Tamron AF 17-50mm f/2.8 SP XR Di II LD Aspherical [IF]
http://www.photozone.de/canon-eos/2...ii-ld-aspherical-if-canon-test-report--review
Verdict
The Tamron AF 17-50mm f/2.8 XR Di II LD Aspherical [IF] may have one of the funniest names around but the performance of the lens is serious at least regarding resolution where it was capable to deliver some of the best MTF50 figures to date. On the downside the very high field curvature at wide angle settings can be a problem in some situations (flat or very deep scenes at large aperture settings). Vignetting and distortions are about average for a lens in this class. CAs could be a little better at 17mm but otherwise the issue is quite well controlled. Mechanically the lens isn't top notch but it compares very well here to other third party lenses. Thanks to the very moderate price tag the lens is highly attractive and definitely worth a deeper look when shopping for a quality standard zoom lens for your APS-C DSLR.
Optical Quality: 4/5
Mechanical Quality: 3,5/5
Price/Performance: 5/5
http://www.photodo.com/topic_162.html
Verdict
With the exception of the distortion at the wide end, this is a very competent lens and a considerable jump up from the general standard of kit lens that it would replace. There is little else that lets it down and good resolution across the frame that is acceptable even when the lens is used wide open commend it. The only other place it could be improved is in the autofocus system where Tamron really do need to get a sonic motor.
In summary, the positive points of the SP AF 17-50mm f/2.8 XR Di11 are:
Good resolution and control of CA
Nice build, an improvement for Tamron
Consistent through the focal range
The negative points are:
Distortion at the wide end.
No supplied case or pouch.
http://www.slrgear.com/reviews/showproduct.php/product/355/cat/23
Botttom Line
At the end of the day, the Tamron 17-50mm f/2.8 Di II strikes us as an excellent option for a "walk-around" lens for your DLSR, one that we think hasn't really gotten the attention it deserves in the crowded lens market. (Highly recommended, in case you were wondering.)
http://www.digicamfotos.de/index3.h...tos.de/dslr-objektiv/details.php?image_id=980
http://www.dslr-forum.de/showthread.php?t=168527
http://www.pbase.com/lightrules/t1750qt
Canon EF-S 17-85mm f/4-5.6 USM IS
http://www.photozone.de/canon-eos/179-canon-ef-s-17-85mm-f4-56-usm-is-test-report--review
Verdict
The EF-S 17-85mm f/4-5.6 USM IS is a lens that promises many things. It is certainly a very versatile standard zoom with a long zoom range and an image stabilizer that can save the day in many situations. However, the build quality is somewhat disappointing and optically it is also something of a mixed bag. The lens is very sharp in the image center throughout the range but at the wide-end the extreme corners leave something to be desired. The 17mm setting also suffers from rather extreme distortions and rather hefty vignetting @ f/4. Finally chromatic aberrations aren't really something to rave about either.
So at the end of the day the lens is a tad better than the cheapo EF-S 18-55mm f/3.5-5.6 but it can't really compete with the new EF-S 18-55m f/3.5-5.6 IS or the EF 17-40mm f/4 USM L. The key feature of the EF-S 17-85mm f/4-5.6 USM IS remains its versatility. While this may sound a little sceptical I should note that I preferred the lens compared to other higher quality options during testing - it is simply a darn convenient lens and despite the flaws it can produce very decent images as you can see from the samples - at least with a little tool support.
Optical Quality: 2,5/5
Mechanical Quality: 3/5
Price/Performance: 4/5
http://www.photodo.com/topic_133.html
Verdict
I can’t help feeling that Canon have pushed the focal range a tad too far at the wide end of this optic because from the 20mm mark through to the 85mm end it is a cracking walkabout lens. It is only the widest few millimetres that let it down a touch. Having said that, with a little judicious work post processing images at that end, they are still very usable. The Image Stabilisation system is a boon in low lighting conditions and made pictures in those situations quite viable. For owners of the cameras that the lens will fit, it is a good addition to the camera bag.
In summary, the positive points of the Canon EF-S 17-85mm IS USM are:
Excellent resolution holds up throughout the focal range.
IS system helps a lot in low light.
The lens makes a good replacement for kit lenses
The focal range ideal for a walkabout lens.
The negative points are:
Distortion is bad at the widest settings and a little CA creeps in.
Front lip is prone to damage.
Hood is an optional extra.
http://www.dpreview.com/lensreviews/canon_17-85_4-5p6_is_usm_c16/
Conclusion - Pros
- Decent build quality - much better than any of Canon's 18-55mm kit lenses
- Very useful focal length range, almost ideal for a walkaround lens
- Highly effective image stabilisation
- Excellent autofocus and manual override
- Consistently high image quality across almost all of the range
Conclusion - Cons
- Poor performance at wideangle, with marked barrel disortion, high levels of light falloff, and intense green/magenta chromatic aberration
- Slow maximum aperture
- Very average close-up performance
Overall conclusion
The EF-S 17-85mm is a major step up from Canon’s EF-S 18-55mm F3.5-5.6 II kit lens, adding an extended focal length range, image stabilisation, fast and silent autofocus with a decent manual focus option, and substantially improved build quality. This makes it, at first sight at least, an ideal all-in-one ‘walkaround’ lens for Canon’s APS-C SLRs, which will cover the majority of photographic opportunities when travelling light.
