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tamron 28-75mm f2.8 for sony/minolta mount
on July 31, 2013
tamron has long been known for spotty quality control. a sample might be total trash or as good as the best canikon can offer. i took a chance purchasing before i could see/test it. it seems there are very few places around the us where one can see/test tamron lenses before buying.
well, it appears i got a lower quality sample. it required good daylight/flash to be sharp, and even in bright daylight images were sometimes distorted. more on the distortion later. i purchased this lens to be my "low light" lens, but this particular sample wasn't up to par.
the "distortion" i mentioned earlier came in several forms. first, when taking a picture of text (for testing) it wasn't sharp fully across the image. the center was fairly sharp, but looking even slightly off center revealed softness. i have an aps sensor camera, and since they only see the center image of the lens, they are supposed to be immune from most of the corner softness. also, around high contrast parts of an image there appear to be tiny "halos" or grain in the image. by high contrast i mean from the chin to the neck on portraits, or black text on white paper for testing.
turning the flash on did help, but why buy an f2.8 lens if you are going to need flash everytime? i also tested at different apertures, but mainly at f2.8. i suppose i simply got a bad copy of this otherwise price/performance leader. note that i mostly saw this distortion by pixel peeping. if you don't care to enlarge to this degree then even poor copies of this lens like what i got will do just fine. if you don't enlarge this much, then an advanced point & shoot is more your market anyway.
don't let my misforture scare you away completely from this lens. if you get a chance to test before buying and are pleased with the results, then by all means this lens is a bargain. however, buying before you can test online is very risky.
i returned the tamron to amazon, which was a painless process. i am waiting for the sigma 18-35 f1.8 to be released in sony mount. this new lens is getting great reviews online. hopefully this lens will be exactly as advertised, and be my "low light" lens.