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Sony 18-70mm f/3.5-5.6 DT SAL-1870

 
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Buy the Sony 18-70mm f/3.5-5.6 DT SAL-1870

Lab Test Results

  • Blur
  • Chromatic Aberration
  • Vignetting
  • Geometric Distortion
18-70mm $96
average price
image of Sony 18-70mm f/3.5-5.6 DT SAL-1870

Introduction
The 18-70mm ƒ/3.5-5.6 DT is the standard ''kit'' lens that ships with current Sony body / lens combinations. With an effective focal length in 35mm terms of 27mm to 105mm, the lens is versatile in wide-angle and light telephoto application. The lens is technically identical to its Konica-Minolta predecessor.

The 18-70mm ƒ/3.5-5.6 is a full-frame lens design, so it won't vignette on a Minolta film body or a full-frame Sony body. It weighs in at just over 8oz (235 grams) and takes the smaller 55mm filters. It ships with a solid circular lens hood and a carrying case, and is available for around $200.

Sharpness
The 18-70mm ƒ/3.5-5.6 offers above-average performance, never hitting a truly tack-sharp image, but not showing any noteworthy flaws, either. Corner softness is an issue in just about every focal length and aperture combination, but for the most part, you're looking at a difference of just 1-2 blur units, according to our blur test chart.

It's a hard one to call, but I would say the optimal point for this lens is at 50mm and ƒ/8. The image is quite sharp (1.5 blur units across the image) and at this setting you don't see the corner softness. The lens is actually quite well optimized at 18mm and ƒ/3.5, where many people will use it, quite sharp in the middle of the image and only slightly softer in the corners; this softness increases as you increase the focal length by zooming in.

Image sharpness degrades due to diffraction limiting as the aperture approaches the smaller end at ƒ/16 and above. As far as sharpness is concerned, there isn't a compelling reason to go above ƒ/16 - images are quite soft at this setting.

Chromatic Aberration
Chromatic aberration is quite evident at all focal length settings lower than 50mm, predominantly in the corners of the image. At smaller apertures chromatic aberration increases, so if you need to shoot wide, try and use a wider aperture to minimize this effect. At 50mm and above chromatic aberration is not noticeable except with some intense pixel-peeping.

Shading (''Vignetting'')
As is the case with most wide-angle zooms, there is some significant light fall-off in the corners when shooting wide-angle and wide-open (18mm, ƒ/3.5) - over a half-stop difference. Zooming in to 24mm decreases this to a quarter-stop, and at all other settings you're looking at less than that.

Distortion
No surprises with distortion here - as is typical for wide-angle lenses, set below 50mm there is significant barrel (''bloat'') distortion, seen at its most obvious at 18mm, where you're looking at almost a full 1% geometric distortion in the corners, and half a percent throughout the rest of the image. Happily this distortion decreases to near-zero as you approach 50mm, and pincushion distortion isn't a significant factor after that through to 70mm.

Autofocus Operation
The focusing operation of Sony 18-70mm ƒ/3.5-5.6 is conducted mechanically. The autofocus isn't particularly fast or quiet, talking probably around one second for the entire range. It's not an internal focusing lens, so there is some forwards-backwards travel as the lens focuses, but more importantly, the assembly rotates as it focuses, meaning any filters attached are also going to rotate as they focus. Not a huge issue, it just means that while using a polarizing or graduated filter you'll want to make sure you're focused before you align your filter to your preference.

Macro
The lens isn't a dedicated macro lens, but it focuses fairly close (1' 3'', 38cm) from the subject. The lens provides a magnification of 0.25x.

Build Quality and Handling
The lens is very well constructed, with a rugged plastic mechanism. Being a budget lens there aren't any frills such as a distance scale or aperture ring. The lens extends during zooming, almost half again its length. The focus ring travels about 1/4 of the diameter: not great for accurate manually focus, and the focus ring is almost an afterthought, with no real depth to grab on to. You can hear the gears whirring as you turn the focus manually. Being gear-coupled, manual focus can only happen when the camera is in MF mode.

