Digital Cameras - Kodak EasyShare DX7440 Test Images
|I've begun including links in our reviews to a Thumber-generated index page for the test shots. The Thumber data includes a host of information on the images, including shutter speed, ISOsetting, compression setting, etc. Rather than clutter the page below with *all*that detail, we're posting the Thumber index so only those interested inthe information need wade through it!|
(This is my new "Outdoor" Portrait test - read more about it here.)
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 color temperature and main/fill balance here closely match that of summer sunshine here in North Georgia.) The object is to hold both highlight and shadow detail without producing a "flat" picture with muddy colors. The EasyShare DX7440 did pretty well, but its contrast level was pretty high.
The shot at right was taken with a +0.3 EV exposure compensation adjustment. This left the midtones a little dark, but I couldn't go any brighter without totally losing highlight detail. Despite a reddish cast, I chose the Auto white balance setting as the most accurate overall. The Daylight setting was a bit warmer and yellow.
Skin tones are a little red from the overall color cast, and the blue flowers in the bouquet are darker than in real life. (Many digicams have trouble with this blue. The DX7440 gets the hue nearly right, but the tone is a fair bit darker than the flowers actually are.) The strong greens look about right, and the red flowers are pretty accurate, though a little oversaturated. Resolution is high, and detail is strong in the flower bouquet, though shadow detail is limited and image noise is moderately high.
To view the entire exposure series from -0.3 to +1.3 EV, see files 7440OUT2BAM1.HTM
through 7440OUT2BAP4.HTM on the thumbnail index
Excellent resolution and detail, though again high contrast.
Overall results are similar to the wider shot above, with high contrast. Midtones are slightly dark, and highlights are strong. The shot at right was taken with a +0.3 EV exposure compensation adjustment. The DX7440's 4x zoom lens does a good job of preventing any geometric distortion of Marti's features. Resolution and detail are much higher in Marti's face and hair, with pretty good definition.
To view the entire exposure series from -0.3 to +1.0 EV, see files 7440FAC2BAM1.HTM
through 7440FAC2BAP3.HTM on the thumbnail index
Indoor Portrait, Flash:
Only slight exposure compensation required to produce very good results. A slightly warm color balance from the strong room lighting.
The DX7440's built-in flash produced a good image at the default
exposure setting, though overall results were just a trifle dim. With
a +0.3 EV exposure compensation adjustment,
the exposure was brighter with good coverage. (At +0.7
EV, the exposure was much too bright.) Overall color is just slightly
reddish from the Auto white balance, with a hint of an orange cast on
the back wall and on Marti's hair from the Incandescent room lighting.
Indoor Portrait, No Flash:
Generally good color, with only slight color casts with both settings, and good exposure as well.
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 DX7440's Auto white balance setting resulted in a slightly reddish color balance, while the Incandescent setting produced a stronger yellow cast. While neither white balance setting was dead-on, both are within the range of what I'd consider acceptable, and I selected the Auto setting for the main example for this shot. The red cast increases the pink in Marti's skin tones, and makes the blue flowers dark and purplish, but the results overall are quite good when compared to most cameras' auto white balance photos on this test. The shot at right was taken with a +0.7 EV exposure compensation adjustment, a little less than what's required by most cameras.
To view the entire exposure series from zero to +1.0 EV, see files 7440INAP0.HTM through 7440INAP3.HTM on the thumbnail index page.
Good resolution and detail, but not up to the levels of the best 4-megapixel models. Slightly reddish color balance.
Though slightly red overall, the DX7440's Auto
white balance setting produced the most accurate overall color, as the
Daylight setting had a warmer cast. Resolution
is high, with good detail in the tree limbs above the roof and in front
shrubbery. The brick pattern also shows good detail, but the image overall
isn't quite as sharp as the best (and admittedly considerably more expensive)
four-megapixel digicams. Plenty of resolution for sharp 8x10 prints, but
true "enthusiast" shooters will probably want to look for a
camera that snaps sharper images. Despite the slight softness overall
though, details are equally sharp throughout the frame, from corner to
corner, something I look for in a digicam.
Limited dynamic range, but good resolution and detail.
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
DX7440 does a great job in that respect. The tree limbs over the roof
and fine foliage in front of the house have good detail, with clear definition
in the leaves (and in my cameo appearance in the side yard!). Details
appear reasonably sharp from corner to corner. Again, while the DX7440's
image sharpness isn't quite up to the levels of the best 4 megapixel digicams,
it's not too far off the mark, certainly adequate for sharp 8x10 prints.
The camera slightly overexposed this image with its default settings,
and the combination of minor overexposure with the camera's high native
contrast resulted in the loss of essentially all detail in the bright
white paint surrounding the bay window, evidence of a limited dynamic
range from the bright exposure. The slight overexposure did help detail
in the shadows above the door though. There's also some evidence of lens
flare in the tree limbs against the sky, but the overexposure there produce
visible flare on all but the most elite camera lenses. Overall color looks
good with the Auto white balance setting. The table below shows a standard
resolution and quality series, followed by ISO, sharpness, saturation,
and color series.
Lens Zoom Range
A good 4x 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 (4x, in this case), and at full telephoto with the digital zoom enabled. The DX7440's lens is equivalent to a 33-132mm zoom on a 35mm camera. That corresponds to a range from a fairly wide angle to a moderate telephoto. Following are the results at each zoom setting.
