How apt interpret the legislature of indicatoapt t

MTF = modulus of transmit feature

MTF test is the most accurate and technological method of lens testing. Sweden the authority of the dark and pearly lines brand the gradual transition embark, through the projection lens. was the result of measurement is the abatement of compare among the situation. If the resulting image compare and the same test target, the MTF value of 100%. This is the best lens ideal in truth do not exist;

in half if the contrast,Womens Lacoste Trainers New, the MTF value of 50% .0 represents the absolute wastage of contrast, black and white lines was diluted to a unattached gray.;

while value exceeds 80% (20lp/mm below) already very good; the value of less than 30% even now the next film in the 4X6-inch enlargements image quality is still poor.

test points to the two kinds of radial and tangential direction. If the difference between the two larger,Lacoste Arin Patent Trainers, more solemn subject that the lens astigmatism. higher spatial frequencies (ie lp / mm value,Lacoste Running Trainers, understood as resolution) as 30lp/mm and 20lp/mm compared to the MTF values ​​are generally lower.

Note: The contrast here the performance of the screen's performance is equivalent to what we call called inconsistency (2.5%!) can also be reflected in the picture!

you can look it as a elementary mm meantime for radial and tangential than 95%. less than 90%, or that the poor performance of the lens.

a clear difference between sharpness good and sharpness sharpness of the lens is usually worse than the Ming and high sharpness The camera looks sharper! However,Lacoste Trainers 2011, sharpness and sharpness of the two arrows are usually complementary to each additional out.

Sharpness: 10 to 40 (or higher) lp / mm lens sharpness that 1 - that the aptitude to reproduce the details of the forgery of the thing lens .40lp/mm that very fine details (such as portrait photography in the cilia) of capacity. At this point even now the big breach between the MTF values ​​(eg 10%) can not be directly recognizable in the picture. aptitude to distinguish along to the person eye and 35mm membrane in medium format, if you ambition to get very good quality 7-inch photos, the lens 20lp/mm value have to be greater than beneath the 50% MTF. However,Lacoste R75 P2 Trainers, if we are still in very good below 16 inches picture quality, its 70lp/mm really be beneath the MTF value of extra than 63%! about no lens can achieve such a good performance!
uncomplicated rules to identify the lens (2 tranches receive a small hole):

40lp/mm curve (ruddy) shall be situated
edge of> 20% (plot right)
Center> 65% (graph on the left).
20lp/mm curve (violet) to be located at:
edge of> 45%
center> 80%
10lp/mm curve (green) to be very close to the 5lp/mm curve.
5lp/mm curve (blue) shall be the whole X-axis ashore the ultra wide-angle lens above the edge of the picture quality tin no be demanding.

tangential curve in most cases is lower than the upon criterion. And the value of the radial curve is relatively high.

Note: lens utmost aperture (ie, fewer than the highest aperture and f/16) the respective penniless performance! their values ​​do not characterize the optical lenses can achieve the best quality! best aperture is routinely smaller most aperture closing 2-3 files.
sharpness and contrast


field figure underneath the curtate axis represents the radius (distance from the megalopolis), perpendicular axis represents the percent of the value of MTF, dashed solid lines represent the radial and tangential values.

Canon EF 85mm/F1.2L at f/5.6:

outstanding performance - Ming sharpness and sharpness is splendid!



Canon EF 20mm/F2 .8 USM at f / 8:

out the details of sharpness is relatively agreeable, yet limited capability to reproduce (cut to the 40lp/mm)



Sigma AF 28-70mm / F2.8-4.0 at 70mm f / 8:

good sharpness, but poor sharpness Ming (5lp/mm worse than 90%)



Sigma AF 28 -70mm/F2.8-4.0 at 28mm f/2.8 (full aperture):

poor performance - if it is remove sharpness or sharpness,Lacoste Trainers UK!