Alternatives

Sony 16-80mm ƒ/3.5-4.5 DT Carl Zeiss ~$700
While a fair bit cheaper, this lens is a much higher quality lens than the 18-70mm, so you are getting what you pay for - somewhat sharper (though we detected significant issues with corner sharpness at certain settings) and a much higher build quality. The 16-80mm does have some issues with vigetting at wide angle (at 16mm, what lens doesn't) but distortion and resistance to chromatic aberration are better addressed.

Konica Minolta 18-70mm ƒ/3.5-5.6 D AF DT ~$90
This lens is technically the same as the Sony 18-70mm ƒ/3.5-5.6, but it was discontinued when Sony bought out Konica-Minolta. If you can find one used, it should give the same performance as the Sony but for a lot cheaper.

Sigma 17-70mm ƒ/2.8-4.5 DC Macro ~$350
A bit wider maximum aperture, slightly wider-angle and with the added perk of an integrated macro mode, for a few extra dollars you get a sharper lens with vastly better resistance to chromatic aberration, comparable distortion but a bit worse vignetting.

Conclusion
The Sony 18-70mm ƒ/3.5-5.6 is a capable kit lens, producing consistently above-average sharp images. It has some weak points - chromatic aberration below 50mm, and we're not big fans of lenses whose front filters turn while focusing or zooming. You shouldn't feel bad if you got this lens as part of the kit - you need to start with something, and while it's not the sharpest lens in the box it's not that bad, either. However, at these price points, if you're shopping for something in this range you might find a bit better performance for the money with the Sigma 17-70mm ƒ/2.8-4.5. Or, if you want to stay loyal to the Sony brand, invest a bit more in the Sony 16-80mm ƒ/3.5-4.5. Finally, if you're really stretched for cash and you can find one, the Konica-Minolta 18-70mm ƒ/3.5-5.6 is technically the same lens.

Sample Photos

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.

Sony 18-70mm f/3.5-5.6 DT SAL-1870 User Reviews

6.1/10 average of 8 reviews Build Quality 5.5/10 Image Quality 6.1/10
  • 5 out of 10 points and not recommended by (52 reviews)
    good range for a lenskit, cheap
    cheap build, soft wide open

    I got this lens along with my A200 body. I was happy for the price, I thought it would make a great value for that range (18-70). In real use, this lens produces soft images, quite unusable (for me) until I stepped down to f/8. Then it would require lots of light.
    I prefer the "shorter" 18-55 than this one, just because the IQ issue. This lens is a no-no!

    reviewed October 13th, 2012 (purchased for $75)
  • 4 out of 10 points and not recommended by (3 reviews)
    Light weight
    Poor image quality

    Having had decades of experience with film SLRs, this lens came with my first dSLR (Sony A350).

    The camera is fine, but the lens - what a disappointment. Might as well have stuck with a digital compact.

    I've since replaced it with a Tamron 18-200. Not perfect by any means, but a considerable improvement on this Sony lens.

    reviewed June 24th, 2009
  • 7 out of 10 points and recommended by (2 reviews)
    Range
    Build Quality

    This was the first lens that i ever used on the pro side there is the obvious nicer focal length compared
    to the other kit lenses and although it doesn't seem much a 70mm lens has the field of view of 105 mm
    on a APSC sensor and that can really help in many situations. it has a "macro" reproduction rate of 1:4
    which is good for flowers and large bugs but it's not a macro lens by far if you want better macro
    capabilities get the sigma 17-70 f2.8-f4.5 which has a max. magnification of 1:2.3 that being very
    impressive for a standard zoom lens.
    Sharpness:
    quite good here nothing to really complain if you don't plan to make huge prints this is a good
    lens for you i would say A3 would be the limit for the prints. I usually shoot f5.6 and f8 those seem
    to be the sharpest but f11 is perfectly usable to
    Build Quality:
    the lens body is made out of plastic something common for kit lenses and it feels a bit loose
    attached to the camera i feel "safer" with my tamron attached. The focus ring is a bit small though but
    with the hood attached it won't be a problem even for those with big hands but on the up side the zoom ring has a very smooth movement.
    Focusing Speed:
    although it doesn't use a internal micro motor is still good but a bit noisy,
    that can be sometimes disturbing especially when trying to shoot people who don't expect you to take pictures of them suddenly they become aware and the shot gets ruined :)
    Chromatic aberrations:
    i rarely saw chromatic aberrations in my shots viewed at like 35% but at 100% they become more
    obvious anyway it handles CA a lot better than my tamron 70-300(at 300mm)
    after checking some reviews this lens apparently produces alot of CA i must have gotten lucky with the
    sample...
    Flare:
    this can be a problem sometimes do to the little hood they supplied you can try to block the sun light
    with your hand
    Distortions:
    there are some barrel distortions at 18mm but not really noticeable in real life shots only
    maybe if you shoot a lot of straight lines :P
    Vignetting:
    i have only noticed a bit of vignetting at 18mm f3.5 but shooting like that in the day-time
    when the sun is way up in the sky is not really a option
    Bokeh:
    i have mix feelings about the bokeh because it has 7 circular blades it produces quite pleasing bokeh
    but sometimes when the background has strong lights the bokeh seems pretty harsh and it can be very
    distracting
    All in all it's a pretty decent lens which can take great shots. If you don't really need a constant f2.8
    aperture or if you don't make huge prints i don't really see the reason for upgrading to the tamron 17-50mm
    f2.8 for example.

