The Sony DT 16-105mm 1:3.5-5.6 was announced in September 2007, as a premium kit lens to accompany the Alpha 700 DSLR. Sony has thankfully (and uncharacteristically) managed to avoid the over-proliferation of letters which afflict lens names from other manufacturers, with just the ‘DT’ badge (for Digital Technology) indicating that the design is optimised for cameras with APS-C imagers. Sony’s information also reveals that the lens incorporates one ED (Extra-low Dispersion) glass element and two glass aspherical elements, promising minimised colour aberration and excellent contrast across the zoom range, plus a circular aperture for pleasing background blur.
However the 16-105mm is more than just an upmarket kit lens, and offers arguably the most interesting focal length range of any DSLR lens currently available, ranging from a 24mm-equivalent wideangle to a 160mm-equivalent telephoto; indeed for many photographers the wider-than-average angle of view will be more useful than the extended telephoto ranges found on the current crop of superzooms. This follows in something of a tradition for this lens’s Minolta predecessors, which included a 24-105mm standard zoom for 35mm SLRs when other brands only offered 28-105mm lenses. Adding to the attraction is the fact that this is achieved within a compact, lightweight package, ideal for travel or just general purpose ‘walkaround’ use. So does this new kid on the block have the substance to spearhead Sony’s intended drive towards DSLR world domination? Let’s find out.
- 24-157.5mm equivalent focal length range
- F3.5-5.6 maximum aperture
- Alpha mount for Sony and Konica Minolta APS-C DSLRS
Angle of view
The pictures below illustrate the focal length range from wide to telephoto:
|16mm (24mm equivalent)||105mm (157.5mm equivalent)|
Sony DT 16-105mm 1:3.5-5.6 specifications
|Street price|| US: $550
|Date introduced||September 2007|
|Maximum format size||APS-C|
|35mm equivalent focal length (APS-C)||24-158mm|
|Diagonal Angle of view (APS-C)||83°- 15°|
|Lens Construction||• 15 elements / 11 groups
• 1 ED glass element
• 2 aspherical elements
|Number of diaphragm blades||7|
|Maximum magnification||0.23x at 105mm|
|AF motor type||‘Screw drive’ from camera body|
|Filter thread||• 62mm
• Does not rotate on focus
|Supplied accessories||• Front and rear caps
• Petal-type lens hood ALC-SH105
|Weight||470 g (16.6 oz)|
|Dimensions||72mm diameter x 83mm length
(2.8 x 3.3 in)
|Lens Mount||Sony Alpha/Minolta MA|
|Other||Distance encoder for ADI flash metering|
* Supplied accessories may differ in each country or area
The 16-105mm features an attractively minimalist design which is devoid of any cosmetic fripperies. It feels solidly built, with a metal lens mount and barrel constructed from quality plastics; an impression no doubt reinforced by the fact that it is something of a heavyweight for such a small package. It may not be as well made as the professional-grade 24-70mm F2.8 zoom, but it feels like it should stand up to fairly intensive use.
However the utilitarian approach is not without its pitfalls. The zoom and focus rings use the same shallow ribbed grip rubber and are of similar diameter and width, so are impossible to distinguish by touch alone. And disappointingly for a premium lens, the focus ring is extremely stiff and has a very short travel, which makes manual focusing something of a trial. The zoom action is also slightly uneven in feel.
On the camera
The lens is perfectly balanced on the Alpha 700 we used for studio testing; the zoom and focus rings both fall within easy reach of the left hand thumb and forefinger. Thanks to its compact design, it also works well on the smaller entry-level bodies such as the Alpha 350 (which we also used for real-world shooting); here the only slight negative is a risk of flash shadowing at wideangle.
Autofocus is driven by a screw-drive system from the camera body, so AF speed, noise and accuracy is fundamentally dependant on the camera used. On our Alpha 700 test body, we found focusing to be generally fast and accurate under most conditions, although with a distinct tendency to hunt for focus in low light at the telephoto end (which is not surprising given its F5.6 maximum aperture).
Lens body elements
|The lens uses Sony’s Alpha mount, which is identical to Minolta’s A-type. To fit the lens, align the orange dot with that on the camera body, and twist clockwise.
