HaruhikoT Offline Upload & Sell: Off
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Front-End Filter Improves Corner Smearing | |
Update: I found 2.55mm should be fair value as A7\'s cover glass thickness in the simulation.
Lensrentals says a7R\'s Optical Thickness of the sensor stack is 2.55mm:
http://www.lensrentals.com/blog/2014/06/sensor-stack-thickness-when-does-it-matter/
>The sensor optical measurements are made by Brian Caldwell and measure the optical equivalent as if the sensor stack was made of glass with a 1.52 refractile index.
Previously I set the value 1.8mm or 1.85mm, however some simulation results assuming exit pupil distance didn\'t match my field-test experience. So I changed that value to 2.55mm, eventually simulation results (e.g. spot diagrams) look so close to test samples.
I believe 2.55mm suits for all A7 series otherwise genuine FE lenses optimized for the stack must not work.
And this is my latest simulation results:
When you use Summilux-M 35mm ASPH on A7, f=4m PC filter will greatly help corner performance.
Also Kolari / Leica users will get better sharpness with f=8m PC!
Though Opto-sigma\'s lineup is up to 5m, I don\'t know where I can buy 8m PC .
Maybe ZM 1.4/35\'s optimal P-C is also 4m/8m, if its exit pupil distance is same as the LUX35.
Haruhiko
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