Trevor Sowers wrote:
Yes when it is wide open you need to keep the subject within the area of the focus points on a 5D MKII. Once stopped down to 2.8 though it is quite good over most of the frame and at f/4 it is all good except for the very corners.
That's about my experience with it.
As I recall, there is noticeable improvement towards the edges by going from f/4 to f/5.6.
Snopchenko wrote:
Ah, Trevor, good that you chimed in. I was about to perform a summoning ritual. I remember you explaining the subject to me (and a few others who were interested) in the previous round of "28/1.8ish" threads.
AFAIR the center sharpness of this lens gets a big boost at f/2 - f/2.2.
"One could also argue that shooting a wide open at f/1.8, 99% of the time the subject is in the center of the frame anyway, and the poor edge performance actually assists in isolating the central subject."
Unless you are shooting night sky images of stars, in which case you're sunk of course. Even my beloved 24L mk 2 really needs to go down to f2.8 before the corners are good. It would be nice to have a fast 28 with good corners wide open. Note I said "good" not "incredible".
Ken Rockwell was ecstatic about Nikon 28/1.4 but it's a rare and discontinued lens. Also it's a Nikon after all, and Ken Rockwell is not always spot on in his reviews.
I used the Nikon 28/1.4 as my main lens for more than a decade. It was a wonderful lens for its time, and I would be very surprised if it didn't totally smoke the Canon 28mm f1.8 at wider apertures.
Having said that, although I never had my Nikon 28/1.4 at the same time as my Canon 24L Mk2, I am sure that the Canon lens was definitely better on a FF body. Not suprising as the Canon is nearly 2 decades younger and uses nano technology that wasn't available in the good old days.
I've Sigma 30mm F1.4 and use it as my primary lens along with Canon 85mm F1.8 on my Canon 60D. Results are pretty good with it.
Here is one of my favoraite using 30mm