The gold contracts are used for communication with the camera, the black metal lever controls the aperture, and autofocus is driven from the camera body via the screw coupler; just over 2 1/4 turns are required to travel from infinity to closest focus.
|The filter thread is 62mm, and does not rotate on focusing, which will be welcome news to filter users.|
|The bayonet fitting, petal-type ALC-SH105 is supplied as standard. It’s reasonably solidly made of black plastic, and reverses neatly for storage.|
|The zoom ring rotates 70 degrees clockwise from wide to telephoto, with markings at 16, 24, 35, 50, 70 and 105mm. The grip is 18mm wide, but the zoom action somewhat stiff and uneven. The lens extends 52mm on zooming from 16-105mm, and there is a slight lateral ‘play’ of the lens barrel at full extension; nothing to worry about in normal use.|
|‘The 16mm wide focus ring rotates just 45 degrees clockwise from infinity to 0.4m, and is distinctly stiff in action making precise focusing tricky. A distance scale is provided with markings in both feet and meters, but there’s no depth-of-field markings or infra-red correction mark.
As is common with internal focus zooms, the angle of view gets noticeably wider on focusing closer.
Reported aperture vs focal length
Here we show the maximum and minimum apertures reported by the camera at the marked focal lengths.
This lens has an optical design which can only be described as ambitious, and not for the first time we see distinctly mixed results from our studio tests. Sharpness is very good at wideangle but less impressive at telephoto, where results are particularly soft wide open. Chromatic aberration is also an issue at the wide and telephoto ends of the zoom range.
|Sharpness||A spectacular performance at wideangle settings, where the lens is impressively sharp across most of the frame at both the 16mm and 24mm settings, although with rather soft corners wide open. However sharpness falls off towards the telephoto end, especially at wider apertures, where we see quite precipitous falls in the graphs towards the corners of the frame.|
|Chromatic Aberration||As usual, chromatic aberration is most obvious at wideangle, with strong red/cyan fringing visible at 16-24mm. At intermediate focal lengths CA is generally well controlled, before creeping back at the telephoto end; there’s a little red/cyan fringing at 70mm, and it becomes clearly visible again at 105mm. The fringe widths also tend to increase noticeably on stopping down.|
|Falloff||We consider falloff to be a potential problem when the corner illumination is a stop or more lower than the centre. As is common for wideangle zooms, falloff is visible at the widest settings, with a maximum of 1.7 stops wide open at 16mm; stopping down to F6.3 or smaller will essentially eliminate the issue. At 24mm and beyond falloff is not an issue. Not a bad performance at all.|
|Distortion||Distortion is (as always) most pronounced at wideangle, with 1.7% barrel at 16mm. This is also a complex ‘wave’ type distortion, with re-correction towards the corners, which makes software correction relatively difficult. The rest of the range shows pincushion distortion, with a maximum of 1.7% at 35mm; which might be just about on the verge of visually disturbing for some scenes. Overall a pretty good showing here.|
| A distinctly average performance here, with much lower magnification that the 18-70mm kit lens (as is typical for an internal focus design). Maximum magnification is 0.11x, achieved at a minimum focus distance of about 39.5cm, and a working distance of 21.5 cm from the subject to the front of the lens.
Image quality is very good in the centre even at F5.6, and the corners sharpen up progressively on stopping down. There’s a fair bit of blue/yellow CA visible on our test chart image, but this is unlikely to have a huge effect on real-life shots.
|Macro – 206×137 mm coverage
Distortion: Mild pincushion
Corner softness: Medium
Focal length: 105 mm (157.5mm equiv)
Specific image quality issues
As always, our studio tests are backed up by taking hundreds of photographs with the lens across a range of subjects, and examining them in detail. This allows us to confirm our studio observations, and identify any other issues which don’t show up in the tests.
This lens has a distinct propensity to display soft corners wide open, as revealed by our studio tests, so the question is whether this is a practical issue in real-life shooting. It’s worth highlighting the visual difference between the effects at wideangle, where sharpness falls abruptly in the extreme corners, and in the mid-range of the zoom, where there’s a more gradual drop off in performance across the frame from centre to corner.
The 100% crop below is taken from the lower left of the image (not quite the extreme corner) at 16mm F3.5, and shows a marked drop in resolution even across a 240 x 180 pixel sample, with individual blades of grass reasonably defined in the top right, but reduced to mush in the lower left. In fairness it must be said that this only affects a small proportion of the frame (and where there’s unlikely to be any key image content); it can also be addressed by simply stopping down to F8 or so, which you’re likely to be doing with a wideangle anyway. However if you have a pathological dislike of soft corners wide open, this isn’t the lens for you.
|16mm F3.5, Alpha 700||100% crop|
This sample at 35mm and F5.6 illustrates the more gradual drop in resolution across the frame seen in the middle of the zoom range at wider apertures. Here even the top edge of the frame is slightly soft compared to the centre, and the extreme corner distinctly blurred. Again things sharpen up on stopping down to F8-F11, so it’s not too difficult to work around, but we’d generally expect to see sharper results than this from a premium lens.
