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Autofocus Inconsistency, Backfocus, Manual Focus

Like many mirrorless cameras, the Leica X Vario has a fundamental algorithmic flaw in its autofocus: it focuses with the lens stopped down to the shooting aperture. Compare that idea with opening the lens diaphragm to focus precisely, then shooting at the stopped-down aperture (as with all DSLR cameras).

This stopped-down autofocus algorithm not only affects focus accuracy, it actively degrades autofocus performance as the lighting dims, a problem I encountered repeatedly in the field. At times, the focus was unable to lock on at all unless I opened the aperture fully.

With the lens stopped down, a deeper zone of sharp focus is obtained (depth of field), and the camera cannot then distinguish the optimal focus, with the result that the near-far positioning of the zone of focus can be skewed in undesirable ways: a blurry foreground and too-sharp background or vice versa—all while the chosen point of focus is just as sharp either way (or maybe not, as we shall see).

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Diglloyd Guide to Mirrorless offers comprehensive integrated coverage of most APS-C and full frame mirrorless cameras and lenses.

Special emphasis is placed on Sony full-frame, including Sony lenses and the high performance Zeiss Batis and Zeiss Loxia lenses plus Rokinon/Samyang and others. Fujifilm X, Olympus and Panasonic M4/3, Sigma dp Merrill and dp/sd Quattro are also covered in depth. Years in the making, it offers a wealth of material for choosing and using a mirrorless camera.

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  • Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
  • Optical quality analysis of field curvature, focus shift, sharpness, flare, distortion, and performance in the field.

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