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How to read MTF charts
#1
Can I ask Klaus to explain me how to read the resolution charts? In other terms, when I look at the Leica Summilux 25mm f/1.4 MTF and read 2658 LW/PH at f/2, what that means in terms of L/mm? Should I divide that number by the height of the sensor which is 13,5mm or should I divide it by 25,4 assuming that the value refers to an height of 1" ? Considering that the circle of confusion for a good eye is about 4-5 L/mm at 25 cm distance, this converts into 60-70 L/mm on the 4/3 sensor which should be considered as a sort of decence threshold for a good lens, is that right ?



Now, when I look at an MTF chart of a full frame lens such as the Nikkor AF-S 24-70mm f/2.8G ED (FX) at 24mm f/4, I read 3988 LW/PH. If I convert this number using the picture height of a FF sensor I will divide it by 24mm and will get 166 L/mm which is almost twice the resolution of the Leica (I don't think this is correct). On the other hand if I divide it by the unit (1") I will still get an impressive 157 L/mm (still unrealistically higher than the Leica). Where is the error in my assumptions?



Thank you

Carlo Borra
  


Messages In This Thread
How to read MTF charts - by Guest - 11-18-2010, 09:32 AM
How to read MTF charts - by mst - 11-18-2010, 10:36 AM
How to read MTF charts - by Guest - 11-18-2010, 02:25 PM
How to read MTF charts - by Guest - 11-18-2010, 07:15 PM

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