A slightly reddish color cast, but 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. Both the DX7440's Auto
and Daylight white balance settings produced
reddish color casts, Daylight more so than Auto. Skin tones are a little
red, and the blue background has a purple tint (as do the deep shadows
of the blue robe), but the overall color with the Auto white balance setting
isn't too bad. Resolution is high, and detail is strong in the embroidery
of the blue robe, as well as in the beaded necklaces, flower garland,
and other areas of fine detail.
An average size macro area, with some softness in the corners but overall good detail. A slight reddish color balance with the photoflood lighting, and the flash is tricked by the shiny coins.
The DX7440 turned in about an average performance in the macro category,
capturing a minimum area of 2.99 x 2.24 inches (76 x 57 millimeters).
Resolution was high, with clear, sharp details in the brooch, coins, and
dollar bill. As with the macro modes of most digicams I test, there was
some softness in each of the four corners, but it didn't extend very far
into the frame. Color balance was pinkish with the Auto white balance
setting, but exposure was good. Undoubtedly tricked by the reflections
from the coins and the brooch, the DX7440's flash
throttled down a little too much for the macro area, producing a dim exposure.
(With less reflective subjects though, the DX7440's flash should work
well for macro shooting.)
"Davebox" Test Target
Correct exposure but high contrast. A slightly warm color balance and high saturation. (The "Low Saturation" option is actually very close to accurate.)
The DX7440's Auto white balance setting produced
a warm color balance here, though overall results were better than the
stronger red cast of the Daylight setting.
Exposure is about right, although contrast is high, yet the camera distinguishes
the subtle tonal variations of the Q60 target fairly well. Colors are
generally hue-accurate, but pretty oversaturated. (My results from Imatest
show an average saturation of 120%, quite a bit higher than usual.) Shadow
detail is minimal in the charcoal briquettes, with high image noise. Most
consumers tend to like highly saturated color, so the DX7440's images
may in fact appeal to the average user. To its great credit though, while
the DX7440 really pumps up bright colors, it seems to be much more careful
with pastels, particularly Caucasian skin tones. Another positive note
is that the DX7440's "low saturation" setting actually produces
very accurate color, good for users more interested in accurate reproduction
than snappy-looking photos.
Excellent low-light performance, with good color and exposure in almost total darkness. Very good low-light focusing as well.
With a maximum exposure time of 64 seconds and full manual exposure control, the DX7440 is well-suited for low-light shooting. The camera produced clear, bright, usable images down to the 1/16 foot-candle (0.67 lux) limit of my test, with good color at all four ISO settings. Noise was very low at the 80 and 100 ISO settings, and only increased to a moderate level at ISO 200. Even at ISO 400, image noise is lower than I'd expect, but as we saw earlier, the way the DX7440 achieves its low noise levels at high ISO settings is by trading away a lot of subtle subject detail. 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 our 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.)
Flash Range Test
A low-intensity flash, with significant falloff beyond 8 feet or so.
In my testing, the DX7440's flash illuminated the test target all the way out to 14 feet, although its intensity dropped markedly from 8 feet on out. Flash power remained bright to about nine feet, but fell off significantly as the distance increased. Below is the flash range series, with distances from eight to 14 feet from the target.
High resolution, 1,150 lines of "strong detail." Lower than average barrel distortion.
The DX7440 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, arguably 1,200, lines. "Extinction" of the target patterns didn't occur until about 1,400 lines.
Looking at this target with Imatest, the results were a little confounded by the 7440's high contrast and strong in-camera sharpening, which caused the images to saturate on both ends of the tonal scale. Bottom line, though, the uncorrected average resolution using the "MTF 50" criteria was 1187 LW/PH, dropping to 904 LW/PH when corrected to match the edge profile of a standard 1-pixel radius sharpening.
Optical distortion on the DX7440 is very low at the wide-angle
end, where I measured only 0.2 percent barrel distortion. The telephoto
end fared about the same, also with an 0.2 percent barrel distortion.
Both numbers are quite a bit lower than average. Chromatic aberration
is very low, showing at most about four pixels of very faint coloration
on either side of the target lines. (This distortion is visible as a very
slight colored fringe around the objects at the edges of the field of
view on the resolution target.) Finally, the DX7440's lens seems to hold
sharpness very well out into the corners, with less of the softness there
that I'm accustomed to seeing in digicam images.
Resolution Series, 50mm
Resolution Test, Zoom Series
Viewfinder Accuracy/Flash Uniformity
A tight optical viewfinder, but accurate LCD monitor.
The DX7440's optical viewfinder was somewhat tight at the telephoto
setting, showing about 85 percent of the final frame area. (While a
lot tighter than I like to see, this is actually about average among
consumer digicams.) However, at the wide angle lens position, frame
accuracy was better, showing about 90 percent of the final frame. The
LCD monitor fared much better, showing 99+ percent frame regardless
of lens settings. (Though the measurement lines were just out of frame
at wide angle.) Given that I like LCD monitors to be as close to 100
percent accuracy as possible, the DX7440's LCD monitor performed very
well here, but I'd like to see the optical viewfinder a little more
accurate. Flash distribution is fairly even at wide angle, with just
a little falloff at the corners and edges of the frame. At telephoto,
flash distribution is more uniform, though still with some slight falloff
in the corners.
DX7440 Test Images
DX7440 "Picky Details"
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