help on macro range

[chriswad]

I have a sigma 70-300m Macro DG lens. It will focus, at closest to 1:2. I also use macro extension tubes. I am wondering what range I am reaching when focusing as close as I can, would it be as large as 1:1?

 

[pxl8]

Set it all up, take a picture of the mm scale on a ruler and divide it by the width of your sensor to get the magnification ratio.

Much easier than trying to figure out the maths

 

[chriswad]

Sounds like a good plan I'll give it a go! Might sound like a daft question but how do I find out the sensor width?

 

[Canon Bob]

Sounds like a good plan I'll give it a go! Might sound like a daft question but how do I find out the sensor width?

It's 22.2mm wide

Bob