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Minolta DiMAGE A1

Minolta updates their revolutionary five-megapixel electronic SLR with faster shutter speeds, an Anti-Shake mode, 14-bit A/D, and a tilting LCD monitor, among other improvements.

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Page 12:Test Results & Conclusion

Review First Posted: 08/08/2003, Updated: 11/10/03

Test Results
In keeping with my standard test policy, the comments given here summarize only my key findings. For a full commentary on each of the test images, see the DiMAGE A1's "pictures" page.

As with all Imaging Resource product tests, I encourage you to let your own eyes be the judge of how well the camera performed. Explore the images on the pictures page, to see how the A1's images compare to other cameras you may be considering.

  • Color: Excellent color, hue-accurate and appropriately saturated. The A1 did a really excellent job with color overall, producing pleasing, accurate color in most of my test scenarios. Colors were hue-accurate and neither over- nor under-saturated. The Auto white balance setting did quite well outdoors, while the Manual option fared better under more challenging light sources. (Although the Incandescent setting did quite a good job with the difficult household incandescent lighting of my Indoor Portrait test.) Skin tones were just about right, and the tricky blue flowers of the Outdoor Portrait came out quite nicely as well. (Slightly darker than in real life, but with just the right shade of blue.) Overall, arguably the best color I've seen yet from Minolta, and excellent by any standard.

  • Exposure: Good exposure accuracy. A contrasty tone curve, but an effective contrast adjustment. The A1's exposure system did a pretty good job, responding to the various metering challenges in my test suite more or less the same as other top-ranked cameras. (That is, it required about the same amount of exposure compensation as most other cameras, slightly less than average compensation in the Outdoor Portrait test.) The A1's default tone curve is fairly contrasty, but its optional contrast adjustment helps tame the contrast when working with harsh lighting.

  • Resolution/Sharpness: High resolution, 1,150 lines of "strong detail." The A1 performed pretty well on our "laboratory" resolution test chart. It started showing artifacts in the test patterns at resolutions as low as 800 lines per picture height vertically, and as low as 600 lines horizontally, but I found "strong detail" out to at last 1,150 lines both vertically and horizontally. "Extinction" of the target patterns occurred around 1,350 lines. One odd note though: For some reason, there were a large number of tiny black specks between the target lines. (These were most visible between the finely-spaced diagonal and horizontal lines, although they were also quite evident between the lines of the hyperbolic resolution wedges.) Given the regular spacing of these artifacts, I have to assume that they somehow result from the A1's image-processing algorithms. I didn't notice these artifacts in any of my "natural" test subjects, perhaps because they only appear to be triggered by very finely spaced, high-contrast detail in the subject.

  • Image Noise: Noise levels and "grain pattern" roughly in the middle of the 5-megapixel pack. While I don't currently perform a quantitative noise test, I've decided to begin including subjective comments on noise performance here, due to the high level of interest among readers in the topic. As CCD resolution has increased (and pixel dimensions on average have shrunk), image noise has become an increasing factor. Five-megapixel digicams on average show higher image noise than did their two- and three-megapixel forebears. In the case of the A1, its noise levels are clearly higher than those of many lower-resolution cameras, but is about in the middle of the range of five-megapixel models I've looked at. It's "grain pattern" is also about in the middle of the range, coarser than some and less coarse than others. (I've found that the "grain size" of image noise seems to affect how objectionable it is as much or more so than the absolute amount of it. More tightly-patterned noise is much less apparent than that with a coarser pattern. The A1 falls somewhere in the middle of the pack, both in terms of absolute quantity and pattern size.

  • Closeups: Excellent macro performance, and the flash does a good job up close. The A1 performed well in the macro category, capturing a tiny minimum area of only 1.96 x 1.47 inches (50 x 37 millimeters). Resolution was very high, with strong detail in the dollar bill. The coins and brooch were soft due to the very short shooting distance, an optical fact of life at such short shooting distances, and not the fault of the camera. There was some softness in the corners of this shot, mainly in the top left corner of the frame, but not bad when compared to the results produced by most cameras I test. (The soft coins and brooch make it difficult to determine corner softness in the remaining corners.) The A1's flash did a very good job throttling down for the macro area, and exposed the shot evenly. An excellent performance overall, particularly with the flash.

