Your DSLR can take outstanding photos on its own in auto mode, so why would you want to switch to manual? This video tutorial will explain the reasons why as a photographer you might want full manual...
The Sony 75-300mm f/4.5-5.6 appears to be similar, if not
identical, to the earlier Konica-Minolta 75-300mm f/4.5-5.6 lens which
was in production before Sony took over the Konica-Minolta line of
cameras and lenses.
The Sony 75-300mm f/4.5-5.6 has "twist-to-zoom" operation using a wide
ring in the center of the lens. Manual focus is via a narrower ring at
the front of the lens (AF/Manual switching is done via a switch on the
camera body, not on the lens).
Auto focus operation is quiet and reasonably fast, but not of
course as quiet or as fast as a lens using the Sony SSM motor
system. I did notice some focus hunting with the lens on a
Sony Alpha A700 (review), when used at 300mm in
low light, but under normal daylight conditions focus was pretty
positive and the lens did not hunt.
The lens drops to an f/5.6 maximum aperture at a fairly short focal
length setting (around 125mm).
I only had the opportunity to test the 75-300/4.5-5.6 lens on a Sony
Alpha A700, which is an APS sensor DSLR. The lens has full frame coverage
(though currently Sony doesn't have a full frame DSLR). Optical performance
would be expected to be worse at the corners of a full size 35mm frame than
at the edges and corners of an APS-C sized sensor.
Test charts are a pretty severe test of optical performance and as you can see
from the 100% crops above, the 75-300/4.5-5.6 shows some problems when used wide
open, especially in the corners at 300mm and to a lesser extent at 75mm. The best
performance is seen around 135mm (f5.6).
Stopping down to f/8 improves things a bit as can be seen from the set of crops
above. Again performance is best at 135mm.
Finally, here's a real world example captured at 300mm and
f/5.6. On the left (above) is the full image and on the right (above)
is a 100% crop. This image is taken straight from the camera using all default
settings. It can be sharpened up by some post-exposure processing in
an image editor such as Photoshop. On the left is the same image shown
above, but this time sharpened somewhat. As you can see it looks quite
a bit sharper and isn't showing too many undesirable sharpening
artifacts. Remember that a 100% crop from the A700 when displayed on a
17" monitor at 1280x1024 screen resolution is equivalent to looking at
a crop from a print that's at least 24"x36", so it's a significant
The Sony 70-300 f/4-5.6 G SSM, (compare prices), is Sony's other lens in this
range, but it's built to a higher standard using ED elements to
maximize image quality and a Sony SSM (Super Sonic wave Motor) for
fast and silent focusing. The downside of the increased quality is
cost, and the 70-300 G-series lens costs about 3.5x as much as the
The Konica-Minolta 75-300mm f4.5-5.6 D appears to be essentially
the same lens as the Sony. It's no longer in production, but if you
can find one it may well be significantly cheaper than the current
Sony lens. The last street price on the lens was around $140
The Sony 75-300/4.5-5.6 is a typical inexpensive telephoto
zoom. Performance peaks around 135mm with sharp images both in the
center of the frame and at the corners of the APS-C frame. As the lens
is zoomed in or out the image softens somewhat, especially in the
corners, and chromatic aberration becomes more visible at the edges of
the frame. If you don't mind 3rd party lenses, the offerings from Sigma
and Tamron would seem to be well worth considering based on their
greater macro magnification, use of LD glass and lower price.
Where to Buy
You can get this lens from amazon.com. It's normally in
stock and overnight shipping is available.
Sony 75-300/4.5-5.6 Specifications
75-300mm (112.5-450mm full frame equivalent when used on
Sony Alpha A700,
set at 230mm, 1/640s, f/5.6, ISO 200, multi-segment metering. Even
though the edges of the images may get a little soft with this lens at
230mm, in many situations (such as this one), the center of the image
is much more important than the edges (which will be out of focus
Sony 75-300mm f/4.5-5.6, set at 180mm, f/5.6,
1/40s, ISO 400, multi-segment metering, manual exposure mode. Although
this decorative light fixture was photographed against a luminescent
window, the A700 did a great job with the colors, sharpness. I used
the AE Lock button to focus on the colored object before recomposing
Sony Alpha A700, set at
75mm, 1/250s, f/5.6, ISO 400, multi-segment metering. At 75mm the
image sharpness is quite good across the frame.
Sony Alpha A700, set at
75mm, 1/100s, f/5.6, ISO 400, multi-segment metering. Though the sky
is bright and the foreground dull, the A700 has just avoided
overexposing the sky (average level around 252, where 255 is