EXCERPT page containing first few paragraphs. 2019-05-25 11:16:43
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Discussions of lens bokeh (rendering style) often focus on details: color aberrations, smoothness of edge transitions and similar small-scale effects. But overall bokeh is hardly ever discussed, yet it exerts the strongest effect on the visual impact of an image.
A key overall aspect of bokeh (at least for some subjects) has much more to do with the overall rendering across the frame. That is where field curvature plays a key role: the visual impact of an image can be degraded by sharpness appearing in odd places: blurred at center and sharper at the edges at varying distances; it undermines the separation of subject from background.
A non-uniform sharpness gradient (field curvature) can be used to good effect, but it is a dual-edge sword. The worst offender is undulating (wave type) field curvature (often found with f/1.4 wide angle lenses), the most tractable is a simple rearward or forward field curvature: easy to understand and thus learn to exploit to good effect, or to mitigate, depending on the subject. Many excuses are made that field curvature is “just fine“ for some uses (the “mystique factor”). While field curvature can be used to good effect, it is also true that a flat field lens is strongly preferable for most all photography: no mitigation strategies are needed and no mental gymnastics are required to understand where sharpness will be delivered.
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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.
- Make better images by learning how to get the best results right away. For example, the best way to set up your Sony camera.
- Save money by choosing the right lens for your needs the first time, particularly with the numerous lenses available for Sony.
- Make better images, a sort of “cheat sheet” saving yourself months or years of ad-hoc learning—best practices and how-to and processing parameters are discussed and shown.
- Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to full camera resolution, plus large crops.
- Real world examples with insights found nowhere else. Make sharper images just by understanding lens behavior you won’t read about elsewhere.
- 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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