Minolta DiMAGE 7Hi Review
As with the DiMAGE 7i the 7Hi has two zoom positions for macro focus. The first is at full wide angle (28 mm equiv.) the second is at or near full telephoto (approx. 175 - 200 mm).
Macro Focus: Wide angle
As you can see the wide angle macro focus option provides very little in the way of macro ability. The only thing it does allow for are very close focus distances at the wide angle setting. This could potentially be used to capture a near object in the foreground of a landscape shot.
Macro Focus: Telephoto
Macro focus at telephoto is considerably better. It requires you to have the camera some distance from the subject, but that in itself can make lighting easier. The optimum frame coverage was achieved at full telephoto (200 mm equiv.) and was approximately 55 mm (2.2 in).
Low Light Focus
This test measures the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away.
Light levels are gradually dropped until the camera can no longer focus. This is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).
This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), you should consider the results below the best you could expect to achieve.
|Lens position||Aperture||Lowest light focus|
|Wide angle (28 mm)||F2.8||-1.5 EV (0.9 Lux / 0.08 foot-candle)|
|Telephoto (200 mm)||F4.8||-0.8 EV (1.4 Lux / 0.13 foot-candle)|
Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100) / 10.76391 Lux = 1 foot-candle (fc)
As we expected an identical performance to the DiMAGE 7i, for a camera without an AF assist lamp this is excellent low light auto focus. The DiMAGE 7/7i/7Hi's unique ability to switch CCD output to a high sensitivity black and white mode means that the contrast detect AF system can continue to work at low light levels which would be beyond any other non-AF-lamp digital camera. Kudos.
Pop-up Flash Performance
The DiMAGE 7Hi's pop-up flash has a specified range of approximately 0.5 - 3.8 m (1.6 - 12.5 ft) at wide angle and 0.5 - 3 m (1.6 - 9.8 ft) and telephoto. Generally speaking it performed well, skin tones were natural without any visible colour cast. Flash exposures were well exposed and coverage was as good as we would expect considering the camera's wide 28 mm bottom end.
|Skin tone test: Good exposure, well metered and good colour, no cast.||Wall test: 2m: Good exposure with some drop off in the bottom corners.||Color patch test: Good exposure, well metered with good colour.|
Night exposures / Noise reduction
In an improvement over the DiMAGE 7i the 7Hi now supports timed long exposures of up to 15 seconds at ISO 100. The longest exposure of 30 seconds can be achieved in Bulb mode. Long exposures were noise free (clearly some automatic noise reduction is taking place) and detailed. I'm sure Minolta could have allowed even longer Bulb exposures and even longer timed exposures (up to 5 minutes?).
|F2.8, 15 sec (longest timed shutter)|
|F4.0, Bulb maximum (30 sec)|
Barrel and Pincushion Distortion
Once more (and unsurprisingly) the DiMAGE 7Hi performed identically to the DiMAGE 7/7i in our distortion tests. Considering the zoom range coverage of this lens (28 mm to 200 mm) the lens performs relatively well. At full wide angle you can expect 1.3% barrel distortion and at telephoto you can expect 0.8% pincushion distortion (hardly noticeable).
|1.3% Barrel Distortion at wide angle||0.8% Barrel Distortion at telephoto|
Purple Fringing (Chromatic Aberrations)
As we expected, very little in the way of visible purple fringing. Just as we have observed with the other 7-series Minolta digital cameras this lens does seem to be of very good quality and doesn't exhibit chromatic aberrations.
|Chromatic aberrations in "every day" shots|
|[1/Nov - coming soon]||[1/Nov - coming soon]|
|Our standard chromatic aberration test shot|
Overall Image Quality / Specific Issues
With default image parameters (color, color mode, contrast) the DiMAGE 7Hi produces neutral and well balanced images with low to medium color saturation. Thankfully Minolta provide a good range of parameter adjustment which allows you to 'tune' the final image look to suit your own tastes or final destination. The addition of selectable Adobe RGB color space in-camera is a big boost for this camera and will no doubt raise its profile above some of the competition in the eyes of semi-pro and professional photographers looking for either a compact full-time or backup camera. Resolution also appears to be fairly good, certainly in line with other five megapixel digital cameras but not up at the leading edge (Sony DSC-F717).
The major niggle with the camera, as with the previous DiMAGE 7 cameras (7/7i) and that is noise levels at ISO 100, higher than any other five megapixel digital camera and visible in shadow and mid-tones in many images.
Noise (Mid-tones / Shadows)
In the samples below you can see the typical amount of noise visible in mid-tone or shadow regions and blue skies.
|ISO 100, F6.7, 1/350 sec||100% crop|
|100% crop (full color)||Red channel|
|Blue channel||Green channel|