Digital Cameras - Minolta Dimage Xt 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, ISO setting, compression setting, etc. Rather than clutter the page below with *all* that detail, we're posting the Thumber index so only those interested in the information need wade through it!|
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 Dimage Xt did a pretty good job.
The shot at right was taken with a +0.7 EV exposure compensation adjustment, which brightened the midtones nicely, at the expense of only the brightest highlight details. I chose the Daylight white balance as the most accurate overall, despite a very slight warm cast. The Auto setting produced pale and slightly greenish images.
Marti's skin tones are just a little warm, but still look pretty good. However, the blue flowers in the bouquet are a little darker than they are in real life. (A common problem for many digicams with this shot. For reference, the flowers are a light navy blue, with only slight purplish tints in them.) I also noticed reddish/magenta tints on the white shirt. The Xt did a good job with strong reds and greens however, rendering them very accurately with none of the oversaturation I'm accustomed to seeing from so many cameras. Resolution is high, with a lot of crisp, fine detail visible throughout the frame, even in the shadows. Image noise the shadows is quite low. Overall, a very nice job.
To view the entire exposure series from zero to +1.0 EV, see files XTOUTDP0.HTM
through XTOUTDP3.HTM on the thumbnail index page.
Great resolution and detail, and good exposure.
Results are similar to the wider shot above in terms of color and exposure, and the Xt's 3x zoom lens helps prevent distortion of Marti's features. Detail is much stronger in this shot, with sharp, well-defined details in Marti's face and hair. The shot at right was taken with a +0.3 EV exposure compensation adjustment, which produced a nicely balanced exposure with only the strongest highlights in the shirt collar blown out. Shadow detail is again strong, with low noise.
To view the entire exposure series from zero to +1.0 EV, see files XTFACDP0.HTM
through XTFACDP3.HTM on the thumbnail index page.
Moderate underexposure at the default setting, but good performance, particularly with the Slow-Sync mode.
The Xt's built-in flash does a pretty good job here, though it is quite dim at the default exposure setting. The shot at right has a +1.3 EV exposure compensation adjustment, which is slightly higher than the average required on this shot. (Most cameras seem to require about a +1.0 EV exposure compensation here.) Overall color is pretty good, though the background incandescent lighting creates a mild orange cast on the back wall and on some of Marti's features. The camera's Slow-Sync flash mode combines the flash with a slower exposure, which results in a brighter overall image. Taken with a +1.0 EV exposure compensation adjustment, the shot at right has more even lighting, and a brighter exposure. The orange cast is lighter, but the flash creates a blue cast on Marti's face and in the shadows. Still though, the balance between the flash and room lighting is better than average here.
To view the entire exposure series from zero to +1.3 EV in the Slow-Sync
flash mode, see files XTINFSP0.HTM through XTINFSP4.HTM on the thumbnail
Slight color casts with both white balances tested, but overall very good results with the Auto setting.
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 Xt's Auto white balance
produced the best color here, despite a slight pinkish cast. (The Incandescent
setting resulted in a warm, brownish cast.) Marti's skin tone is very
pink, as are the red flowers in the bouquet. Additionally, the blue flowers
are very dark and purplish, a common problem with this shot. The main
shot has a +1.0 EV exposure compensation adjustment, about average for
this shot among the cameras I've tested, but the result with the Xt is
a tad dark. (I felt that +1.3 EV resulted in
too light an image though. For reference, here's a shot at the default
Good detail and resolution, pretty accurate color. Some positive exposure compensation required for the best exposure.
The Xt's Auto white balance setting produced
the most accurate results here, though the white house trim has a slight
reddish cast. The Daylight white balance resulted
in a slight yellow cast. Surprisingly, the Xt underexposed this shot at
the default exposure setting, so I boosted the
exposure with a +0.3 EV adjustment for the
shots seen at right. (This is pretty unusual on this shot, it's a good
balance of light and dark, so most cameras expose it correctly with their
default exposure setting.) Resolution is high, with good detail in the
tree limbs and shrubbery. Details are pretty sharp throughout the frame,
with only a hint softness in the corners of the image. A good performance,
apart from the need for positive exposure compensation.
Surprisingly good resolution and detail, with good color and dynamic range. Softness in the corners though.
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 Xt does a surprisingly good job for a subcompact camera. Detail in the tree limbs over the roof and the fine foliage in front of the house is very good, and the camera's built-in image sharpening gets things just about right, not overdoing it to the point of producing halos around contrasting objects. The Xt's lens system does produce some distortion in the corners of the frame, visible here as a blurring in the corners, and some signs of chromatic aberration in the upper left-hand corner. The camera does an excellent job of holding onto highlight detail in the white paint on the front of the house though, and shadow detail is very good as well. Overall, a very nice job for a subcompact camera.
Lens Zoom Range
A normal 3x 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 (3x, in this case), and at full telephoto with the digital zoom enabled. The Xt's lens is equivalent to a 37-111mm zoom on a 35mm camera. That corresponds to a moderate wide angle to a moderate telephoto. Following are the results at each zoom setting.
Slight color casts with both white balances, and a slight underexposure, but good resolution and detail.
