Damn, I should really read these things before I post them.
On 6/15/2012 2:51 PM, P. J. Alling wrote:
Macro in the good old days usually meant 1:2 as a minimum, for maximum
reproduction ratio. When close focusing zooms began to appear it was
misused a lot to describe merely close focusing capability. So don't
be surprised if a lens described as macro is only actually close
focusing (reproduction rations of 1:4 or less in some cases). Some
will be purists and say 1:1, but quite a few dedicated macro lenses
are only capable of 1:2. Some manufactures were sticklers sometimes
and not others. The Vivitar S1 90-180mm f4.5 is labeled as a Flat
Field Zoom, not even labeled close focus, though it's maximum
reproduction ratio at 180mm is 1:2 fully macro by the old
conventions. The Pentax FA 100mm f3.5 Macro has a maximum
reproduction ratio of 1:2, as well as the M and A f4 100mm Macros. So
the answer is it should be at least 1:2 reproduction ratio, some will
say 1:1, but it could be just about anything better than 1:4 or even
less.
On 6/15/2012 2:10 PM, Igor Roshchin wrote:
... Well, I understand the meaning of the word. But what does it
actually mean in the lens designation?
The new Sigma 18-250 lens is called "macro" "with a maximum
magnification ratio of 1:2.9":
http://www.dpreview.com/news/2012/06/15/Sigma-launches-18-200mm-F3-5-6-3-Macro-HSM-superzoom-lens
One of my older version Tamron zooms (70-300/4-5.6) and Sigma 24mm
/1.8 EX DG
are also marked as "Macro".
While Sigma 24/1.8 goes to short focusing distances (about 18 cm / 0.6
ft), Tamron - doesn't (the shortest focusing distance is about 50 or
70 cm).
In contrast, D FA 100/2.8 Macro - has a clear long tail of focusing
distances where you achieve the macro regime.
So, what is necessary and sufficient for a lens to be called macro?
Igor
--
Don't lose heart, they might want to cut it out, and they'll want to avoid a
lengthly search.
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