Which Macro lens for Canon ?

[MeadsMan]

Silly questions,but am I correct in saying the canon 100mm can achieve the same size image as the Sigma 150,you just need to be 5 cm`s closer ? How good is the 100mm Macro with no attachments for insect photography,I do not like to heavily crop images,so with no cropping and at it`s closest focusing distance how big would a wasp or similar size insect look in the frame if un-cropped,can anyone post samples of an un-cropped image of a common species taken with the Canon 100 mm ?

[squishy]

Yes, the 100mm will produce exactly the same ratio as the 150mm, you just have to be closer. 5cm is just at 1:1. When you add in the lens hood (the canon's is larger), the difference is even more in favour of the 150mm.

5cm is just the difference at closest focus. The difference becomes larger and larger at longer distances, a big advantage for stuff like butterflies.

Worth remembering you can also put a 1.4x on the sigma to get a 210mm macro with still excellent IQ, whereas to get that focal length with the 100mm you'd have to use a 2x converter (and a 2x converter on the sigma gives you a 300mm macro which supposedly still gives high quality images when stopped down to f/8 or smaller. I've even seen high quality images from a siggy 180mm (optically performing identically to the 150mm) with stacked 1.4 and 2x converters).