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Nikon D800
Nikon D800

Focus Accuracy (Focus Assist with Green Dot)

Examples on this page were all taken handheld, with the goal of establishing how well the Nikon D800 focus assist feature (“green dot”) works for manual focus accuracy, e.g., with the Zeiss ZF.2 or other manual focus lenses.

I chose a variety of subjects with different lighting and details in order to get a sense of how well AF-assist works; this is very much a field test, which I consider more revealing and useful than a “scientific” lab test. A lab test of focusing constrains parameters (lighting, subject matter, contrast, etc) so much as to have little relevance to making images in the field.

The precision required for accurate manual focus means that many autofocus lenses are borderline unsuitable for reliable manual focus because of the twitchy and hyper responsive focusing rings (I have one AF lens that shifts focus simply by lifting my hand off the lens!). Good manual focus lenses (e.g. Zeiss) have focusing helicoids, an important consideration for manual focus operation.

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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.

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ƒ/2 @ 1/3200 sec handheld, ISO 100 + 0.66 push
Nikon D800 + Zeiss 100mm f/2 Makro-Planar

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