Lens review
2009-10-27
Leica Summicron-M 50 mm f/2.0
7. Coma and astigmatism
The not-so-good image resolution at the edge of the frame becomes understandable when we look at the level of coma correction. At the maximum aperture its influence on decreasing the resolution is large. Fortunately, after stopping down by one aperture value the problem becomes smaller and after stopping down by 2 EV practically vanishes.
When it comes to astigmatism, its level’s been measured to be about 9%. It may not be a large value, but we might expect a little more of this producers equipment.
