Question about Tamron Cameras
Posted by Anonymous on
SOURCE: Tamron 28-75 SP AF XR
You didn't state whether you are using it on an APS-C or a full-frame SLR, but that lens is known to be very soft and unsharp especially at the edges until you stop it down below f4. It also exhibits strong vignetting until you stop it down.
The effects are far more noticeable when using a full frame sensor.
Some production examples will be worse than others, and some users will notice the unsharpness more than others. You clearly find the performance to be unacceptable, but it is mentioned in almost every review of that lens. Your lens is not unique in the weaknesses it exhibits as most lenses perform worst at wide open apertures.
You have discovered one major reason why some lenses are cheaper than others, and why lenses designed especially for low lighting levels are hugely expensive..
Your only real fix is to try and avoid shooting at apertures of f4 and larger. If that's unacceptable to you and you need a lens which performs well in low lighting conditions then you can only return the lens for a refund (much easier if you live in the UK due to the Sale of Goods Act). If you cannot get a refund then I suggest you sell the lens and buy a better quality replacement, or better still replace the zoom lens with fixed focal length prime lenses.
Zoom lenses are always an optical compromise, particularly so with zooms covering the wide to short telephoto range, and now that many dSLR's can produce low noise results at very high ISO settings there's less demand from customers for manufacturers to make lenses which have outstanding performance at wide apertures at higher cost.
Posted on Jul 15, 2011
Tamron makes their lenses with a variety of lens mounts. A lens with a Nikon mount, for example, will not work on a Sony camera. Assuming the lens has a Sony mount then yes, it will work fine on a Sony dSLR.
Posted on Feb 01, 2012
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