Written on: 13/04/2002 by Declan Cowley.
Good optics with and exceptionaly good zoom range.
Autofocus sytem is inadequate for rapidly changing subjects (way too slow).
I have now been using the Minolta Dimage 7 digital camera in the field for two months and have noticed some inherent problems with the camera. There are two significant problems that I have encountered that can significantly affect the ability of the photographer to capture the images he desires.
The first is the built-in flash. Unfortunately Minolta has seen fit not to allow the option of turning OFF the preflash. Experience has now shown that the preflash is of sufficient intensity that most subjects will involuntarily close their eyes. This means that when the main flash actually fires, the subject will have their eyes either partially or fully closed. This also makes the built-in flash UNSUITABLE for people photography.
The only current solution is to use an external flash that does not use preflash. The best option would be for Minolta to allow the preflash to be turned off, this would also make the builtin flash useable as a trigger for external flash units. Hopefully Minolta will allow this option in a (soon I hope) software upgrade.
The second gripe I have is somewhat more serious. This concerns the autofocus system employed by the camera. Even in daylight conditions the autofocus system is way too slow to allow the photographer to capture fast moving subjects (and no, the continuous focus setting does not help). This results in many lost shots, because the camera will not fire as expected, or you get out of focus shots because it did fire. In low light situitations, where one would normally require the flash, the situitation is even worse, resulting in even more lost shots or out of focus shots.
The ONLY solution here to to set the camera to MANUAL FOCUS and leave it there. Under these conditions, the camera actually performs extremely well. Since the camera now does not have to perform autofocus with every shot, the camera's responsiveness to the photographers demands is very high and few, if any, shots will be lost because the camera would not fire. Of course, the burden of making sure the camera is in focus is now placed on the photographer. This does require some diligence as it is quite easy to knock the focus ring while using the camera. In addition, one must watch the focus carefully if you zoom in on a subject. What might be in focus at the wide end of the zoom, might not be in focus at the long end.
Manual focusing is clumsy, at best. The viewfinder is way too low resolution to allow manual focus determination by eye. The zoom feature for focusing is good, but still too grainy for accurate focus determination. So the photographer is left with distance estimation to determine manual focus. One additional gripe I have here, is that the displayed distance is in meters, not feet. While I can mentally do the conversion, I'm afraid my brain still works in feet.
As long as I am on the subject, the viewfinder(s) require some comment. In bright outdoor situitations, the LCD screen on the back of the camera is useless. Just turn it off and save battery power. The EVF is the only option, but it too is very hard to see in bright light. It can really only be used for framing. Trying to determine manual focus is impossible. Oh what I wouldn't give for SLR pentaprism viewfinder. My next digital camera, I guess.
Best option for outdoor shooting is manual focus with aperature priority exposure control. Set the aperture to f8 or smaller and you will have an excellent depth of field, that should take care of most focus situitations. But one must still pay attention to focus when zooming and the shutter speed if you move from one lighting situitation to another.
The optics of the Dimage 7 does provide excellent results at all focal lengths, provided that the subject is in focus. I have found that the fine JPG setting provides the optimum image quality with maximum utilization of storage space. Unless I was going to do some very large enlargements, I really see no need to use either the TIFF or RAW settings, as they really do take up an awful lot of storage space. The JPG setting is saved with minimal compression (ie: very high quality), so image artifacts from the JPG format are minimized.
Before setting off on a digital only trek, I did some informal testing of the different image formats as saved by the camera. Much to my surprise, I found that the fine JPG setting produced LESS artifacts when enlarged 300 - 500% than did the TIFF or RAW camera formats. My brain says something is not right here, even though I did repeat my test and came up with the same results. It would be a good project for the more ambitious of you out there to run similar tests and confirm, or explain my results. I shot outdoors, on a bright sunny day with the camera on a tripod. Camera was in full auto mode (autofocus & exposure). I tried different focal lengths to test the lens at wide, mid and full zoom settings. I changed the image format between shots to have three identical shots for each focal length. I used the self timer to maximize camera stability.
Even with this setup, I found autofocus problems. Exposure was fairly consistant, and image quality overall was quite good. It was when I enlarged the images in Photoshop 6 and compared the three formats side by side that the image artifacts became noticable. I processed the raw files into both TIFF and JPG. The incamera JPG images showed less artifacts than any other format. Artifacts were most noticable on diagonal lines and fine detail. The artifacts showed up as increased blockiness in the fine detail, with the JPG (incamera) images being less obvious than the TIFF or RAW images. I should point out that the differences were not really noticable at a 1x enlargement of the image.
Summary, I love the image quality of the camera, but strongly dislike the builtin flash's preflash and the autofocus is virtually useless in a situitation where things are happening quickly. Even in a static shooting environment, the autofocus is still a royal pain. With autofocus turned off, the camera performs very well and there is almost no lag time when you press the shutter release. It is still not as fast and responsive as a good SLR, but it comes in a close second. With autofocus on however, responsiveness drops way down as you wait for the autofocus system to make a decision. I still consider the Dimage 7 good value for the (discounted) price. But, if you are looking for the responsiveness of an SLR, look elsewhere.