Working out Macro power

[boolean]

Hi,
Probably being dense but to work out how powerful a mcro lens would I photograph a ruler as close as possible and look at the length of the mm captured from edge to edge then compare this to the width of the sensor ?
Thanks

 

[sbowler579]

Crop sensor or Full frame?

 

[sbowler579]

HERE is a sensor size guide.

 

[sbowler579]

AS to the power I would say 1:1 or lifesize,most dedicated macro lenses will shoot at lifesize.

 

[The W]

If you photograph the ruler, the magnification is (width of sensor) / (width of visible ruler). So if you're shooting with a Canon APS-C sensor, 22.3mm wide, and can see 7.5mm of ruler, then the magnifcation is 22.3/7.5 = 2.97, ie x3 or 3:1.

 

[boolean]

Yes it's a crop sensor - Canon 50D I found that was 22.2mm wide, I can get in so that 12.5mm fills that width, just wanted to work out what it was.

 

[boolean]

Thanks Paul so I make mine x1.78

 

[The W]

So 22.2 / 12.5 is a macro ratio of 1.8:1

 

[boolean]

Thats using a 70-300 Tamron SPVCUSD - not macro with a Raynox DCR-150