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This
telephoto macro lens provides life-size reproduction and it is optimized
for digital cameras.The new multi-layer lens coating reduces
flare and ghost, which is a common problem with digital cameras. Two SLD
(special low dispersion) glass elements ensure high optical performance
for film SLR cameras as well as digital SLR cameras.
Taking
pictures of small animals and insects can be difficult, because they often
run or fly away, or can be dangerous or become aggressive if you approach
them. Therefore it is advantageous to have a greater working distance
between the camera and such subjects. Longer focal length lens can provide
this greater distance, but most long lens do not focus close enough to
provide a large image of small subjects. The tele-macro type lens solves
this problem by producing a large, high quality image, up to life-size,
while maintaining a long working distance. This can enable you to capture
on film the world of photomicrography, without disturbing the subjects.
The 180mm F3.5 EX DG MACRO lens has a very narrow field of view, and can
allow very narrow depth-of-field for selective focus and less distracting
backgrounds. This lens is most desirable for photographers who are serious
about producing high quality images both of macro subjects at life-size
reproduction, as well as normal telephotography.
The Floating Inner Focus System of the APO MACRO 180mm F3.5 EX DG HSM
provides high quality optical performance and superior handling and stability.
This system moves two lens groups within the lens, so the lens' physical
length remains unchanged. This technique also maintains good correction
for Spherical Aberration and Astigmatism and provides extremely high optical
performance from infinity to 1:1 Macro.
Macro photography requires precise focus adjustment. The HSM (Hyper Sonic
Motor) feature is ideal for this purpose as it allows quick and precise
manual focus, even in auto focus mode. Simply focus with HSM auto focus,
then while partially depressing the shutter release, turn the manual focus
ring until any desired focus adjustment is made. Then depress the shutter
release fully to take the picture. It is not necessary to switch from
AF to MF. When the shutter release is next depressed, the AF function
will resume. Of course the AF function can be disabled altogether, and
only MF used, if desired.
Macro photography can be further enhanced by the 1.4x APO EX tele-converter,
which allows the photographer to use the new SIGMA APO 180mm F3.5 MACRO
lens as a 252mm F5 lens while maintaining auto focus function from infinity
to 1.2m with Canon, Nikon and Sigma cameras. At distances closer than
1.2m the lens automatically switches to MF mode. When this lens and the
1.4x EX tele-converter are used with Minolta or Pentax cameras the lens
must be focused manually. When used with the 2x EX tele-converter, the
180mm F3.5 lens becomes a 360mm F7 lens with manual focus function only,
regardless of camera mount.
Image quality depends in part on color Aberration, which occurs due to
differences in the wavelength (color) of light, causing the different
colors to focus at different planes. SLD glass in the front optical group
helps compensate for this phenomenon, and enables the lens to deliver
images of high optical quality, having outstanding crispness and sharpness.
