| Review statistics for buster2015 | | | Lenses Added | 1 (View Lenses Added) | | Reviews Posted | 14 (View Reviews) | | User's Lens View Count | 3,504 | | Latest Lens Addition | 
Steinheil München Auto-D-Tele-Quinar 135mm F2.8 | | Latest Review Posted | Samyang 10mm F2.8 ED AS NCS CS
My rating on sharpness is based on this lens's performance on the 16MP sensor of K-01/K30. Center sharpness is very good even wide open and becomes excellent after closing down 1-2 stops. Corner sharpness is a strange thing. When center is focused, corner sharpness is not so good at f2.8 but improves to very good at f5.6. I found that I can adjust the focus of the lens to make the corners very good at f2.8 and excellent at f5.6, but then center became blurry. Given that in my test the center and the corners are nearly flat, my guess is that this lens, or at least my sample, has a very strong field curvature. So when I look for uniform sharpness across the frame I close the lens down to f5.6 and below - everything then becomes (more than) acceptably sharp.
To put the performance of this lens in perspective, I can make reference to Sigma 10-20/3.5. Wide open the Sigma is a bit sharper in the center. In the corners this Samyang is MUCH better. Sigma needs to be closed to f11 at 10mm to have acceptably sharp corners - still they look worse than Samyang at f5.6.
As someone has already mentioned it is a challenge to focus this lens. On K-30 the in-focus prompt helps but I've found live view + focus peaking to be the most reliable. | |
