EXCERPT page containing first few paragraphs. 2019-08-24 16:36:22
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See also View to Mt Whitney From Alabama Hills, which confirms this behavior.
This series assesses the Fujifilm GF 63mm f/2.8 at distance, and expressly shows the problematic lack of focusing precision that one can expect from the Fujifilm GFX. The variability shown here was observed over and over in the field, a great source of aggravation. The greatest problems occurs at distance, as here, where precision is at its worst and where tiny changes in focus can make a big difference.
Precision and accuracy are scientific terms:
- The precision of a measurement system, related to reproducibility and repeatability, is the degree to which repeated measurements under unchanged conditions show the same results. For focusing, one wants to see the same focus every time, given the same subject matter.
- The accuracy or trueness of a measurement system is how close the actual value is to the true value. For focusing I call this true value “optimal focus”.
- A measurement system can be accurate but not precise, precise but not accurate, neither, or both.
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These systems are hugely expensive, so make the right choice for your own needs (full frame vs medium format).
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