7th March 2005, 08:26 PM
MTF charts...how to read?
Can someone please explain to me how the MTF chart works? I suck at graphs. :P Thanks.
7th March 2005, 09:24 PM
Hmm... not too sure myself, especially on what the various lines mean, but the idea is something like, the more those lines remain on the high side of the y-axis throughout the entire x-axis, the better...
the y-axis basically represent the output of the lens given a fix amount of input(light), and the x-axis basically represent how far from the center of the lens the measurement represent. therefore as you notice, majority of those consumer lens suffer sharpness+contrast hits toward the far out edges of the lens, and when you look at the respective MTF chart of those lens, you will find that at the far right of the x-axis, the lines fall pretty low on the y-axis. And of course with most primes where sharpness+contrast is superb throughout the entire pic from center to the sides, their respective MTF chart would be having all the lines on the high side of the y-axis for the entire streach of the x-axis.
Hmm... and yea, from what I observed, since the x-axis measure the output of different area of the lens and the right most is the furthest from the center of the lens, most EFS lenses will have a smaller value on the x-axis on their MTF chart as compare to EF lenses because they have a smaller output image circle...
yea, something like that... please correct me if I am wrong...
7th March 2005, 09:26 PM
ideal MTF curve should be a horizontal line
8th March 2005, 07:08 PM
uhuh...i think i vaguely get it now. thks guys!
8th March 2005, 07:51 PM
You can read the section on 'Understanding the MTF graph' @ http://www.photodo.com/nav/artindex.html
9th March 2005, 01:46 AM
Thanks for the link.
Originally Posted by chenchengcai