Sharpness transition

LucisPictor · Expire: 2013-12-03

Hi!

I recently have read some nice thoughts about sharpness transition.

Fig. A

In #1 you see the ideal case, the tip of the cone will be located exactly at the film plane, and the point that is being reproduced will be rendered as small as possible.

If the cone of light is generally narrow, then the difference in the diameters of the point and the circles in front of and behind the tip is also small. In that case the transition from sharpness to unsharpness is smooth. (#3)

Most of the newer lenses are corrected in such a way that they are capable of reproducing the finest structures and details of the object.
That also means that the tips of the light cones have to be very small and that they have to subtend a larger angle (see #2). The circle of confusion will be relatively larger.
As a result these lenses will provide a visually faster transition from
sharpness to unsharpness. This might be helpful in composing the picture at full aperture, because "important" portions of the picture will stand out distinctly from the background. But the "circles of confusion" (and thus e.g. blurred highlights) will often appear somewhat more disturbing.
Didn't we talk about bokeh, recently? Wink

What do you think?

Orio · Expire: 2012-12-04

I'll leave this technical stuff to Veijo, I'm too dumb to comment on this Smile

patrickh · Expire: 2011-11-18

With digital this is further complicated by the effects of the angle of the light on the sensor...