[Leica] My perspective on "Tack Sharpness"

[Jim Brick <jim@brick.org>]

Tack sharpness is in the eye of the beholder. Many times, with a shallow
depth of field, and the edge of something critically sharp, it looks
*sharper* because it's the only thing sharp. There also must be contrast
between the sharp and the unsharp. It also depends upon the final image. is
it a 4x6 or a 16x20, or a 10x loupe and light box. Everything is relative.

For the first 30 years of my life I shot (rifle) competitively. I learned
breathing, squeezing between heartbeats, etc. When hand holding a camera
(very rarely with my R Leicas, but always with my M2) my shooting
experience pays off. However, there is a limit. R cameras have a mirror
that simply causes vibration. It's a fact of motion physics. So there is a
limit to how slow you can realistically hold an R camera. The M camera has
very little built-in vibration so a skilled photographer can do quite well.

But... it's still relative. Relative to what you or your client will
accept. When I print a 16x20 or 20x24, I want it to *jump* off of the
paper. But of course, the subject matter plays an important part of
sharpness. Nature, close-ups, leaves, flowers, etc should be crispy sharp.
Street scenes, night scenes, mood scenes, vista landscapes, etc, can be
less sharp and still look visually perfect.

So I do not believe you can define what is critical sharpness, broad
spectrum, for everybody. Everyone photographs different subjects. Everybody
uses the results differently. From family albums to Gallery hangings. Who
can hand hold a camera down to 1/who-cares(th) of a second is not a
realistic endeavor. Who cares. In the final analysis, you only have to
satisfy yourself. So if you say that you can hand hold your camera
consistantly at 1 sec exposure, that tells us a lot about what your
sharpness acceptance level is.

Jim