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Forums > Back > Just to understand (field curvature and other stuff...)
#11
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?

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#12
It might be or not a good idea in function of the results... 

stoppingdown.net

 

Sony a6300, Sony a6000, Sony NEX-6, Sony E 10-18mm F4 OSS, Sony Zeiss Vario-Tessar T* E 16-70mm F4 ZA OSS, Sony FE 70-200mm F4 G OSS, Sigma 150-600mm Æ’/5-6.3 DG OS HSM Contemporary, Samyang 12mm Æ’/2, Sigma 30mm F2.8 DN | A, Meyer Gorlitz Trioplan 100mm Æ’/2.8, Samyang 8mm Æ’/3.5 fish-eye II | Zenit Helios 44-2 58mm Æ’/2 
Plus some legacy Nikkor lenses.
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#13
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. 
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#14
Quote: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?
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.
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#15
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...
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#16
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".
stoppingdown.net

 

Sony a6300, Sony a6000, Sony NEX-6, Sony E 10-18mm F4 OSS, Sony Zeiss Vario-Tessar T* E 16-70mm F4 ZA OSS, Sony FE 70-200mm F4 G OSS, Sigma 150-600mm Æ’/5-6.3 DG OS HSM Contemporary, Samyang 12mm Æ’/2, Sigma 30mm F2.8 DN | A, Meyer Gorlitz Trioplan 100mm Æ’/2.8, Samyang 8mm Æ’/3.5 fish-eye II | Zenit Helios 44-2 58mm Æ’/2 
Plus some legacy Nikkor lenses.
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