A useful first step in testing a lens is shooting a resolution chart, or any target with lots of high-contrast fine detail. diglloyd uses the Sleicher resolution chart because it provides high contrast detail at varying resolutions, angles, and positions. A resolution chart reveals basic performance characteristics of the lens, including its sharpness, contrast, color fringing and distortion.
No conclusions should be made solely on the basis of results from a resolution chart. When shooting a planar target like a resolution chart, the following caveats should be kept in mind:
1. Focus distance. diglloyd uses a 3 X 2 foot resolution chart. The chart is framed so that it fills the frame. A lens may or may not perform at its best at this focusing distance; performance could change significantly when focused at infinity. The Schneider 28mm/f2.8 PC Super Angulon incorporates a floating lens group to enhance performance at close-focusing distances; it can be expected to out-perform the Nikkors at close distances because of this optimization.
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Since 2006, Diglloyd Advanced Photography is the authoritative review and reference for DSLRs and their lenses: Canon and Nikon primarily, but also Pentax and some medium format. Reviews of key DSLRs are included, but the primary focus is on lens performance. Also included is a wealth of technique and workflow approaches.
DAP includes thousands of pages of exclusive coverage and high resolution Retina-grade examples detailing Canon and Nikon DSLR bodies and their lenses, with in-depth analysis of sharpness and contrast, color, bokeh, vignetting, distortion, MTF, and flare, behavioral and practical usage.