Page 103 - Friedman Archives

Lenses 103

technology.
SAM and SAM II – Introduced in 2009, the Smooth Autofocus Motor
(SAM) lens is another type of lens which incorporates the focusing motor
in the lens rather than in the body. It
is less expensive (and noisier!) than
the SSM lenses described above, but
according to my tests it makes less
focusing noise in videos than a lens
which uses the in-body focusing
motor. (See my blog at
http://tinyurl.com/6ezytcx and
scroll down to “Quiet AF for video”.)
I don’t like these lenses because 1)
they’re needlessly loud, and 2) they
have a focusing switch on the side
which wreaks havoc with the
simplicity of the Focus Mode knob.
(SSM lenses have this switch too, but
its interference isn't quite so
annoying. See differences outlined
in Section 10.17.)
D – “D” stands for “Distance”; it Figure 3-24: The “screwdriver blade”
means that the lens will tell the couples the in-body focus motor with
camera body to what focusing the older autofocus lenses.
distance the lens is set. (Yes, believe
it or not, with early autofocus bodies, although the camera could tell when
the subject was in focus, the camera had no idea how far away the subject
was!) This feature was introduced in the year 2000 to help make flash
exposures more accurate when shooting with highly reflective
backgrounds, and is essential for the ADI flash mode (explained in Chapter
5) to work properly. All new Sony and Zeiss lenses will have the “D”
feature.
AF – This just means “Autofocus”, and is used to distinguish it from
Minolta’s older “MC”, “MD”, or “MF” manual-focus lens mounts. Since
the lens mount was changed completely when Autofocus was introduced
(in 1985), a manual-focus lens cannot be used on an autofocus body.