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Selecting the Studio
Zoom |
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Criteria |
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The Short List |
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What I needed was the
on-digital kinda no-man's-land zoom range, the 28-70mm (42-105) to use
as a studio lens. Size and AF speed was not overly important,
although an AFS/HSM would have been an advantage. |
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I needed the best
overall sharpness in that desired range with a favour for the longer
end, but also the best consistency, so good edges was important. I
don't need the best lens at f2.8 so I've only looked at the range from
f4-8. |
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I eliminated the Nikkor
28-70/2.8 & 24-70/2.8 on price, also the Nikkor 24-120 and 24-85 on
their CA figures alone! So that leaves these three main
contenders. |
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The Resolution Tables |
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The Vignet/CA Table |
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The Lenses |
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The resolution tables
show the centre and edge figures at f4, f5.6, and f8. I've
highlighted in red the 'winner' in each comparison. |
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The final table shows
the vignetting figures at f5.6 at various focal lengths |
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Nikkor
18-70mm f3.5-4.5 AFS D
Sigma
24-70mm f2.8 EX DG Macro
Tamron
28-75mm f2.8 XR Di LD |
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The Decision
In terms of
resolution at the 40-75mm end there is a clear winner on paper, I've
also had the KonicaMinolta version of this lens in the past and been
impressed enough with its sharpness. I've also had the Nikkor and
the Sigma shown here, no complaints from any of them. Vignetting
and CA are a bit more of a mixed listing with the Tamron being first or
second place most of the time. So, with none in the bag and the
choice before me: I'll take the Tamron 28-75mm f2.8 XR Di. |
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