The Sigma hunted focus more. It rocked back and forth like it
couldn't make up its mind. But atleast one of the two positions
that the Sigma couldn't decide between yeilded a sharp picture. The
Tamron locks target, and then does not move that much when the
button is half-pressed again. I'm not sure though that that is to
the better, because as I have found, even though the Tamron has
locked focus, the results can come up blurry due to misfocus.
(I'm mostly talking f/2.8 here, and perhaps my copy had a slight
front focus issue)
Flare resistance is not a concern of mine, so I never tested that,
and now I have returned the lense.
Why did you return the lens? Were you testing it? Or did you buy
it and decide that you didn't want it?
Yes, I bought it and decided it was not for me. For now atleast.
If this isn't the case, then which one do you prefer? The Sigma or
the Tamron?
It's a tough question.
The sigma has a warmer color cast than the Tamron which is more neutral, so a + for the Tamron there. (a matter of taste, and correctable when shooting RAW)
The Sigma seemed to me to be sharper at f2.8, especially at 50mm, but I guess later reviews can settle that. The center sharpness seemed to be better with the sigma, BUT the Tamron has considerably better edge and corner sharpness.
AF issues I've allready mentioned previously. The tamron is a bit noisier.(or perhaps it's only that the sound is more high-pitched)
I guess It comes down to what one intends to use the lense for. For me, center sharpness, and decent sharpness at 2.8 is important, especially at 50mm for portraits - and I guess many would say: "well, then get a prime", but I've used the Sigma,and become used to a handy zoom. I guess I expected more from the Tamron.
Also, with the Tamron, while making the test (using 350d, MLU, 2 sec timer, Av-mode) I got "error 99" at least 6 times, forcing me to remove and replace the battery. Never happened before.
weird.
Also, barrel distortion seemed to be worse on the Tamron - shooting pics of artwork even at 38mm resulted in (slightly) bent frames near the edges.
well, maybe It wasn't a tough question after all - I'd say I preferred the Sigma.
I've got a Tamron 28-75 that I like, other than the fact that 28mm
isn't wide enough. I'd like to replace it with the new 17-50, but
only if its performence is comparable. My copy of the 28-75 is
somewhat soft at f/2.8, but is really great at f/4 and above. So
I'm not demanding perfection at f/2.8. But I don't want to see any
erractic focusing that produces images that are grossly OoF at
f/8.0, because my 28-75 isn't erractic. So long as I avoid f/2.8.
Wayne
Remember, I might have gotten a not so good copy. The overall sharpness when stepped down a bit is excellent, really good at f4, and it shines at f5.6. I presume it is comparable with the 28-75 which I have heard a lot of good things about. I am actually considering getting that one instead.
The only thing is I've read that AF at 28mm 2.8 is very poor, throwing the focus off totally in some cases. What's your experience?
I dont think I'd miss the wide end that much.
pusseapa
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