Here's a brief look at the Sony DT 18-55mm F/3.5-5.6 SAM zoom
lens. Scroll down for the review.
Lens
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SAL-1855 Sony DT 18-55mm F/3.5-5.6 zoom lens
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Box contents
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Front and rear caps, and users manual.
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Cost
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Build quality
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OK to Good
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Additional information
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Second generation basic "DT" kit lens with "smooth auto-focus motor" or SAM.
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Specifications below
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Optical configuration
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8 elements in 7 groups
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Angle of view
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76°-29°
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Aperture
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7 blades, circular
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Full frame and APS-C
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APS-C, 35mm equivalent, 27-82.5mm. Will give full coverage on full frame cameras between 22-55mm, but APS-C size
capt. will auto crop your images using the A900. Hopefully, this will change in the future.
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Depth of field and focus scales?
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Nothing
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Minimum focus, image plane to subject
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9.85" (250mm)
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Minimum focus, end of lens barrel to subject
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4.0" (102mm)
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Hard stop at infinity focus?
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No
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Length changes when focusing?
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Yes
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Focus ring turns in AF?
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Yes, extension barrel itself
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Filter size
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55mm
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Filter ring rotates?
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Yes, extension barrel itself
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Distance encoder?
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Yes
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Max magnification
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0.34x
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Min. F/stop
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F/22-36
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Sony teleconverter compatible?
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No
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Length changes when zooming?
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Yes
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Dimensions W x L (my measurements)
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2.72" x 2.68" 69mm x 68mm add 2mm for AM/MF button on width measurement
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Maximum extended length (my measurements)
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3.46" (88mm) longest at 18mm.
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Weight bare (my scale)
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7.4oz (210g) 8.1oz (230g) with caps
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Requisite product shots.

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New Sony basic "DT" kit lens, 18-55mm F/3.5-5.6 SAM |

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New box design, no hood included. |

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Front element |

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Rear shot, plastic mount |

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New, and old kit lenses. full zoom and focus extention. |

