Lens review
2009-05-12
Samyang 8 mm f/3.5 Aspherical IF MC Fish-eye
7. Coma and astigmatism
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Shooting a diode and moving it towards the corner of the frame is very difficult in case of a fisheye so this time, we used the night sky instead. Stars, visible as points, do well for testing optical aberrations . As we can see, coma is not much of a hindrance. It is visible at f/3.5 but becomes marginal as we stop down to f/5.6.
The situations is similar when it comes to astigmatism. It is not completely invisible and it gets in our way at maximum aperture but its average level amounting 6.3% is not bothersome.
