To help in the understanding of all the lenses Pentax has released since the late 60s,
I've put together this listing of the various lens series Pentax has released.
For even more information, here are two classic sites. The first has a lot of good
information on the K mount Pentax cameras, lenses and accessories. The second is
the classic lens review site for many of the pre-digital lenses.
http://www.bdimitrov.de/kmp/ http://stans-photography.info/
TAKUMAR:
Pentax used the name Takumar when the lens mount was a 42mm screw mount.
In 1971 Pentax came out with its Super Multi Coating, (SMC). A seven layer
coating which reduced internal reflections and UV light, resulting in improved
contrast, color saturation, and flare resistance. Super-Takumar (pre-1971)
lenses had only up to two coating layers and therefore are more prone to flair.
SMC Takumar's while optically identical have the seven layer coating.
They had a manual/automatic diaphragm and manual focus.
K Lenses:
In 1975 Pentax changed to the current quarter twist K-mount and their lenses K.
These were mostly optically identical to the Takumars but with a new mount.
They had an automatic diaphragm and manual focus. Many had rubber focus rings.
M Series:
Shortly afterwards (70s) the market changed so Pentax came out with M series
camera bodies, and a new lens series named M. Both the camera bodies and the
lenses were noted for their small size. (Influence of Olympus). They were
mostly of new optical designs. They had an automatic diaphragm and manual focus.
A Series:
In 1983 Pentax came out with a fully automatic program mode camera.
(camera can set both shutter speed and aperture). This required that
the lens be able to transmit information through electrical contacts
back and forth to the camera and allow for the camera to fully select
the lens aperture. These lenses were called A. It features an automatic
setting on the aperture ring. Manual focus.
A* Series:
During the A period Pentax also introduced 9 A* lenses which used
top of the line optics. Many of these lenses were and still are considered
some of the best made. The star series was carried on for 3 F* and 10 FA* lenses.
(The first star lens was the M*300mm f4 made starting in Apr. 1981--
The only * in the M series).
F Series:
In 1987 Pentax came out with an autofocus (AF) camera (SF series)
which required a new lens. They were called F.
FA Series:
In 1991 Pentax introduced the PZ series of cameras and also a new lens series
which it called FA. These lenses were basically F series lenses with a microchip
giving the camera MTF data for that particular lens and power zoom.
FA Limited Series:
In 1997 Pentax came out with its first Limited lens the FA Limited 43mm f1.9.
At the time lenses were being made from plastic, Pentax choose to come out
with a series of lenses of unique focal lengths using the highest optical design
and all metal materials, manufactured to the highest quality. There are three
lenses in this series: 31, 43, & 77mm.
FA-J Series:
In 2003 as part of the release of the smaller and lighter *ist 35mm SLR camera,
Pentax released an affordable series of three all plastic construction zoom lenses
(18-35, 28-80 and 70-300) without an aperture ring and a plastic lens mount.
DA Series:
Shortly after the release of its first digital SLR, (*istD) Pentax came
out in 2004 with a series of lenses made especially for the new APS-C
digital sensor. This series is engineered exclusively for digital cameras.
That means no more aperture ring, and its effective image circle is smaller
than all previous lenses and will only cover an APS size sensor.
(35mm film is 36mm x 24mm; Pentax's APS-C is 23.5mm x 15.7mm).
It also included a "Quick Shift Focus", which is basically a clutch that
allows for manual over ride of the AF system, and new coatings to reduce
internal flare and ghost reflections needed for digital sensor.
DA Limited Series:
Similar to the FA Limited series, these three lenses, (21mm, 40mm, and 70mm)
are of the highest optical design, full metal construction and manufactured
to the highest quality. They are all "pancake" type design. The 40mm was released
in 2005 followed by the other two. A 35mm macro Limited has been announced (Feb. '07).
Expected release is late 2007. It is not a "pancake" design.
D FA Series:
In a joint project with Tokina, Pentax released two macros (50 & 100mm f2.8 )
in this series in 2006. While compatible with 35mm cameras (image circle for 36x24mm),
these lenses utilized coating, curvature, and positioning of optical elements to
virtually eliminate flare and ghosting for clear, high-quality images particularly
important to digital photography.
DA* Series:
After the release of the K10D, Pentax announced another lens series called DA*.
Released in the second half of 2007, the first three zooms are from a joint
development with Tokina. Along with being of the highest optics these lenses
are weather sealed, and so far all have SDM.
SDM is a supersonic motor mounted in the lens to facilitate auto focusing
controlled via two more electrical contacts between the camera and lens.
Up to this point, the camera has done the lens AF via a small in-camera motor
and AF coupler located in the mount.
ED (Extra-low Dispersion) glass reduces chromatic aberration.
AL (Aspherical Lenses) have a curvature that changes continuously in the direction
of the lens diameter. They are used to decrease the incidence of spherical aberration.
IF (Internal Focus) is used in lens nomenclature when the optical elements do
not leave the lens housing to achieve focus.
