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Old Jul 25, 2008, 2:07 PM   #11
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robar wrote:
cou;d have sworn i posted here before but.........
how does this stand up to the tamron and the F*300 ??
Hi Roy,

You posed the question in the "dance recital" thread in the main forum, so you're not losing it. . .:-)

The answer is that the jury's still out. . . I really try not to form an opinion on a lens' performance until I've used it pretty extensively in the field. I don't normally shoot much in the way of test targets and such -- what's really important to me is center sharpness, contrast, and focus accuracy and relative speed. So far I've found that the lens is capable of producing as good or better than either the Tamron SP 300/2.8 and the FA* 300/4.5 -- if I do my part.

It's at least as sharp as the Tamron, but I haven't yet been able to dial in the focus adjustment to where I am totally confident -- it seems to focus differently for close and distant subjects, and there seems to be more variation from shot to shot than the Tam and the AFA. I'm assuming at this point that this is mostly due to shooting conditions -- I've taken most of my shots with the new lens handheld, and that can induce focus errors because of my inability to hold the camera steady enough to have it focus on the same area consitently.

I've also made repeated mistakes when using a tripod. With the K20 (much more than with the K10, I've found that turning SR off for tripod use is very important, and I've consistently forgotten to do this when shooting with this lens so far. . . heat of the moment and all that. . . :roll:

Again, so far, the Sigma exhibits about the same CA and PF control as the FA*300 -- which is considerably better than the Tam's, and on the same level as the FA*. The Sigma also seems very resistant to flare, and offers better contrast, especially wide open, than the Tam, but about the same as the FA*.

The real test, for me, will be how well it stands up to TC use. So far, I've used it with the Tamron 1.4x AF TC, and this combo works great. I'm thinking that there's a possiblity that the Sigma 1.4x DG APO AF TC might be a better match, since it was designed to match their EX long teles, so I'll keep an eye out for a deal on one of these -- they're really too expensive if there's no significant performance advantage. Other 1.4x alternatives for stacked use with the AFA would be the Pentax 1.4x S and L, especially the L, but they're pretty expensive too. . .:roll:

Bottom line, at 300mm and 420mm with the Tamron AF 1.4x TC, it's at least meeting expectations so far. If it performs as well as the Tamron with the AFA and a 1.4x stacked with the AFA, then I'll consider it a big bonus.

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Old Jul 30, 2008, 6:28 AM   #12
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Congratulations, Scott, on the new lens. Your shot of the heron is really nice. Looks like you've got a winner in this lens.

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