06-29-2012, 08:11 AM
[quote name='jjensson' timestamp='1340915183' post='19236']
This is no field curvature, it's a field triangle. I still don't understand why it isn't mentioned in the photozone test.
[/quote]
The aperture setting + FL + the distance from the focused point are the essentials for dof... And the sensor format for seeing the results on an image for sure... I don't understand how you observed the field curvature (or whatever it is you call it) from these samples you've posted. It's not a good way to check the sharpness of the segments on the 2D image, which are away from each other in the real world, and then tell that somethings is wrong with the lens. The second image for instance (the field), it's obvious that the focus point is in the middle of the frame. And if you draw a horizontal line across the frame, everything is in focus because they're also on the same plane in the real 3D world. But if you draw a vertical line across the frame then you will see that infinity (pardon me Dave <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />) is not as sharp as the foreground. That's not an optical problem as you call it, but an optical fact (dof). The same frame could look quite different (if we pixel peep), incase the focus was set at infinity and the f-stop was ~f/13...
Serkan
This is no field curvature, it's a field triangle. I still don't understand why it isn't mentioned in the photozone test.
[/quote]
The aperture setting + FL + the distance from the focused point are the essentials for dof... And the sensor format for seeing the results on an image for sure... I don't understand how you observed the field curvature (or whatever it is you call it) from these samples you've posted. It's not a good way to check the sharpness of the segments on the 2D image, which are away from each other in the real world, and then tell that somethings is wrong with the lens. The second image for instance (the field), it's obvious that the focus point is in the middle of the frame. And if you draw a horizontal line across the frame, everything is in focus because they're also on the same plane in the real 3D world. But if you draw a vertical line across the frame then you will see that infinity (pardon me Dave <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />) is not as sharp as the foreground. That's not an optical problem as you call it, but an optical fact (dof). The same frame could look quite different (if we pixel peep), incase the focus was set at infinity and the f-stop was ~f/13...Serkan