Minolta DiMAGE 7i Review
Night exposures / Noise reduction
The DiMAGE 7i provides timed long exposures up to four seconds, beyond that you must use the Bulb setting and hold the shutter release button (or use a remote). Long exposures were relatively noise free and clear, indeed it seems a pity that Minolta didn't provide longer timed exposures and a longer maximum Bulb exposure time.
|F2.8, Bulb (approx. 15 sec)|
|F2.8, Bulb maximum (30 sec)|
Barrel and Pincushion Distortion
Not surprisingly the DiMAGE 7i performed identically to the DiMAGE 7 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. Further evidence that the DiMAGE 7i's lens is of a very good quality especially when you consider the wide zoom range it covers.
|Chromatic aberrations in "every day" shots|
|Our standard chromatic aberration test shot|
Overall Image Quality / Specific Issues
Overall the DiMAGE 7i produces well balanced and exposed images with good resolution. The adoption of a more 'sRGB like' colour space means that images can now be used with more confidence straight out of the camera. The lens appears to be sharp and without any major faults. There is no doubt that the 7i can take great images which will look good at monitor resolution and in print. However, one niggling issue must be the amount of noise visible in even well exposed, low sensitivity (ISO 100) shots.
While I have not been able to carry out direct side-by-side comparisons it seems fairly clear to me that the DiMAGE 7i exhibits higher noise in shadows and deep blue skies than its predecessor the DiMAGE 7. We are used to seeing noise at higher sensitivities (ISO equiv. values) but with the 7i noise can be seen even at ISO 100 (see below). These noise levels are higher than we would expect of a 5 megapixel digital camera and are definitely higher than some of the competition notably the Nikon Coolpix 5000 / 5700 and Sony DSC-F707.
In the samples below you can see the typical amount of noise visible in shadow regions or deep blue skies. Both exposures shown below were taken at ISO 100.
Noise visible in blue skies
|Red channel||Green channel|