Minolta DiMAGE 7iMinolta updates their revolutionary 5 megapixel electronic SLR with numerous enhancements, keeps the excellent lens.
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Page 4:ViewfinderReview First Posted: 6/15/2002
As was the case with the original Dimage 7, the viewfinder is one of the most interesting aspects of the Dimage 7i. It employs a "Digital Hyper Viewfinder" as well as an LCD monitor for composing shots. The Digital Hyper Viewfinder display would generically be called an "Electronic Viewfinder" (EVF), and is essentially a miniaturized version of the LCD monitor, complete with image information display.
I've long held a hearty dislike of EVFs, for a variety of reasons. For one,
resolution is often considerably less than the rear-panel LCD, and the view
doesn't remotely compare to that through a purely optical viewfinder. A bigger
concern though, is that most EVF displays are woefully inadequate for low-light
shooting. The high refresh rate required to provide a "live" view
of the subject means that the CCD just can't collect enough light in each frame
to make the EVF display usable. Time and again, I've seen EVF-equipped digicams
that are capable of taking pictures in conditions far darker than levels at
which you can see what you're shooting in the EVF. Without a low-light-capable
viewfinder, you're reduced to guessing where your subject is in the viewfinder.
That said, Minolta's EVFs in the Dimage 7 and now the 7i have proven to be exceptions to my thinking. The Dimage 7i's EVF works down to incredibly low light levels, and also has surprisingly high resolution under normal lighting. The EVF uses a reflective ferroelectric LCD display, with 122,000 pixels in it, a slight increase from the 118,000 pixels of the original Dimage 7. The 122K pixel rating is deceptively conservative though, since each pixel shows full continuous-tone color, rather than the separate red, green, or blue pixels of conventional LCDs. The resulting display thus looks much smoother and more detailed than conventional EVFs, with none of the red/green/blue pointillist appearance common to the genre.
Beyond higher apparent resolution though, the Dimage 7i's EVF is remarkably usable at low light levels. Below a certain light level, it switches from a color display to a monochrome one (although the final camera images are still captured in color), apparently as a way of increasing sensitivity and reducing image noise. Whatever the case, the net result is that the EVF on the Dimage 7i is at least as sensitive as my own eyes at a given illumination level, making it eminently usable at any light level most users will care to shoot at. Given that it's about as sensitive as the average eyeball, it's fair to say that a purely optical viewfinder wouldn't improve low-light capability a great deal.
The Dimage 7i's EVF also features the innovative auto-switching capability first seen in the original Dimage 7. You can choose to have the viewfinder display always appear on either the LCD or EVF, or switch between the two automatically. Inset behind a pair of vertical windows on the right side of the viewfinder, a set of infrared sensors detect your eye as it approaches the viewfinder, switching the view to the EVF and disabling the LCD monitor if you have the auto-switching option enabled. To save on battery power, you can optionally (through the Custom Settings menu) set the Auto mode to simply turn the EVF on and off, keeping the LCD monitor disabled. The auto-on option for the EVF isn't instantaneous, but it's pretty fast - I clocked it at roughly 0.3 seconds (assuming my finger was fast enough on the stopwatch). The only complaint I have about the auto-on feature of the EVF is that it can leave the EVF powered up when the camera is hanging from the neckstrap. -- In that position, the EVF eyepiece will be pressed against your chest, triggering the infrared eyeball-detector circuit. A minor point, and one for which there may not be any design-based cure, but I thought it worth mentioning, in case it'd prevent a reader from draining their batteries unexpectedly. (Flipping the tilting eyepiece assembly up when carrying it would avoid this problem, if you can just remember to do so reliably.)
As mentioned earlier, the electronic viewfinder eyepiece tilts upward 90 degrees, offering a range of viewing angles. A Diopter Control dial adjusts the viewfinder to accommodate eyeglass wearers, across a range of 5 to +0.5 diopters. (This covers a wider range of eyesight than I'm accustomed to seeing in eyepiece adjustments. It handled my 20/200 vision with no trouble at all.) The viewfinder has a reasonably high eyepoint, making it quite usable with eyeglasses, but the field of view is slightly restricted when your eye is further from the eyepiece.
Nothing in this world is perfect, of course, and the Dimage 7i's EVF is no exception. The EVF on the original Dimage 7 had several deficiencies, some of which are still present with the 7i. While I didn't have a Dimage 7 in hand to make direct A/B comparisons with, there does seem to have been noticeable overall improvement in several areas though. Here are the main issues:
- Eyepiece optics. - Several users previously complained to me of blurriness in the Dimage 7's viewfinder, prompting me to take a closer look. When I did, I found that I sometimes got a slightly blurry view in the eyepiece, the result looking a bit like it arose from a curvature of field problem in the eyepiece optics. (Curvature of field is a common lens aberration, in which the center and edges of the field of view come into focus at different focal distances.) In the Dimage 7i, the problem looks less like curvature of field to me than it does a circle of coverage limitation. - I could see the corners of the EVF screen quite clearly if I just moved my eye slightly to one side or the other. With my eyeball centered over the eyepiece though, the corners of the viewfinder appeared slightly obscured. I don't see this as a fatal flaw, but can imagine that some users would find it annoying.
