Sony 18-250mm f/3.5-6.3 DT SAL-18250
Sony 18-250mm f/3.5-6.3 Review
April 27, 2008
by Andrew Alexander
Released by Sony in October 2007, the 18-250mm ƒ/3.5-6.3 offers slightly more telephoto reach than Sony's other ''vacation'' lens, the 18-200mm ƒ/3.5-6.3. The design and specifications of the 18-250mm bear an eerie resemblance to the Tamron 18-250mm ƒ/3.5-6.3, which we have also tested.
The 18-250mm ƒ/3.5-6.3 was designed to fit the imaging circle required by a digital SLR camera, thus there may be some hard cropping if the lens is mounted on a Minolta film body (or a Sony full-frame camera). The lens is a variable aperture lens, in that as you increase the focal length, both the maximum and minimum aperture sizes decrease. The following table reflects the change in aperture with focal length:
|Focal Length (mm)||18-23||24-34||35-54||54-74||75-149||150-250|
The lens takes 62mm filters, comes standard with a petal-shaped lens hood, and is available at the time of writing for around $550.
Considering its ''jack-of-all-trades'' design philosophy, the 18-250mm ƒ/3.5-6.3 generally provides above-average results for sharpness. Optimal sharpness is seen at ƒ/8-11 regardless of the focal length. Most lenses can provide an excellently sharp image in the mid-range of their focal length and aperture spectrum, and the Sony 18-250mm is no exception; the real determination of the lens' performance is in the assessment of the quality offered outside of this ''safe'' zone.
The 18-250mm provides surprisingly good results for sharpness stopped down to just ƒ/4, though only in the wide to mid-range zone of focal lengths. Wide open and wide-angle (ƒ/3.5, 18mm) there is a good ''sweet spot'' of sharpness, easily half the center of the frame, with corner softness only hitting or slightly exceeding two blur units. Stopping down to ƒ/5.6 gives noticeably better results across focal lengths up to 70mm, and by ƒ/8 or ƒ/11 the lens is as sharp as it can get regardless of the focal length.
At 70mm and longer, performance at ƒ/5.6 shows only a small sweet spot of sharpness, and increased corner softness (~4 blur units at 100mm). At 200-250mm stopping down to ƒ/11 is necessary to achieve critical sharpness, and even then we are seeing only 2 blur units at best, and 3 in the corners.
Diffraction limiting sets in at ƒ/11 but is more visible at ƒ/16 across all focal lengths; apertures smaller than ƒ/16 producing increasingly soft images above 18mm, reaching 10 blur units from corner to corner when set to ƒ/40 at 250mm.
In summary, the lens performs best at 70mm or below when stopped down to between ƒ/5.6 and ƒ/11; very good results (with some traces of corner softness) are attainable at ƒ/4 when set to between 18-34mm. Above 70mm maximum sharpness is only attained at ƒ/8, even ƒ/11; to get usable results a high shutter speed is required, which necessitates either bright conditions or a higher ISO. It's not the best performance we've seen from a lens, but given the class of lens it represents, it's definitely above-average performance for sharpness.
The lens does not offer particularly good resistance to chromatic aberration, but then, there are 16 lens elements in the optical design for light to pass through. Similar to the lens' performance for sharpness, CA resistance is better at 70mm and below, where CA manifests more with the lens used at its widest apertures. Interestingly, the lens seems to be optimized for CA tolerance at 18mm, with a fairly constant (and low) test result for CA presence. Above 70mm, CA is noticeably visible in the corners when used at the wider apertures. To the lens' credit, CA isn't particularly visible in the central region of the frame.
There is some evidence of light falloff in the corners when the lens is used at 18mm, and the worst effects of this are represented at ƒ/3.5, where an image will be just over 3/4 of a stop darker in the corners than the center. At other apertures, minimum light falloff will be just under 1/3 of a stop. This corner darkening isn't as much of a factor at other focal lengths and apertures - stopping down to ƒ/8, light falloff is less than 1/4 of a stop.
Distortion is fairly complex for this lens. At its widest angle the distortion is uniformly barrel, and noticeably significant; around 1.25% in the corners. By around 30mm the barrel distortion in the corner regions of the image disappears, turning into pincushion (''squeeze'') distortion. This pincushion distortion shows its most noticeable results at 35mm in the corners, at -0.6%. Meanwhile, central distortion remains barrel, at 0.2%.
