Jason. Just a point on nomenclature...
The ratios 1:1, 1:4, x:y, etc refer to "image size - to - subject size".
That is the same as saying "subject size - to - reciprocal of image size".
Sigma give a "maximum magnification" size for their
lenses.
That 70-300 you're talking about (which I have, BTW),
listed here,
shows it to be 1:4. Ie, a full size subject will be 1/4 size on the sensor.
Confusing? It can be.
So, where the leading figure is larger, such as 2:1, that means the reproduction size at the sensor is
TWICE life size of the subject.
OK, just by-the-by. You can now cease to be confused.
- No, wait! Don't get confused by the "crop factor" of a camera sensor. People somethings think that on a, say,
APSC camera with a 1.5 crop factor, they will get a 1.5:1 magnification using just a 1:1 macro
lens. This is not correct,
as the ratio, x:y always talks about image and subject sizes - nothing else. (Ie, NOT about "angle of view".)
Now you can take a Bex and have a good lie down.
Am.