Test: Bronica PS40mm soft wide open

Hi all,

the attached image was shot at 4.0 with a Bronica PS 40mm at f4.0. No unsharp mask was applied.

The corners are terrible - distorted and blurred.

http://www.flickr.com/photos/90448738@N05/11999266343/lightbox/

For those with more experience with this lens, at what aperture should be lens be shot for acceptable corner sharpness?

I bet something like f/6.3 would be decent. I haven't used mine too much.

I'd suggest finding another sample photo to judge sharpness. That photo is not well suited for the task.