- The "crackled glass" effect. This was far and away the biggest complaint I heard from Dimage 7 users. This is evidently a consequence of the ferroelectric LCD's square, tightly abutting pixels. If you have a subject in view with lots of very fine, sharply-contrasting detail, the viewfinder image gets a "crackled" look to it. It seems that these artifacts result from the fact that, while the square, closely tiled LCD pixels give a very smooth appearance with most subjects, the pixel data can change very abruptly from one to the next. On a conventional LCD, with the R, G, and B pixels spread across a bit of an area, your eye tends to smooth over inter-pixel transitions. With the ferroelectric LCD though, adjacent pixels can change brightness very abruptly, causing this "crackled" appearance. The D7i's EVF seemed slightly less prone to this problem than that on the original D7. Again, it's hard to tell, because I didn't have a D7 on hand to compare it to directly. - And I wouldn't expect much difference given the relatively slight increase in pixel count between the two models.
One thing I did notice with the D7i though, was that its EVF seemed to have a much higher refresh rate. On the D7, if you moved the camera quickly (or your subject moved quickly across the field of view), there'd be a very visible "tearing" of the display. This could be a little troublesome for situations like sports shooting, where you might want to pan the camera fairly quickly to follow a fast-moving subject. Again, I couldn't compare directly with a D7, but the EVF display on the 7i certainly seemed much more stable in this respect.
- Blown highlights. - In extended use, the biggest complaint I personally had about the D7's EVF was that it was very hard to judge what was going on in highlight areas. In landscape shots where I cared about cloud detail for instance, it was very hard to compose for the sky portion of the image, because the bright areas tended to wash out to a featureless expanse of white. This is somewhat due to the tendency of the camera itself to drop highlight detail, but I lay most of the blame for the viewfinder highlights on the EVF system. With the D7i, it seemed that the display was a little less prone to this, but again it was a hard to say precisely, without having a D7 to compare it to directly. If the bulk of the frame was filled with a darker subject (the landscape example mentioned above, for instance), it was still nearly impossible to see what was going on in the sky. If the scene was more nearly the same brightness though, I didn't have any trouble picking out cloud details.
If the subject was one that allowed a little more time to fiddle with the camera before shooting, I found I could make good use of the spot-metering button to temporarily lock an exposure setting for the sky, reframe my picture to position the cloud details where I wanted them, then release the spot button and let the camera calculate exposure normally for the main subject. Not ideal but workable, IMHO, poor highlight detail is the biggest limitation of Minolta's otherwise excellent EVF design.
Despite the limitations mentioned above, I still like the Dimage 7i's EVF better than others I've tried. That said, I do still prefer optical viewfinders if they're available. With more long-ratio zoom lenses on digicams though, expect to see more and more EVFs along with them. It's just too difficult to create a 10x zoom ratio optical viewfinder that's lightweight, accurate, and affordable.
The rear-panel, 1.8-inch, TFT color LCD monitor is also comprised of about 122,000 pixels, and offers a very bright, clear image display. Like the electronic viewfinder, the LCD monitor displays a range of exposure and camera information in both Record and Playback modes, activated by the i+ button on the Display Mode dial. Through the Setup menu, you can set the number and type of displays available through the i+ button. Most notable are the Histogram, Grid, and Scale modes. The Histogram setting displays a small "live" histogram overlaid on the viewfinder image, showing the distribution of tonal information in the image. This is handy tool for determining any potential over or underexposure, before capturing an image. The Grid option displays a 20-segment grid over the image area, helping you line up shots. Scale mode displays a crosshair type scale, which divides the image into quadrants. The histogram display is a nice feature (although I'd like to see it coupled with the option to "blink" blown-out highlights), and the grid and scale modes are very handy framing aids.
In terms of accuracy, both the EVF and rear panel LCD provide very accurate framing, showing almost exactly 100% of the final image area.
Playback mode, the Dimage 7i displays a fair amount of image information, which
is again controlled by the i+ button on the Display Mode dial. A histogram feature
is also available here, for checking on the tonal range of the captured image.
(I'd really like to see an option that blinked blown highlights though, because
a histogram display alone doesn't help much if you've got just a few blown highlights
in a photo.)
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