View Full Version : Magnification ratio

January 5th, 2010, 05:51
It may be interesting to know that apparently Canon has just started revamping it's 70-200 (f/4 non-IS/IS, f/2.8 non-IS/IS) lens line.

At least, that's what thought when reading this:


What I wonder about...in the article they write "The minimum focus distance has been reduced to 1.2m, with a corresponding increase in maximum magnification to 0.21x.".

I know my trusty 55-200mm has a magnification ratio of 0.29 and the 400mm 0.27...but what does it mean in practice ? Do you see real, major differences ? I've read the same about a lens I'm looking for myself, the Sony 28-75mm f/2.8 SAM - the magnification ratio being 'just 0.22'.

A (tele)zoomlens magnifies the things you see by the corresponding factor, but...still...don't get the whole picture about it.

Oh, and I do know a macro lens has a magnification ratio of 1.;)

January 5th, 2010, 08:24
The simplest explanation I have seen is that the maximum magnification of a macro lens is how large the object appears on the imaging sensor. So, for 1:1, it's like you plopped the item down on the image sensor and made a scan of it! By maximum, it means you are right at the minimum focusing distance (close as you can get).