Macro question

[Lynton]

Noticed on a lot of macro lenses they state magnification of 1:2 or 1:1 - obviously the latter is life size - but how does this relate to reality?

I.e. Suppose I have a 1:1 macro lens and I take a picture of, say, a Ladybird. Where does the lifesize bit come into it, as obviously if i am close enough and fill the frame on a 14Megapixel camera - it's going to be a lot larger than lifesize - or am I missing something? (Probably the plot!)

 

[Nawty]

It's the size of the image on the sensor.

 

[Dogfish_magnet]

Take a picture of a ruler at 1:1 you see

and at 1:2 you see

so at lifesize you see The same width on the ruler as the physical width of your sensor - if I'd done this on a FF 1:1 on the ruler would be 36mm

 

[Lynton]

Cheers - that seems quite simple.

I assume that's at the minimum focussing distance.........

 

[Nawty]

Yeah, but when you get down to these distances you tend to speak terms of magnification rather than focal distances. They are interchangeable terms though...

 

[Lynton]

Yeah, but when you get down to these distances you tend to speak terms of magnification rather than focal distances. They are interchangeable terms though...

Cheers - I get it now..... Was just one of those things that was bugging me!

 

[squishy]

One thing sometimes people get confused on is how 1:1 works with different sized sensors.

Some people will tell you that a 1:1 lens on an APS-C body will give you 1.6:1, because of the crop, but it's actually still 1:1, because the image being projected onto the sensor is still life size, it's just cropped more by the FoV.