true macro lens

[chrise17]

The canon ef 100mm macro lens will it still offer 1:1 true macro images on a cropped bodyas does the ef-s 60mm macro?

[DrJon]

Re: true macro lens

Yes

(I was going to stop there, but there is a minimum post length.)

Think of where the sensor is in the camera as the wall of the room you're in. There is a lens inserted through the other wall that projects a picture on the wall of something in the next room. If the lens is capable of 1:1 macro then at its closest focus distance you should get a picture on the wall the same size as the object (say a person in that next room).

The sensor size is just how big a chunk of the wall is sensor, rather than wall. So for example a full-frame sensor might be 36" x 24" (scaling from mm to inches for this example) and a crop sensor 22" x 15" (with the same centre point), so they see different amounts of the picture, but it is still 1:1 for both of them. I hope that makes sense. Note the crop sensor will probably have smaller pixels so is capable of showing more detail, if the lens and everything else can provide it. (For example 550D/60D/7D pixels are 4.3um across, 5DmkII/1DsIII are 6.4um.) I'll get in trouble if I don't mention that usually if you move closer with the full-frame camera, so the picture has the same content, then that should show more detail, due to the larger pixel count, except you can't if you are at the minimum focus distance so the smaller pixels do win (depending on lens, etc. this could go on forever, perhaps I should have stopped at "yes" :-)

BTW the two 100mm macro lenses are excellent.

John