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+--- Thread: Just to understand (field curvature and other stuff...) (/showthread.php?tid=1591)
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Just to understand (field curvature and other stuff...) - Brightcolours - 01-15-2014
With a curved focal plane corners are not unsharp. They are just sharp at a different plane.
Some logic: one usually focusses on the subject or a main attraction in the scene. What you are proposing is intentionally back focussing the main subject or intentionally front focussing the subject in order to get the corner focal plane closer to the subject focal plane. Does that sound like a good idea?
Just to understand (field curvature and other stuff...) - stoppingdown - 01-15-2014
It might be or not a good idea in function of the results...
Just to understand (field curvature and other stuff...) - Guest - 01-15-2014
Quote:Perhaps between the optimal focus at the center and the optimal focus at the corner there's a point in which the center is just less sharp and the border more acceptably sharp.
yes, that's what I tried to explain, try to find an acceptable point in between.
Just to understand (field curvature and other stuff...) - Guest - 01-15-2014
Quote:With a curved focal plane corners are not unsharp. They are just sharp at a different plane.For some, who want to have the same sharpness across the whole field, even taking into account stopping down, it may be what they want to do.
Some logic: one usually focusses on the subject or a main attraction in the scene. What you are proposing is intentionally back focussing the main subject or intentionally front focussing the subject in order to get the corner focal plane closer to the subject focal plane. Does that sound like a good idea?
Just to understand (field curvature and other stuff...) - Brightcolours - 01-15-2014
Quote:For some, who want to have the same sharpness across the whole field, even taking into account stopping down, it may be what they want to do.They then will get substandard results (much like hyper focal distance adepts). The question was if any camera can compensate for field curvature of the lens, and the question then still must be a no. A camera user can do whatever he/she pleases, of course...
Just to understand (field curvature and other stuff...) - stoppingdown - 01-17-2014
Quote:They then will get substandard results (much like hyper focal distance adepts). The question was if any camera can compensate for field curvature of the lens, and the question then still must be a no. A camera user can do whatever he/she pleases, of course...
Why necessarily substandard? I'm just speculating, of course, but if I think e.g. of a 16MP sensor and a lens with high center sharpness, couldn't the perfect center focus spot over-resolve the sensor? In this case, a slight back- or front-focusing perhaps wouldn't degrade the center performance.
"Compensate" is probably an inappropriate word. I could rephrase with "mitigate".