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 Xt's Auto white
balance setting had a little trouble here, and produced a warm, reddish
color cast. The Daylight setting resulted
in a cooler image, with a magenta cast. Despite the magenta tint, I felt
the Daylight image looked the most natural. The blue background has purplish
tints from the magenta cast that aren't in the original image, as do the
deep shadow areas of the blue robe. As with the House poster shot above,
the Xt underexposed this image slightly, requiring a +0.3 EV exposure
boost to produce the results seen at right. (I'm perplexed by this behavior
in the studio, as the Xt's exposure system otherwise behaved in much the
same way as did those of other cameras I've tested. - Perhaps the infrared
from the studio lights threw the metering off on these tests?) Resolution
is very high, with a lot of fine detail visible in the embroidery of the
A tiny minimum macro area, with good detail.
The Xt captures a surprisingly tiny macro area, at 2.1 x 1.6 inches (40
x 53 millimeters). Resolution is very high, with strong detail in the
coins and brooch. The dollar bill is a bit soft, likely due to the very
shallow depth of field in macro shots like this one: The camera obviously
focused on the surface of the brooch, where you can see very crisp detail.
As is often the case in digicam macro shots, the corners are softer here,
with the softness extending down the entire left and right sides of the
frame. Color looks pretty good, but the Xt's flash
has trouble throttling down for the macro area, blowing out the image
on the right side of the frame. Plan on using external illumination for
the closest shots, but overall, the Xt is an excellent macro performer.
Slight underexposure at the default setting, but good color with the Auto white balance.
The Xt's Auto white balance setting produced
the best color here, though with a slight pink cast. The Daylight
setting produced a warmer color balance. Exposure was dim at the default
setting, so I dialed in a positive adjustment of +0.3 EV. The Xt has no
trouble distinguishing the subtle tonal variations of the Q60 target.
Colors are about right in the large color blocks, with good saturation.
However, I found the red and blue color blocks just a little "hot."
Detail is pretty good in the shadow area of the charcoal briquettes, with
low noise, and the last steps of both gray scales are barely distinguishable.
Overall, a good performance.
Surprisingly good low-light performance, considering the camera's automatic exposure control. Sensitive enough for average city street lighting at night and quite a bit darker. However, autofocus has trouble at light levels lower than 1/2 foot-candle.
Despite the Xt's fully automatic exposure control, the camera actually performs pretty well in low lighting. During my testing, the Xt produced clear, bright, usable images down to the 1/16 foot-candle (0.67 lux) limit of my test at the 400 ISO setting. As I decreased the ISO sensitivity setting, so did the maximum brightness at the lowest light levels, with the ISO 50 setting only getting down to one foot-candle (11 lux), the equivalent of city street lighting at night. The camera's autofocus had some trouble at the lower light levels though, producing soft focus at light levels below 1/2 foot-candle. Color was pretty good with the auto white balance setting. Noise was low at the ISO 50 setting, but increased to a high level at ISO 400. The Xt does have a Noise Reduction option, but I didn't see much difference between the shots with and without it. (Here are sample images without Noise Reduction at the 50, 100, 200, and 400 ISO settings, also linked from the rightmost column of the table below.) 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.
Flash Range Test
A reasonably bright flash, with consistent intensity all the way to 14 feet.
In my testing, the Xt's flash illuminated the test target all the way out to 14 feet, with approximately the same (slightly low) level of intensity. To achieve this, the Xt fudges a little by boosting the ISO to 160. This has become a fairly common approach for manufacturers to use in compact digicams, boosting ISO and accepting the tradeoff of higher image noise in exchange for greater flash range. Below is the flash range series, showing the results obtained with distances from eight to 14 feet from the target.
High resolution, with 1,100 lines of "strong detail." High barrel distortion, and slightly high pincushion though.
The Xt performed well on the "laboratory" resolution test chart. It started showing artifacts in the test patterns at resolutions as low as 650 lines per picture height vertically, and as low as 600 lines horizontally. I found "strong detail" out to about 1,100 lines. (A little more horizontally, a little less vertically.) "Extinction" of the target patterns didn't occur until about 1,250 lines.
Optical distortion on the Xt is higher than average at the wide-angle end, where I measured approximately 1.0 percent barrel distortion. The telephoto end fared only a little better, as I measured a 0.5 percent pincushion distortion. (Typical cameras I test show about 0.8% barrel distortion at wide angle (still way too much, IMHO), and 0.3 percent or less pincushion at telephoto.) There's some fairly noticeable softening in the corners (particularly on the left side of the image), coupled with some chromatic aberration, more of both than I like to see. As excellent a camera as the Xt is, there were obviously some tradeoffs that had to be made in the lens, with sacrifices made in resolution and distortion in the corners of the frame.
Resolution Series, Wide Angle
Resolution Test, Telephoto
Viewfinder Accuracy/Flash Uniformity
Excellent accuracy from the LCD, but a very tight optical viewfinder.
The Xt's optical viewfinder is very tight, showing approximately 75 percent frame accuracy at wide angle, and about 74 percent at telephoto. The LCD monitor proved much more accurate, though actually just slightly loose, showing slightly more than 100 percent of the final image area. Given that I like LCD monitors to be as close to 100 percent accuracy as possible, the Xt's LCD monitor performed pretty well here, but I'd *really* like to see a more accurate optical viewfinder. Flash distribution is fairly even at wide angle, with only moderate falloff at the corners and edges of the frame. At telephoto, flash distribution is more uniform.
Xt Test Images
Xt "Picky Details"
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