Getting straight lines in real life to be straight lines in images made with this lens may be a complicated affair in post-processing. This isn't much of a problem with the focal length set at 30mm or below, as both the center and the corners are barrel-distorted. However, after 30mm, the combination of barrel distortion in the center of the image and pincushion in the corners means if you correct for one, you will accentuate the other.
The 18-250mm ƒ/3.5-6.3 focuses relatively slowly, but then this is a mechanically-driven lens that has to push a fair amount of glass around. On an A700 focus operation was fairly loud, with the noise of whirring gears.
The lens isn't designed for macro work, but with a minimum focus distance of 45cm (18'') and a magnification ratio of 0.29x, it's not impossible to take fairly good close-up shots.
Build Quality and Handling
The Sony 18-250mm ƒ/3.5-6.3 is solidly built for a consumer-level lens, with a metal lens mount but plastic filter threads. A distance scale is etched into the focus ring in both feet and meters. The zoom ring is fairly hefty with a finely-ribbed texture that's 1 1/4 inches wide and easy to grab on to. A quarter-turn takes you through the entire focal range, and the zoom operation is fairly smooth. Zoom creep isn't a factor with casual use: further, the lens can be locked to the 18mm position with a dedicated switch to ensure it's never a factor. Extending the focal length to 250mm adds about three inches to the overall length of the lens. The lens uses an internal focusing system, so the length won't change during focusing.
The lens doesn't offer full-time manual override, which can be an advantage or a disadvantage depending on your point of view; to set manual focus for the 18-250mm, you must switch the camera body to the manual focus mode. The focus ring travels about 70 degrees, and is less than an inch wide with the same thinly-ridged texture. The front filter ring doesn't rotate during focusing or zooming, which is essential for easy use of a polarizing filter.
The petal-shaped lens hood adds 1 3/4 inches to the length of the lens and it does reverse and attach solidly to the lens for easy storage, but affixing it this way makes it practically impossible to use the zoom or focus rings.
Tamron 18-250mm ƒ/3.5-6.3 Di II LD Aspherical IF Macro AF ~$450
Based on a comparison of lens specifications, it's hard to dispute the notion that the Sony 18-250mm is a re-badged version of the Tamron; comparing the test results seems to provide more evidence to support this contention. Profiles for sharpness, chromatic aberration, vignetting and distortion are similar, but to be fair, the Sony did test slightly better. User reviews suggest the Sony 18-250mm focuses much faster on an A700 body - but not on an A100 body. Otherwise, everything is the same but the price.
Sony 18-200mm ƒ/3.5-6.3 DT SAL-18200 ~$500
Our sample of the Sony 18-200mm lens showed sharper results on the telephoto end than the 18-250mm; chromatic aberration is more prominent, vignetting is more of an issue, and distortion is about the same.
Sigma 18-200mm ƒ/3.5-6.3 DC ~$320
The Sigma comparable to the 18-250mm is slightly sharper in the center of the frame, but there are more potential situations with corner softness. Chromatic aberration is a bit more dependable: virtually non-existent in the focal mid-range, but noticeable in the extreme wide or telephoto end. Vignetting and distortion are similar. Much less expensive.
The Sony 18-250mm shows its best performance when set to between 18-70mm; after that, issues with sharpness and chromatic aberration make it just a bit less useful. As far as vacation lenses go, if you find yourself shooting more at the telephoto end than the wide end, you're better served by the Sony 18-200mm if you're brand-loyal, or the Sigma 18-200mm if you're not, as these lenses are significantly sharper at 200mm.
The choice between the Sony and Tamron version of the lens I think comes down to sample quality, and what kind of deal you can get. Though if you're an A700 owner, the feeling is that the Sony version of the lens focuses significantly faster on that body, which could be an important deciding point for some. On its own merits, the Sony 18-250mm represents a good demonstration of managing design concessions. It's a compact lens that offers a very useful range of focal lengths, and while it can't hope to be as sharp as more dedicated lenses, it's the lens that will go everywhere, and will provide acceptable performance.
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 18-250mm f/3.5-6.3 DT SAL-18250
Sony 18-250mm f/3.5-6.3 DT SAL-18250 User Reviews
8 out of 10 points and recommended by thubleau (2 reviews)excellent lens on the right bodynon so far
Another misleading test review..........when will reviewers ever learn that using lenses such as the 18-250 become totally irrelevant once you use this on abody that can do it justice.reviewed June 23rd, 2012 (purchased for $575)
For instance try this lens on say the Sony a57 and you will see the results are quite difference
Most modern cameras use lens profiling, unbelievable processors and great Apc size sensors which all play a major roll in the final results of just another ordinary lens.
