Hi,
I just received a new Samyang 20mm f/1.8. I planned to use it mostly for astro, also for landscapes and indoor shots with my K-1 Mark II.
I just did a series of test shot outdoor in order to evaluate sharpness at infinity. Of course, focus was done in Liveview at max. magnification. I am not sure of the quality of my copy.
Here is the result wide open. Exposure was not constant so the lower corners pictures are darker. Oddly f/1.7 is displayed (please look at full resolution):
not very nice, but maybe this is normal for a wide fast lens at this price point? At least, to my eyes there is no obvious decentering of the lens.
Corner and border sharpness does improve to some degree while closed down, but rather slowly. Here is a comparison between center and borders at f/5.6 (please look at full resolution):
For those using this lens on full-frame, do you get similar results ? I may return it but there aren't really alternatives...
thanks,
Dan