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New and old |

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Sony X-ray view and MTF chart |
The Sony A700 was used for this review. To get a better idea about my review methods and terminology, go here. This is the newest basic "kit" wide to telephoto zoom lens available for your Sony
APS-C sensor camera, and isn't designed to be used on full frame/film cameras, but will work using APS-C size capt. on Sony
full frame cameras. The Sony DT 18-55mm F/3.5-5.6 SAM replaces the Minolta designed DT 18-70mm F/3.5-5.6 Sony has been
using since 2006. The new Sony lens has an almost satin/flat black finish, the same as the 70-300mm G SSM. It
has a ribbed rubber zoom ring, and a rather short rubber focus ring. Quality seem good, with a nice fit and finish,
but the end of the lens barrel at full extension is a little wobbly, it doesn't effect the picture though. It has a
plastic mount. Note; Sony is not including a hood with this new kit lens, which is no big deal as the one they offer
as an accessory (same as old 18-70mm hood) for $18 doesn't do any good, so don't buy it. Odd notes; the new DT 18-55mm
SAM is made in Japan, the DT 18-70mm was built in China. Sony introduces a new look for their lens boxes, see above.
Zoom control is smooth and even, the barrel runs in and out at different lengths like most cheap
kit lenses, and is fully drawn-in at 35mm. It extends out a maximum of 3/4" (20mm) at 18mm. The focal length
numbers are checked at; 18mm, 24mm, 28mm, 35mm, and 55mm. The EXIF data is off at the marked 28mm, reading 26mm, and
at 24mm, reading 22mm, but that's no big deal, other readings match up fine. This
lens is the first using Sony's new SAM or "smooth autofocus motor," which is a really cheap version of the very
good SSM or Super Sonic Wave Motor. Unfortunately, it isn't very smooth, and has the same amount of noise (or more)
as the old screw drive system, oh well. It doesn't seem to focus more accurately or faster than the lens it replaces.
With good light, focusing is fast and mostly accurate, especially with the lens stopped down. Low light focusing is
a hit or miss affair with the A700, (the A900 is much better) which uses a AF illuminator, not the flash. Models that
use the flash for low light focusing may be quicker and more accurate. See the conclusion for more information about
my thoughts on the new SAM. The filter ring turns when focusing so watch your grads and polarizers, though it doesn't
turn while zooming, that's the same design as the old lens. These kit lenses aren't really made for manual focusing.
It takes about 1/5 turn from close focus to infinity, which is not as short (1/8 turn) as the 18-70mm. The closest focusing
distance from lens barrel to subject is 4" or 102mm. Additionally, you can't use DMF, or "direct
manual focus mode" with this lens, you must use the switch on the lens itself. There is no instant auto-override
as with SSM. This is annoying to me, but again, oh well. If you press your AM/MF thumb switch on the A700,
A900, it just switches off the AF, you can still turn the focus ring, but it doesn't de-couple, so you may damage the
gears inside. It tells you about this in the owner's manual.
Aperture/focal length guide for the Sony DT 18-55mm F/3.5-5.6
SAM. This lens has overlapping numbers, for instance; you can get F/3.5 or F/4 at 20mm, depending on
tiny movements of the zoom ring, this is quite common. Look below for guide. Also, this lens miss-reads the marked
28mm length (reads 26mm) and 24mm, (reads 22mm) in the EXIF data, not a big deal, it's only off a hair. The
new Sony DT 18-55mm keeps the aperture wider as you zoom out. You're still at F/4.5 at 35mm, with the old Sony DT 18-70mm,
you're at F/5.6 at 35mm. Sony 18-55mm F/3.5-5.6 SAM below
Maximum aperture
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F/3.5
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F/4
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F/4.5
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F/5
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F/5.6
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Range
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18mm-20mm
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20mm-26mm
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26mm-35mm
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35mm - 40mm
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40mm - 55mm
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Sony 18-70mm F/3.5-5.6 below
Maximum aperture
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F/3.5
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F/4
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F/4.5
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F/5
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F/5.6
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Range
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18mm
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20mm-22mm
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24mm-28mm
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28mm - 30mm
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35mm - 70mm
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Flare and ghosting. Extremely good control here and one of the best in the Sony lineup.
The new and old lenses perform about the same at controlling ghosting, veiling glare and flare. There are some small
green blobs or arcs depending on aperture, angle from light source and zoom length. See samples below.
This
lens is multi-coated and has the regular green/magenta look, same as the old lens. Filter
size. 55mm. This size is the most popular used on Sony lenses, others using this size are: 18-70mm kit
lens, 55-200mm, 50mm F/2.8 macro, 100mm F/2.8 macro, 35mmF/1.4, 50mm F/1.4 and the 75-300mm. Filter
use. There is a tiny amount of additional vignetting at 18mm using a regular filter. Coma.
No issues, even at 18mm, F/3.5. Marginally better than the 18-70mm lens. See crops below. Color.
Looks slightly green compared to the Sony 18-70mm kit lens. Close-up type filters.
Works ok, there's not much size advantage in using one, but you shouldn't need it with the great close-focus ability of this
lens, +4 tested.
Lateral color fringing. Way above average,
and much better control than the 18-70mm kit lens. See small comparison sample crops below. Sony
18-55mm F/3.5-5.6 SAM distortion below

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Moderate to strong barrel distortion. 18mm |

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Light to moderate pincushion distortion at 55mm. |
Sony 18-70mm F/3.5-5.6 below

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Moderate to strong barrel distortion. 18mm |

