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Resolution Chart ComparisonComparison cameras:
Shots here are of our standard resolution chart (version one or two). This chart allows us to measure the actual performance of the lens and sensor system. It measures the ability of the camera to resolve lines at gradually higher resolutions and enables us to provide a definitive value for comparison purposes. Values on the chart are 1/100th lines per picture height. So a value of 15 equates to 1500 lines per picture height. (Note that on version two of our chart the vertical resolution 1000 - 2000 lines have been horizontally flipped but are otherwise identical). For each camera the relevant prime lens was used. The chart is shot at a full range of apertures and the sharpest image selected. Studio light, cameras set to auto, settings all factory default. If possible aperture was selected for optimum sharpness. Exposure compensation +0.3 EV to +1.3 EV.
Resolution chart crops
Measurable findings
Proof, were it ever needed, that any advantage to be gained by moving from 7 to 8 megapixels is dubious to say the least; no matter how many times we re-tested the EX-Z850 it produced marginally lower resolution than its predecessor, the EX-Z750. Given both cameras have the same lens (which is probably the limiting factor, resolution-wise) we might have expected the results to be the same, but there is no denying that there is a little more very high frequency detail in the 7MP image. We suspect the limiting factor here is noise - the 8MP chip needs a little more noise reduction even at ISO 50, and though you'll rarely see it in real-world shots, this does have a blurring effect on very fine detail. The higher contrast and higher sharpening of the Z750 image also makes the image look more detailed, though as we are talking about frequencies very near to Nyquist I doubt there is any real difference in resolution - you'll just get sharper 'looking' fine detail with the Z750. Comparisons with its predecessor aside, the EX-Z850 is producing fairly clean results (though there is a little evidence of sharpening), and the images are clean, moiré-free and have resolution that puts them in the top half (though not at the top) of the current crop of 8MP compacts. |
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