Thats correct, they remove distortion,pin cushioning, ghosting and even abberations so what happens is this.
You pay a lot less for a cheap lens and get amazing results.
I tested this lens against highly rated L enses including the 17-40 24-105 and the 70-200 all on my full frame sensored 5D MK2 and the results were so close that i realised it is a total waste of money buying expensive glass for APC-S SENSORED CAMERAS.
There is only a limited amount of resolution that can be extracted from these small sensors..........its not alimitless exercise as once you reach a certain point it becomes impossible for the sensor and the lens to extract anymore resolution.
Camera bodies carry out a very important part in this process with the latest bodies even building resolution beyond the actual physical capabilities of the lens.
This is of particular importance if you have no need for apertures lower than f/4
as historically it is the lenses at this f stop that are cheapest to buy.
With higher iso performance in modern day cameras its just not necessary to buy lenses of supposed technical superiority when you print up to 8X10 as you will not see any difference.
9 out of 10 points and recommended by dfwatt (3 reviews)1) great walkaround lens 2) good sharpness if stopped down, esp at wider end 3) good value1) not great sharpness once above 120mm even if stopped down - by 200mm soft even at f11
Pro:reviewed January 16th, 2012 (purchased for $350)
1) 14 x range from moderate wide angle to moderate telephoto makes this a very convenient package
2) good but not great sharpness, esp. if stopped down a bit (f5.6 up to about f8/f11 where it reaches its max sharpness), and sharper at wider angles
3) good build quality and solid construction - won't compete with either Carl Zeiss or G series pro lenses, but still quite well made and good value
4) fast focusing (at least for big lens)
5) Not bad CA, distortion and vignetting (UPDATE - when used with the A77 or A65, these are effectively removed by the firmware-based corrections, which are quite effective in cancelling out CA, and corner shading effects are virtually eliminated too. (See my Amazon review of the Alpha 65)
1) Not impressive sharpness at telephoto end - wouldn't recommend if you plan on shooting a lot there (120-250mm), even stopped down
2) Some troubles with chromatic aberration, esp. again at telephoto end (but again virtually eliminated by A65/A77 firmware v 1.04)
3) Heavy (might overwhelm small, light camera bodies like the A55/A33/A33 - works better with bigger bodies like A65 and up)
4) Wish it traded some of its reach at the telephoto end for going down to 16 mm at the wide-angle end
I was initially torn between buying this lens with an A55, or buying the 18-55 mm standard kit lens and having a little bit less flexibility but a lot less weight. Although the weight is sometimes a burden, I certainly appreciate the 14 X zoom range, from moderate wide-angle to pretty decent telephoto without having to change lenses. I haven't seen a lot of problems with chromatic aberration, but I haven't shot too many exposures with the lens all the way out (largely because it's just too soft there). These large range zoom lenses are compromises between the convenience of having such a wide range of focal lengths, vs. the sharpness and accuracy of a single focal length lens. Overall, and on balance, I recommend this lens to people who value not changing lenses (nothing worse than missing a great shot while you're fiddling with your equipment), and to those not shooting at the long end of the lens much.
If you are thinking about getting this, I recommend getting it with the camera and saving some major money over buying it later. At $599 (list), it's not cheap. Its effective cost when bought with the A55 camera body is a lot less (~$300) - this is a great deal (typically $1050 for this lens and the A55). It is a major improvement on its predecessor (the 18-200 mm), and generally pretty sharp for this type of lens.
8 out of 10 points and recommended by touristguy87 (33 reviews)great range, nice and sharp even at 250mmblooms a lot, with strong internal reflections (at least on an a700)
...this is a magical little lens and if wasn't for the strong haloing around lights at night, I would have no problem recommending it.reviewed February 10th, 2008 (purchased for $500)
It is very sharp even at full zoom, sharp enough to shoot without concern at F6.3 maybe even F5.6, at F8 is it almost perfect. I have gotten some 200mm shots from it on a Sony a700 at IS0250 that were literally the best-looking photos that I've ever taken.
The one thing, the SSS system does make the Sony lens line seem almost too simple :) either the lens is good or not, and really the problems are more with the cameras than the lenses. but I know for sure taking the same shot with a D300 and the Nikon 18-200VRII that it is not as sharp wide-open but between the camera and lens, reflections are much better controlled.
So in my opinion it's a great day lens that can survive at night if you aim it wisely.