edwardkaraa wrote:
This issue is a bit strange, because as far as I know, and please correct me if I\'m wrong, corner smear and color shift are related, and are caused by the same phenomenon, being the oblique light rays being distorted by the sensor glass cover and spilling to neighboring sensels, causing both the smearing and the color shift. Offset micro lenses and thinner glass cover jointly work on correcting both issues. (I know smearing is associated more with the glass cover, while the corner shift more with the light spilling, but it\'s not clear cut). So why should the 7 perform better with RF lenses? And if it does, I would expect less smearing too.
I think it\'s two separate issues:
#1: The thickness of the glass cover introduces astigmatism and/or a curved field, which gives \"smearing\".
#2: Light hitting the microlenses \"misses\" the intended photosite and spreads over to the wrong places, which gives color casts towards the corners and borders.
Number two is not really an optical phenomenon, since it occurs behind the glass cover, while number one is distorting the properties of the optical system; the lens.
So, if this is true, it makes sense that the a7 gives less shift and the a7r gives less smearing.
Edit: If the glass really is thick, the light will hit the photosites at a steeper angle behind it and therefore probably cause less shift.
edwardkaraa wrote:
This issue is a bit strange, because as far as I know, and please correct me if I\'m wrong, corner smear and color shift are related, and are caused by the same phenomenon, being the oblique light rays being distorted by the sensor glass cover and spilling to neighboring sensels, causing both the smearing and the color shift. Offset micro lenses and thinner glass cover jointly work on correcting both issues. (I know smearing is associated more with the glass cover, while the corner shift more with the light spilling, but it\'s not clear cut). So why should the 7 perform better with RF lenses? And if it does, I would expect less smearing too.
I think it\'s two separate issues:
#1: The thickness of the glass cover introduces astigmatism and/or a curved field, which gives \"smearing\".
#2: Light hitting the microlenses \"misses\" the intended photosite and spreads over to the wrong places, which gives color casts towards the corners and borders.
Number two is not really an optical phenomenon, since it occurs behind the glass cover, while number one is distorting the properties of the optical system; the lens.
So, if this is true, it makes sense that the a7 gives less shift and the a7r gives less smearing.
Oct 30, 2013 at 01:02 PM
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