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Light to moderate pincushion distortion at 70mm. |
Barrel and pincushion distortion. The distortion at 18mm is moderate to strong. It
disappears rapidly, and by 35mm it's flat. From then on pincushion starts, and results in light to moderate distortion
at 55mm. Nearly identical performance as the 18-70mm. See pictures above.
Lens Bokeh. The Sony DT 18-55mm F/3.5-5.6 SAM has a harsh background blur, especially towards
the long end, similar to other wide zoom DT lenses, except the CZ 16-80mm. See sample crops below.
light fall-off, directly below. Very mild at 18mm and F/3.5, stopping down helps out, but
there isn't a problem, even wide open. At the long end there's no problem. Very good control here for a kit lens,
and marginally better than the Sony DT 18-70mm old kit lens.
18mm @ F/3.5
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18mm @ F/5.6
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55mm @ F/5.6
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55mm @ F/8
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Examples of color fringing and ghosting below.
18-55mm @ 18mm, F/5.6 color fringing crop from far left side
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18-70mm @ 18mm, F/5.6 color fringing crop from far left side
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18mm @ F/5.6 green blob
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18mm @ F/5.6 green arc
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The top cropped images compare color fringing at 18mm, F/5.6 between the two DT kit lenses, taken from
the left border of the image. The newer 18-55mm is obviously the best at controlling lateral CA, this type doesn't go
away as you stop down. You can also see the difference in image color in these crops, the 18-55mm being more green than
the magenta biased 18-70mm. Also notice the new lens is sharper at the image periphery. The two
lower shots show ghosting control, which is very good, and about the same as the old DT 18-70mm. The 18mm sun-in-shot
image shows a green blob at the middle one o'clock position. The 55mm end with the sun just out of the shot shows some
slight veiling glare, with a faint green arc at the top right. This is the worst of it, and is still far better than
the majority of Minolta/Sony lenses. Random shots below.
18mm @ F/3.5 bokeh
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18mm @ F/5.6 bokeh
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55mm @ F/5.6 bokeh
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55mm @ F/8 bokeh
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18mm @ F/3.5 coma
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18mm @ F/5.6 no coma
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Bokeh looks just fair at the wide end, but harsh at the long end, this performance
is about average for less-expensive "kit type" lenses. The last row shows the
lack of coma, again, it's marginally better than the Sony 18-70mm. Very good contol here. Corner softness. 18mm corners below.
18mm @ F/3.5
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18mm @ F/5.6
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18mm @ F/8
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18mm center at F/3.5
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Things look darn good here, even at F/3.5. There is no real difference in corner sharpness at wide
angle by stopping down the aperture, even when looking at 100% crops. I threw in a center crop so you can see how sharp
the corners are, comparatively speaking. The corner crops look different from the center shot because that's the way
a wide angle lens renders images at the corners. 55mm corners
55mm @ F/5.6
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55mm @ F/8
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55mm @ F/11
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55mm center at F/8
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The 55mm corner crops respond slightly to stopping down, though the center crop looks sharper. F/16 was about
the same as F/11.
Center samples next. 18mm
centers
18mm @ F/3.5
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18mm @ F/5.6
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No problems here at wide angle and F/3.5. This lens controls veiling haze better than the 18-70mm
from F/3.5-4.5, 18mm. 55mm centers.
55mm @ F/5.6
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55mm @ F/8
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There's a slight lack of contrast at 55mm, F/5.6, one stop down produces the sharpest image, F/11 is the same as
F/8.
Check out the close focus shot.
Below, check out the sample (718kb) and click to see a 100%
cropped portion of the full image. The sample shot was taken with the Sony A700 12.2MP camera. The subject is a standard US stamp, 1"x 3/4" or 25.4mm x 19mm. Also, note the macro
shot was taken as close to the subject as focusing allowed; In this case, 4" or 102mm, measured from the front of the
lens barrel to the subject. The new Sony 18-55mm SAM lens has a large reproduction size at 0.34x. It did
a good job at F/5.6, but the left side by the "2006" showed slightly soft, F/8 is the sharpest in the center with
improved corners, F/11 turned in the sharpest all-around average. This lens turned in the best close-focus stamp shot
out of all the lenses I've tested so far, except for real (1:1) macro lenses!