    some sample shots here ---> http://www.flickr.com/search/?w=29429803%40N06&q=18-70+DT&m=text

    reviewed May 20th, 2009 (purchased for $100)
  • 6 out of 10 points and recommended by (1 reviews)
    compact, light, decent performance
    not exceptional at anything

    Contrary to what was stated in the review notes section, this was NOT designed for a full frame camera, hence it won't work perfectly with the A900. It vignettes badly at 18mm and doesn't clear up until 24mm or so, at least on my Maxxum 7.

    The lens performs as expected for this type. It's a little sharper than I expected, stopping down helps. It covers a nice range, though I also own a Sigma 24-60 f/2.8 which stays on my camera most of the time.

    For the average person, this lens is great and even for an artist, it could be made to work.

    reviewed July 23rd, 2008 (purchased for $63)
  • 6 out of 10 points and recommended by (2 reviews)
    Good focal range, good value
    Solid results if you stay within it's capability

    I've had this lense since January '08 and have been getting good results. It really helps too stop down from wide open and never go past f/16.
    Review states the lense is designed for full frame, but it does not cover full frame on my 35mm bodies near 18mm. No biggie, I don't shoot film...
    I have Minolta 28-85 and 70-210 lenses. Recently shooting at 210mm, F/5.6, and handheld, the 70-210 blew away the IQ of the 18-70 DT (making me realize this lense is not as good as I thought), so I've updated my post. (downgraded my rating of this lense)
    Overall a solid lense for the price, still think it's a good place to start, but now I'm going to upgrade :)

    reviewed June 21st, 2008 (purchased for $90)
  • 10 out of 10 points and recommended by (11 reviews)
    Very light, sharp, cheap
    Feels cheap

    This lens is very under rated, that's why I gave it a 10 for all. After all, you need to compare the price against the quality and I don't think a 16-80 CZ, which costs 5 times more, will give a 5 x better picture.
    I can compare it with the 18-70, 18-135 of Nikon with the D300 and the Canon 17-85 IS with the 40D. In no way I feel this lens is any worse or the others better. Sharpness is good and the colors are great with the A350. Possibly the 16-80 has even more sharpness, but then again, it's not an honest comparison.

    reviewed May 11th, 2008 (purchased for $150)
  • 5 out of 10 points and not recommended by (3 reviews)
    cheap
    build quality is not what you expect from sony.

    this lens comes as kit part with Sony A100 camera, or you can buy it for $200 ( msrp) ,
    good lens for the price , but if you have extra $ get somthing beter.
    comes with lens hood and caps.

    reviewed December 2nd, 2006
  • 6 out of 10 points and recommended by (2 reviews)
    Cheap, sharp across the zoom range
    slow from around 40mm, very cheap feeling

    I have used this one and the Nikon 18-70 f.3.5-4.5 this in my opnion is just as sharp if not just a little sharper however it is slow compared to the nikon and the nikon focuses alot faster.

    All be said a very good kit lens and definately a must include if you don't have any other lens (i.e. don't buy body only)

    reviewed November 16th, 2006