Originally posted by Class A Interesting. Do you know the Tamron 17-50 f/2.8?
How would you rate it?
Which (not only of the two) do you consider the best zoom?
I am a very biased person and I am similar to some members of the forum here that I do not believe in test charts or photozone.de too much. Like some of the forum members, I rely on gut feeling or my eyes with glasses on of course.
I owned tamron 17-50mm f2.8 on canon mount which really performs well, much better than 16-35 f2.8 L in terms of overall image quality. The barrel distorsion at f2.8 is a little overstatement by most canon or nikon users. I only use f2.8 when I do protraits and it is quite a good performer. Corner sharpness is just another joke people like to dismiss lenses on. Unless it is a german glass like leica or voigltander. Most japanese company lenses are just simply soft in the corner in general which is a signature optical characteristic to them all comparing to german glass maker.
Given my experience so far,
I would love Da* 16-50 for waterfall shots - it works well with polariser or neutral density filter well on k20d. Its high contrast and rich colour above f4 is very good. However, diffraction kicks in early around f11 onwards.
Tamron is probably as good as it can be given its price. I think it probably lacks the lustre of fa limited optical rendering. The subtlety some of us are crazy about that are "popping feel", "micro contrast", "glossy look" etc are probably not that prominent with tamron glass. However, this is the lens I use repeated without a concern to cosmetic damage etc.
sigma 17-70 is really a great lens. I bought it for 300 AUS dollars and sold it for 450 AUS dollars. Second time in my life that I could sell Sigma with a profit margin! If the price is about 1000 AUS dollars or so, I would start to criticise this lens brutally. It takes up flare very well, bokeh are slightly noisy and harsh though. Its build and weight are all not too bad.
Sigma 12-24 is given a good bashing but once in a while, someone will have a good copy. I had a good copy for canon 5D and its soft corners are macroscopicly evident on LCD screen. However, I use this lens for the perspective and I am less fussy about the cost.
I never own pentax 12-24 but some of the test shots I have tried out with local pentax group outing is that it is very prone to purple CA as most of pentax lenses. In Australian sun, this lens re-defines the word - purple. It is a nightmare to rid off these purple bands along edges...
Getting back to Da* 16-50, it is not a bad lens. For the purposes I intend to use this zoom for, this zoom does landscape very well. This zoom is not really a good choice for protrait as some of the autofocus issue and edge sharpness can be a tricky thing. Otherwise, I do not see the big fuss over this zoom besides the quality control thing. I am waiting to sell it though. Da 15mm ltd will serve my need a lot better if it is a limited quality with small size body.