Quote:
Originally Posted by rsbfoto
Hi,
Just thinking loud which means that the word Macro says it all.
I just looked on the focusing ring of my Canon 180mm f3.5 and saw that the focusing ring is quite open when I focus in the near range eg. the numbers do take up a lot whole of the scale in the near focusing range and less in the far focusing range.
What I want to say is that it will be difficult to focus a Macro lens in the infinity region but it is easy to focus in the near range ...
Think about that
regards Rainer
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umm I think there's some confusion here.
The Canon 180mm is a true macro lens but it also is a 'normal' 180mm prime lens able to focus to infinity for telephoto shots.
It can be used for astro imaging when set to infinity (or approx infinity) and aperture adjusted to almost wide open.
It can also be set to macro mode (true macro mode) and will focus up close for beautiful 1:1 life size shots.
The reason, I suspect, Robert (OP), asked specifically about macro lenses for astro is that he wants to 'kill two birds with the one stone'.
He would like to use the same lens for macro imaging
and astro imaging, cutting down the number of lenses he needs to buy.
Hence why I recommended the list of true macro lenses that are available from Canon.
Unfortunately I haven't had to opportunity to try any macro lenses from other manufactures so I couldn't comment on other brands.
But you certainly can use these macro lenses for astro when focused on infinity.
The only lens I know of that can't be used is the highly specialised Canon MP-E 65mm 1:5 macro lens.