DIY:
http://focustestchart.com/chart.html
或者买现成的:
http://www.outdoorphotographer.com/columns/solutions/af-fine-tuning.html
DIY:
http://focustestchart.com/chart.html
或者买现成的:
http://www.outdoorphotographer.com/columns/solutions/af-fine-tuning.html