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100% crop, F/8, click me |
Bonus section with comparisons to the Sony 18-70mm F/3.5-5.6 kit
lens. 18mm centers.
Sony 18-70mm @ 18mm @ F/3.5
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Sony 18-55mm @ 18mm F/3.5
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As I said above, the 18-70mm has a bit less contrast than the 18-55mm when used at wide angle, and F/3.5.
Shots were taken at infinity, everything should be sharp, including the wall at the bottom of the crop. 18mm
corners below.
Sony 18-70mm @ 18mm @ F/3.5
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Sony 18-55mm @ 18mm F/3.5
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The corners are sharper between F/3.5-5.6 on the new 18-55mm at wide angle, and color fringing is controlled
better, making the difference more noticeable. 55mm centers.
Sony 18-70mm @ 55mm @ F/5.6
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Sony 18-55mm @ 55mm F/5.6
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The 55mm centers are noticeably sharper at F/5.6 on the newer 18-55mm. 55mm
corners.
Sony 18-70mm @ 55mm @ F/8
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Sony 18-55mm @ 55mm F/8
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The 55mm corners from the old 18-70mm look slightly better, a surprise, but not noticeable unless viewed
side-by-side. 70mm centers, upsampled for 18-55mm.
Sony 18-70mm @ 70mm @ F/11
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Sony 18-55mm @ 55mm, F/8 upsampled
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Here's another surprise. The 18-55mm is sharper in the center at 55mm than the 18-70mm is when
set to 70mm. I upsized the 55mm image from the 18-55mm to match that of the 70mm image from the 18-70mm. So much
for supposedly "losing" 15mm of focal length on the long end with the new lens. This would only show up if
you had your image enlarged to poster size, so don't get too excited. Note; the 18-70mm at 70mm was sharpest at F/11,
the 18-55mm, at F/8, 55mm, that's why I used those apertures for the crops above. All images above were taken at infinity
focus, so everything in the crop should be sharp Conclusion. The
Sony DT 18-55mm F/3.5-5.6 zoom is the basic, least expensive "kit lens" offered by Sony, and replaces the Sony 18-70mm F/3.5-5.6, which is a Minolta
designed lens. It'll cost you between $50-$100 extra in the kit, or $199 by itself. Build quality is rather cheap,
but totally adequate for the intended purpose, an that's for use by people just getting started in DSLR photography and don't
need focus scales, or non-rotating focus rings etc. Optically, this lens is better in nearly every
way than its predecessor. Feel free to use the lens at any aperture, and zoom length and don't worry about sharpness
or color fringing. If you shoot at or near 55mm, one stop down will produce the sharpest shots. Macro shots are
much larger and sharper than on the old lens. Optically, Sony really did a good job re-designing their new "DT"
kit lens. I think it will easily match up to the Canon and Nikon in optical performance. Do you wonder why I keep
mentioning the word "optical"? Read on. Auto-focusing performance is about
the same as the old 18-70mm F/3.5-5.6. That means the highly touted "SAM" or "smooth autofocus motor"
is no better than the screw drive system in the old lens. Here's my opinion; the "SAM" was designed solely
by Sony marketing people in a misguided attempt to try and keep pace with Nikon and Canon silent-wave and ultrasonic focusing
systems etc. Unfortunately, the "smooth autofocus motor" is just as loud (if not louder) than the screw drive
system, and the "smooth" part is no smoother, there's just as much "hunting and "jerking" in low
light as the old lens. Focusing accuracy is about the same, using wide or spot. Bottom line; my Canon digital
rebel from 2003 has a kit lens that's much smoother, and quieter, with more accurate focusing (in low light) than the new
Sony 18-55mm F/3.5-5.6 lens. Sony decided to go cheap, and not utilize the proven, and excellent SSM focusing system.
Sony is gambling that potential customers (and current users) won't notice stuff like this. I think they may be wrong.
Hopefully a refined version is already in the works, with true SSM, plus, make the focus ring de-couple when using the thumb
AF/MF button, (or DMF) instead of having to manually switch the lens button to "MF" to disengage (de-couple) the
focus ring.
Don't fret too much folks. The lens is good, and the focusing is as good
as the old lens. Sony did a nice job optically, the SAM just needs major improvements.
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