Chapter 3
Leica | 6 |
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Flare and secondary images are absent and specular highlights in the blazing sun are free from halo effects.
Vignetting may be visible under critical circumstances (wide open), but it is eliminated at f/5.6.
100[%] |
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80 |
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| 8.0 |
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| 5.6 | |
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| 2.8 |
60 |
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40 |
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20 |
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0 |
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0 | 5 | 10 | 15 | 20 |
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| Y'[mm] |
Distortion amounts to 1% in the comers and may be visible when one photographs geometric figures (architectural details) near the edges of the negative.
Y'[mm] |
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12 |
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9 |
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6 |
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3 |
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0 |
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0 | 3 | 6 | 9 | 12 | 15 | 18 |
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| X'[mm] |
The high level of correction of the current 180 mm lens can be seen in the MTF graphs. The f/2.8 aperture delivers the best performance, it might be improved a bit at f/4, but at f/5.6 you already see a small reduction in contrast, which is even more pronounced at f/8.
100[%] |
| Aperture Stop 2.8 |
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| 1 | |
80 |
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60 |
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40 |
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20 |
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0 |
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0 | 5 | 10 | 15 | 20 |
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| Y'[mm] |
100[%] |
| Aperture Stop 5.6 |
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80 |
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60 |
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40 |
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20 |
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0 |
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0 | 5 | 10 | 15 | 20 |
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| Y'[mm] |
100[%] |
| Aperture Stop 8.0 |
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80 |
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60 |
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40 |
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20 |
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0 |
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0 | 5 | 10 | 15 | 20 |
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| Y'[mm] |