And to a great extent it delivers on this potential, with good imaging performance over much of its range, especially in that extended telephoto region, plus effective image stabilisation which works as promised. But there’s no getting away from this lens’s Achilles’ Heel, which is comparatively poor optical performance at the wideangle end. Most intrusive is the green/magenta chromatic aberration at 17mm, which is highly visible in a wide variety of shooting situations. Now if you’re only planning on viewing files on screen or making small prints, this may not be a huge problem, but if you are making large prints or viewing at 100% it’s a clear issue. However it can be effectively overcome if you are prepared to shoot in RAW and eliminate the CA in post-processing, using either Canon's Digital Photo Pro (v3.4 or later) or third party software such as Photoshop.
The lens also exhibits significant barrel distortion at 17mm, making it far from ideal for photographing architecture, except perhaps Gaudi in Barcelona, or City Hall amd the ‘Gherkin’ in London. And with its relatively slow maximum aperture, this is also not an ideal lens for low light/indoor photography of people or other moving subjects. It’s important to appreciate that while image stabilisation will allow hand-holding at slower shutter speeds than usual without suffering image degradation due to camera shake, those shutter speeds are still slow, and moving subjects will therefore still be blurred. Likewise the slow maximum aperture will limit flash range, so for this kind of photography, a faster zoom or prime lens will be a better option.
So overall the judgement to be made is whether the attractive feature set of this lens offsets the negatives, and most importantly the problems with distortion and chromatic aberration at wide angle. If you shoot primarily towards the telephoto end, this lens will reward you with excellent results, but if your interests tend more towards the wideangle end of the spectrum and you don't want to shoot RAW, then it may well be a good idea to look away now. However overall it must be said this lens is really rather enjoyable to use; the zoom range is very flexible, the autofocus fast and silent, and the image stabilizer highly effective. So in balance its advantages probably outweigh its disadvantages, and despite its faults this lens is ultimately still one of our favourites for Canon's APS-C dSLRs. Therefore, as long as its limitations are appreciated, it just about earns our recommendation.
GOOD FOR:
Walkaround lens for outdoor shooting and travel use.
NOT SO GOOD FOR:
Indoor available light or flash shooting.
Architectual photography where distortion would be a problem.
Detail Rating (out of 10)
Build quality 7.5
Ergonomics & handling 8.0
Features 8.5
Image quality 7.5
Value 7.0
Recommended (with reservations)
http://www.digicamfotos.de/index3.h...tos.de/dslr-objektiv/details.php?image_id=111
http://www.dslr-forum.de/showthread.php?t=84184
http://www.pbase.com/lightrules/17701785
Sigma AF 17-70mm f/2.8-4.5 DC macro
http://www.photozone.de/canon-eos/312-sigma-af-17-70mm-f28-45-dc-macro-test-report--review
Verdict
Sigma has positioned the AF 17-70mm f/2.8-4.5 DC macro in one of the sweet spots of the market. It is priced beyond the (usually pretty crappy) kit zooms yet it still remains within the reach of budget shoppers. Even better than that it delivers a performance which matches and sometimes even exceeds more expensive lenses. This includes the in-house competition (AF 18-50mm f/2.8 EX) as well as genuine brand lenses (such as the Canon EF-S 17-85mm f/4-5.6 USM IS). All in all the lens has only one really weak spot - 17mm at wide-open aperture where the extreme border performance is soft and vignetting is quite pronounced (but still not worse than the direct competition). At medium aperture settings the delivered quality is very impressive. Combine that with the quite decent build quality and fast AF and it doesn't need a genius to foresee that this lens will be a quite hot seller.
Optical Quality: 3/5
Mechanical Quality: 3/5
Price/Performance: 5/5
http://www.photodo.com/topic_65.html
Verdict
In it’s price bracket, this lens can be considered good. It’s one drawback is the distortion at the wide end, but this is one of the easier problems to cure in digital software and being designed purely for digital cameras with cropped sensors will have no effect on film users. The DC/DG coating that Sigma now uses has gone a long way to improving their lens’s contrast and this shows well in this example. The close focus ability of this offering also helps to greatly increase its versatility.
In summary, the positive points of the Sigma 17-70mm f/2.8-4.5 DC Macro are:
Excellent close focus ability
Good build with no wobbles
Good resolution figures overall
The negative points are:
Barrel distortion at the wide end
AF not as quiet as HSM lenses
http://www.slrgear.com/reviews/showproduct.php/product/349/cat/31
Bottom Line
Overall, the Sigma 17-70mm f/2.8-4.5 DC Macro looks like a great, all-around lens, one that you could leave attached to your DSLR most of the time, and one that beats most manufacturers' kit lenses in sharpness and (particularly) macro capability.
http://www.digicamfotos.de/index3.h...tos.de/dslr-objektiv/details.php?image_id=966
http://www.dslr-forum.de/showthread.php?t=284691
http://www.pbase.com/lightrules/17701785