The Resolution of the P900

 


Variation of Resolution with ISO and Aperture


I tested the P900 at 95mm EFL using the resolution charts designed by Dr J. C. Brown, as described here.  On the chart board I included both the coloured Es chart I had used previously and the more recent black stepped lines chart.  The camera was mounted on a tripod and the chart board was illuminated by diffused light from two daylight (5500º K) lamps. For these tests I used the “Neutral” picture setting.  On the chart board I included other materials to provide additional means of showing changes in IQ and noise.  Below is a test chart image taken at 95mm EFL, f/4 and 100 ISO.  (Click on the image for the full sized view.)



Chart board with 4cm resolution charts, 95mm EFL, f/4, 100 ISO, Neutral


Aperture Series


I compared chart images taken at 95mm EFL and 100 ISO for each available aperture setting from f/4 to f/8.  A comparison of crops of the Es chart at each aperture is shown below. (Click on the image for the 100% view.)



Comparison of 100% crops from test images taken at each aperture setting


It can be seen that a slight deterioration in IQ due to diffraction starts to become evident at about f/7.1 and is more evident at f/8.  This is the usual trend for 1/2.3” sensors with small sized pixels.


ISO Series


I compared chart images taken at 85mm and f/4 at each ISO setting from 100 ISO to 6400 ISO.  A comparison of crops from two different areas of the chart board are shown below (Click on the image for the 100% view.)



Comparison of 100% crops from images taken at each ISO setting - Area 1



Comparison of 100% crops from images taken at each ISO setting - Area 2


It can be seen that the image noise increases gradually from 100 ISO to 1600 ISO and that noise causes a serious loss of image detail at 3200 ISO and 6400 ISO.



I further tested the resolution of the P900 at a range of focal lengths up to 2000mm, as described on the following page.





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