacts begin to dominate over subject detail.) "Extinction" of the target patterns didn't occur until about 1,500 lines.

Optical distortion on the DX7590 Zoom is lower than average at the wide-angle end, where I measured approximately 0.6 percent barrel distortion. The telephoto end fared even better, as I couldn't find even one full pixel of barrel or pincushion distortion. (On average, consumer digicams tend to show about 0.8 percent barrel distortion at wide angle, and from 0.0-0.3 percent pincushion at telephoto. The DX7590's lens thus does better than average, unusual for a long-zoom design.) Chromatic aberration is moderate at wide angle and medium focal lengths, but high at the telephoto end, showing eight or more pixels of moderate coloration on either side of the target lines. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.)

Resolution Series, 50mm

Wide Angle	"Fine" JPEG	"Normal" JPEG
2,576 x 1,932	759RES2576F	759RES2576N
2,304 x 1,728	759RES2048	-
2,048 x 1,536	759RES2304	-
1,552 x 1,164	759RES1552	-

Resolution Test, Zoom Series

2,576 x 1,932 (Fine, Wide)	759RESW
2,576 x 1,932 (Fine, Tele)	759REST

Sharpness Series