ZS30 with iRes/iZoom

 

Earlier I had examined how iResolution and iZoom operate on the ZS20/TZ30, as described here.


While the ZS30TZ40 has the same lens as the ZS20/TZ30, it has a different sensor (with 18MP rather than 14MP) and different JPG processing.  Therefore I conducted tests to determine whether iResolution/iZoom on the ZS30/TZ40 shows any improvement over the ZS20/TZ30.


The ZS30 manual gives exactly the same information about iResolution and iZoom as does the ZS20 manual, and the functions seem to operate in the same way as before.  Because I had previously determined that it was preferable not to use iResolution at zoom settings below 20x, I tested the ZS30 at 20x (480mm FL) only. 


At maximum optical zoom (20x, 480mm) having iResolution switched on has the same effect as having iZoom switched on, as explained and demonstrated for the ZS20.  I carried out tests with my ZS30 using a tripod and the same chart setup as described previously. 


I took duplicate shots with iResolution OFF and iResolution ON, and I repeated the tests at 100, 200, 400 and 800 ISO settings.


I took central crops from the images as previously, showing the Es chart; portion of the magazine photograph of Birtinya Island; and the narrowing lines chart.  On-screen, side-by-side at 300%, I compared each of these crops from duplicate images for iResolution ON and OFF, and prepared JPG images from the comparisons.  I prepared comparisons for each of the ISO settings tested, and these are shown below (click on an image to see the full sized view).


Es chart at 100 ISO, 480mm, f/6.4: iRes ON and OFF


Es chart at 200 ISO, 480mm, f/6.4: iRes ON and OFF


Es chart at 400 ISO, 480mm, f/6.4: iRes ON and OFF


Es chart at 800 ISO, 480mm, f/6.4: iRes ON and OFF


Magazine photo at 100 ISO, 480mm, f/6.4: iRes ON and OFF



Magazine photo at 200 ISO, 480mm, f/6.4: iRes ON and OFF


Magazine photo at 400 ISO, 480mm, f/6.4: iRes ON and OFF



Magazine photo at 800 ISO, 480mm, f/6.4: iRes ON and OFF



Narrowing lines chart at 100 ISO, 480mm, f/6.4: iRes ON and OFF



Narrowing lines chart at 200 ISO, 480mm, f/6.4: iRes ON and OFF



Narrowing lines chart at 400 ISO, 480mm, f/6.4: iRes ON and OFF



Narrowing lines chart at 800 ISO, 480mm, f/6.4: iRes ON and OFF



Discussion


Examining the above crops at 300% showed that at 100 ISO, as previously observed with the ZS20, there was a slight noise reduction effect, and slight sharpening with iRes ON versus iRes OFF.  However, the sharpening observed with the ZS30 was less severe than for the ZS20, which had shown artifacts (white haloes) indicative of over-sharpening.  As with the ZS20 there was slight smearing and slight loss of very fine, low contrast detail for the ZS30 with iRes ON when viewed at high magnification.  This can be seen most clearly around the 26 region in the comparison of the narrowing lines chart crops, and the detail of the white buildings in the photograph crops.


The effect of the noise reduction with iRes ON was somewhat more evident in the 200 ISO images, and is most visible in the white background of the Es chart crops.  The NR effect did however lessen as the ISO setting was increased above 200 ISO.  At 400 ISO it is hard to see any significant change in the white background of the Es chart with iRes ON, but there is still a slight visible increase in definition/contrast of the Es.


Conclusion


While the effects of iResolution/IZoom are similar for the ZS20 and the ZS30, there appears to be better processing in the ZS30 which avoids the oversharpening effect of iResolution.  There is also a slight NR effect with iResolution ON vs OFF that is visible at 100 and 200 ISO settings.  While there is a slight accompanying loss of fine, low contrast detail with iResolution ON vs OFF, the difference is only visible at high magnification, and at normal viewing sizes it is probably not significant for most purposes.




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