  • Night Shots: Excellent low-light performance with good color and low noise, and a surprisingly sensitive autofocus system. The DiMAGE A1 offers full manual exposure control, and a maximum exposure time of 30 seconds. It thus does very well under dim lighting, especially given its adjustable ISO and Noise Reduction features. The A1 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. The camera's Noise Reduction feature did a good job of controlling image noise, although noise was still pretty high at the 800 ISO setting. Still, a very good job overall. The A1 doesn't have an autofocus-assist illuminator, but I found its AF system to be surprisingly sensitive, focusing at light levels as low as 1/4 foot-candle (about a quarter of the brightness of a typical city night scene). I did find though, that the AF system sometimes became confused when it was near its low-light limit, indicating focus when it wasn't even close. Fortunately though, in those situations, I could almost always tell that it was out of focus, simply by looking at image in the LCD display, and refocusing by half-pressing the shutter button again generally did the trick.

  • Viewfinder Accuracy: Excellent accuracy from the electronic viewfinder. The A1's electronic "optical" viewfinder (EVF) was very accurate, showing almost exactly 100 percent of the final frame at both wide angle and telephoto zoom settings. The LCD monitor was likewise very accurate, since it shows the same view, just on a larger screen. Given that I like LCD monitors to be as close to 100 percent accuracy as possible, the A1's LCD monitor is essentially perfect in this regard. (The A1's EVF is also nice, in that it works down to unusually low light levels, avoiding a common failing of electronic viewfinders.)

  • Optical Distortion: Higher than average barrel distortion at wide angle, but very low chromatic aberration and very sharp images, from corner to corner. Optical distortion on the A1 was somewhat high at the wide-angle end, where I measured approximately 1.0 percent barrel distortion. The telephoto end fared much better, as I found only 0.3 percent pincushion distortion there. While its distortion at wide-angle is higher than average, the overall results are still quite good for a long-ratio zoom lens, as such lenses generally tend to show much higher distortion levels than lower-ratio zooms. Chromatic aberration was very low, showing only 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.) The A1's images were also unusually sharp from corner to corner, with very little of the softness in the corners that I've come to expect from digicam lenses. All in all, the A1's lens appears to be of unusually high quality.

  • Shutter lag and cycle time: Very fast shutter response, great cycle time. I refrained from reporting on shutter lag and cycle times when I first looked at a prototype A1, and it was well that I did: Compared to the somewhat sluggish response of that early model, the production-level A1 proved to be one of the faster-responding digicams on the market. Full-autofocus shutter lag hovers right around 0.6 seconds, regardless of the zoom setting, near the fastest of any prosumer digicam I've tested. Cycle time runs a little over a second for large/fine files, and the buffer memory holds as many as 5-6 shots before the camera has to slow down to wait for the memory card. While by no means in the same category as most digital SLRs, this would be a great prosumer camera for shooting sports and other fast-paced action.

  • Battery Life: Really excellent battery life. Thanks to a beefy Li-Ion battery pack, the DiMAGE A1 has about the best battery life of any prosumer camera I've tested. I'd still advise purchasing a second battery on general principles, but this camera is one that you could get by better than most with just a single battery pack.


Conclusion

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Throughout their evolution, I have continued to be impressed with Minolta's DiMAGE series of digicams, from the 7 to the 7i, 7Hi, and now the A1. The new DiMAGE A1 is a very nice upgrade to the 7Hi, adding the benefits of faster shutter speeds, an effective Anti-Shake option, tracking autofocus, an intelligent grip sensor, 14-bit A/D conversion, a tilting LCD monitor, and remote capture capability to an already great camera. The tack-sharp, long-ratio zoom lens and fast shutter response make it a nearly ideal camera for amateur sports shooting, while the availability of a full auto mode is good for novices who want to gradually learn more. As an added bonus, the DiMAGE A1 integrates beautifully with Minolta's dedicated flash units, with built-in wireless TTL flash metering capability and full control over the flashes' zoom heads. (Minolta's very flexible twin-headed macro flash system deserves special mention here as well, as one of the more flexible macro lighting systems I've seen.) Support of Adobe RGB, including the ability to embed a color-space tag in its file headers make it well suited for use in professional, color-managed work environments. Image quality is excellent as well, with high resolution, very good color, appropriate saturation, and contrast and saturation controls that cover a useful range in fine steps. (The odd "speck" artifacts I saw in the resolution target images didn't appear in any natural subjects I shot, so I'm not giving the camera bad marks for them here.) With its panoply of features and flexible control, the DiMAGE A1 is a serious contender at the high end of the "prosumer" digicam market. Highly recommended.

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