Even at the full aperture there is a remarkable sharpness throughout most of the frame.
At the optimum aperture, f/8, the lens performance is only a little better, showing maximum sharpness in 3 center charts (resolution of "37" is the max. theoretical number in this test). There is about 1.6% reduction of the circle size at the sides of the frame compared to the circle size at the center. At the 21st mm the circles become ellipsoidal, with a 2% difference between the extreme diameters. Also note a variable resolution, depending in which direction you read the lines, especially on the 18 and 21st mm chart. This aberration mimics the moved camera effect, but only on the sides. Chromatic aberration is small.
Analysis at the focal length of 130 mm at various f stops is given here. The best performance is at f/8. Dependence of the image quality in various parts of the full 24x36mm frame is shown below, with the average resolution in hundreds of line widths per picture height (LW/PH) given below each chart.
Even at the full aperture the lens is very sharp (resolution of "37" is the max. theoretical number in this test). There is a 1.5% increase of the circle diameter at the sides of the frame compared to the circle size at the center. At the sides the circles look elongated slightly, with a 1.6% difference in the extreme diameters of the ellipse. Remarkably, there is almost no chromatic aberration.
Analysis at the 200 mm at various f stops is given here. The lens is the softest at this focal length, with the best performance at f/5.6 and f/8. Dependence of the image quality in various parts of the full 24x36mm frame is shown below, with the average resolution in hundreds of line widths per picture height (LW/PH) given below each chart.
At this focal length the lens sharpness is still good, but it is the the lowest than at the other two lengths tested. There is a 2.7% increase of the circle diameter at the sides of the frame compared to the circle size at the center. At the sides the circles are elongated, with a 4.2% difference in the extreme diameters of the ellipse. It is clearly visible, and high when compared to similar focal length lenses. Chromatic aberration is low. Good contrast overall.