|35mm, F5.6, Alpha 700||100% crop, centre|
|100% crop, top centre||100% crop, top left|
We expect to see chromatic aberration at the wideangle end of a lens of this type, but what is less common is the intense red/cyan fringing this lens also displays at telephoto. Fortunately, due to the near-linear shape of the CA curves (as measured in our studio tests), the fringing is easy to eliminate if you are prepared to shoot RAW and process using a converter with CA correction capabilities; for example using our standard, Adobe Camera Raw, a setting of + 40 red in the lens correction tab worked well.
|F8, Alpha 700||F5.6, Alpha 700|
|100% crop, camera JPEG||100% crop, camera JPEG|
|100% crop, RAW, ACR with CA correction||100% crop, RAW, ACR with CA correction|
One area where the Sony 16-105mm excels is in its handling of flare. Even with the sun placed in the corner of the frame at 16mm, it gives little in the way of flare patterns, which is unusual for a design with so many elements. It deals well with strong side- or back-light too, with minimal loss in contrast even when the sun is directly impinging on the front element but out of frame.
|16mm F8, sun in corner of frame||70mm F9, strong backlight|
Background blur (‘bokeh’)
One genuinely desirable, but difficult to measure aspect of a lens’s performance is the ability to deliver smoothly blurred out-of-focus regions when trying to isolate a subject from the background, generally when using a long focal length and large aperture. Sony make a selling point of this lens’s circular aperture, which is supposed to ensure smooth background blur.
In practice the lens can certainly produce some pleasant transitions between areas of the image which are in and out of focus, but bokeh is not particularly smooth, with sharply delineated edges to specular highlights. It’s not at all bad, but not that special either.
|105mm F5.6, Alpha 700||100% crop|
|105mm F5.6, Alpha 700||100% crop|
Conclusion – Pros
- Hugely useful wide angle to telephoto range – arguably the most flexible currently available
- Extremely sharp at wide angle
- Impressive resistance to flare
- Small size and lightweight
- Good build quality
Conclusion – Cons
- Chromatic aberration at both wideangle and telephoto ends
- Extremely soft in the middle of the zoom range at wider apertures
- Somewhat soft at telephoto
- Stiff manual focus ring with excessively short travel
The Sony DT 16-105mm F3.5-5.6 is a lens which certainly promises a lot, with a tremendously useful zoom range wrapped up in a surprisingly compact body. It may not at first glance have the headline-grabbing attraction of those superzooms which sport 200mm or even 250mm telephoto ends, but I’d venture to suggest that as a single-lens solution, it’s more useful for the majority of general-purpose work, with the additional width more than compensating for the shorter length (it’s much easier to crop the occasional long shot than stitch a wideangle composite). And in real world shooting it generally delivers on its promise, producing attractive results across a wide range of shooting conditions with a minimum of fuss.
Of course every silver lining has its cloud, and the compromises which are inevitable in such an ambitious design aren’t hard to find. Chromatic aberration at wideangle and telephoto is very pronounced, and because the fringing is red/cyan in colour, it shows up frequently in real world use. The corners are soft wide open at 16mm and 25mm, but this is ultimately a relatively trivial issue in photographic terms; stopping down to F8 is all that is needed to sharpen them up. More worrying is the loss in resolution across most of the frame at larger apertures in the middle of the zoom range, where you’ll need to use F8 or F11 to get the best results. (To be fair, this is not exactly the first zoom which works best at these apertures, and it won’t be the last either.)
This therefore is a lens which will repay you with good results once you get to know and appreciate its foibles, and even put them to good use – for example that mid-range corner softness could be useful when shooting portraits, to help emphasize a subject placed towards the centre. And it must be said that when this lens is good, it’s very good indeed, easily providing sufficient resolution for the Alpha 350’s 14.2 Mp sensor at optimal focal lengths and apertures. Crucially in side-by-side comparison shots, it’s streets ahead of the 18-70mm kit lens, and therefore an ideal upgrade for users seeking a more capable general purpose lens.
In summary, this is a very good lens for Alpha users. The versatility of the focal length range goes a long way towards making up for the inevitable optical compromises, and as such the lens easily earns our recommendation.
|Detail||Rating (out of 10)|
|Ergonomics & handling||7.5|
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Sony DT 16-105mm F3.5-5.6 Review Samples
24 images • Posted on Mar 13, 2008 • View album