Using Supplementary Lenses in the Field

Standard lens 105mm + Canon 500D Close up lens (+2 diopter) i.e. max lens to subject focusing distance 500mm at infinity setting 160 mm at 'macro' setting

Common name: Marmalade Hoverfly
Species: Episyrphus balteatus
Family: Syrphidae
Exif info: ƒ16 1/100 sec pop up flash
Helophilus pendulus © Phil Gee
For more information on Hoverflies click on the images and it will link you to the Dipterists Forum,
Hoverfly recording scheme.
Helophilus pendulus © Phil Gee

Close-up 'magnification' is when the object is reproduced at less than life size on the Sensor or Film. the range from 0.1x or 10:1 to the start of the true Macro at life size 1x or 1:1
However it is the practice of some manufacturers to mark 'Macro' on lenses which is a terminological inexactitude as on the 105mm lens I used.

Focusing as close as possible in the so called 'macro' range with no supplementary gives a magnification of:
Object being photographed is 88mm wide its Image is reproduced on a chip 22mm wide,

Image /object = Mag = 22/88 = 0.25x or 4:1 NB 4:1 means the object(or subject) is 4x bigger than the image

With the addition of a +2 diopter a subject 56mm wide fills the frame resulting in a 'magnification' of

Image 22mm / object 56mm = 22/56 = 0.393 say ~ 0.4x or 2.5:1

True Macro starts at life size i.e. a 22mm subject is reproduced at 22mm on the chip hence 1:1 or 1x to 50x