On Sharpness, ISO and Shutter Speed

Started Nov 29, 2013 | Discussions thread
ProfHankD
ProfHankD Veteran Member • Posts: 6,171
Outlandish reasons for different Horizontal and Vertical Readings

Ok, since this thread has continued so long, I'll add in a couple of outlandish reasons we might see small differences for horizontal vs. vertical readings:

  1. The light-sensitive areas with sensels might not have a 1:1 aspect ratio, perhaps due to paths for wiring. This could lead to slightly wrong interpolation and a small change in effective resolution.
  2. The sensor and lens mount flange might not be precisely parallel. I don't even want to think about this, but absolutely tiny tilts can cause measurable tilting of the focus plane as per the "Scheimpflug principle." This tilt could even be a dynamic function due to shock-absorbing mounting of the sensor.

I'm not saying I think either of these is likely, but they definitely could happen....

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