Quote Originally Posted by Common Rose
Was reading the HK book. It said, "A 100mm-macro lens with f2.8 aperture value is most suitable for close-up photography. ... If one wishes to obtain the macro effect without getting too close to the subject butterfly, options are either to use a 200mm macro lens, or use a 2x tele-converter with the 100mm macro lens."
the focusing distance for the 90/100/105 is roughly 12cm? for a 1:1 shot, yes, you can crop down and you do not require faster shutter speed like the 180mm, weight is also easier on the user.. problem is getting close to the subject. Adding TC will lose sharpness and lose of 1 stop for 1.4x and 2 stops for 2x

but i still prefers the working distance of the 180mm, though heavier.. after a while, you wun notice it after mounting on a monopod

if budget aint a problem, go for a used 180mm