07-26-2015, 07:33 AM
Two things: I know I have been wrong about some theories in the past and I'm afraid, I will occasionally be wrong in the future. Making mistakes is part of evolution.
The other thing is: I'm a customer of a manufacturer who happens to be the same way. Nikon had some issues in the past and I often thought why didn't they test it, thought of it?* One of them was a misaligned AF module in D800, which has nothing to do with field curvature but made very clear, how fragile this whole indirect phase AF model is with HR sensors and lenses used wide open. Even with no movement of camera and target, I don't get 100% accuracy of each attempt to focus - and that is for the center AF, which usually is the best place.
Klaus hasn't replied to my question, wether he used PDAF or CAF (or no AF at all?) It doesn't matter much. The sample clearly shows "take care with focusing when using a lens wide open in front of a 50 MP sensor" Nikon had to learn that, and I don't know if Canon got it right from the beginning and has a 100% reliable assembly line. Also, I've the impression there are more "issue-seekers" on the Nikon side, less so Canon users.
Just checked quickly, about 11% of my pictures I took at aperture f/1.8 or wider open. Don't know about your rate, guys. Of course that doesn't affect if you're right or wrong. I think you're referring to the theory and I was mislead with the field curvature idea. I just often found real life doesn't care much about theoretical assumptions. So if it's not field curvature, there are still other possibilities to miss focus far out of the image's center.
* One answer could be "otherwise they wouldn't have come out with 36 MP 3 years ago". Extensive testing only includes the scenarios the tester would found to be critical. All users together ask for much more than a couple of testers could think of.
The other thing is: I'm a customer of a manufacturer who happens to be the same way. Nikon had some issues in the past and I often thought why didn't they test it, thought of it?* One of them was a misaligned AF module in D800, which has nothing to do with field curvature but made very clear, how fragile this whole indirect phase AF model is with HR sensors and lenses used wide open. Even with no movement of camera and target, I don't get 100% accuracy of each attempt to focus - and that is for the center AF, which usually is the best place.
Klaus hasn't replied to my question, wether he used PDAF or CAF (or no AF at all?) It doesn't matter much. The sample clearly shows "take care with focusing when using a lens wide open in front of a 50 MP sensor" Nikon had to learn that, and I don't know if Canon got it right from the beginning and has a 100% reliable assembly line. Also, I've the impression there are more "issue-seekers" on the Nikon side, less so Canon users.
Just checked quickly, about 11% of my pictures I took at aperture f/1.8 or wider open. Don't know about your rate, guys. Of course that doesn't affect if you're right or wrong. I think you're referring to the theory and I was mislead with the field curvature idea. I just often found real life doesn't care much about theoretical assumptions. So if it's not field curvature, there are still other possibilities to miss focus far out of the image's center.
* One answer could be "otherwise they wouldn't have come out with 36 MP 3 years ago". Extensive testing only includes the scenarios the tester would found to be critical. All users together ask for much more than a couple of testers could think of.