I'll voice my opinion as well... You can't go wrong with any of the good Macro lenses, Tamron, Sigma, Canon, and Tokina all have outstanding lenses... The question is how close can you, or do you want to be, what is the acceptible amount you are willing to spend, and what is the primary use?? (moving or stationary targets).This will determine the focal length you should get. I have seen outstanding results from all of the lenses made by these 4 companies. I shoot the Canon, 100 and 180 as well as a combination of reversed lens combinations and find I have absolutely no complaints about the IQ of my Canon lenses. The longer focal lengths afford better working distance than the shorter lengths and for nervous bugs it is an advantage. The longer lenses are also heavier but I find the weight helps me hold steady when hand holding the shots. Personal preference on the weight issue.. They are all capable of 1:1 macro . My recommendation would be to go for the 100 range as tubes will increase the size of the subject in the frame and also function nicely for other than Macro applications. I find mine useful enough even with others in the goodie bag that I know I won't part with mine.. Good luck and happy shooting.....Take care....Alex

Hi I would like to thank you all for your input to my initial post and although Its been a long laps in time I finally made up my mind after narrowing my options down to 2 lenses !

I took my time your thinking, Well it took time to get hands on experience with the lenses in question but managed to narrow it down to

Canon 100 mm 2.5
Sigma 150 mm 2.5

The extra distance was the clincher here although the Canon would have given me an excellent portrait lens and its made to fit the Macro Ring Lite MR-14EX ! the working distance and inclusive lens hood and ring mount was worth more purely because I already have good lenses for portraiture “ Canon 24-70 mm 2.5 L and Canon 50 mm 1.4 ” !

The Sigma 150 mm 2.5 is for me as good “ Sharp “ as anything I have tested and is well built with fast AF in all modes. I know this is immaterial when in use for true macro as MF will be the preferred option but for all other use the AF is pin sharp and fast.

I have also seen complaints posted on how heavy this lens is ! I personally find it to be a good working weight giving good balance hand held with the internal focus also helping greatly in this regard, the ring mount is quickly removed, if its in use mounted on a tripod its just a matter of a half twist and pull of the retaining screw and your hand held and getting on with things “ I love this “ Note that if you have a battery grip or full frame camera you will need to fit the ring mount first as the shoe of the ring mount bottoms out against the camera body preventing its location if that makes sense !!

On a final note I would just like to point out that all the lenses I tried
Canon 180 mm 3.5
Canon 100 f2.8
Tamron 180
Tamron 90
Sigma 180 mm
All are V/Good optics, I think it just comes down to your needs and personal preferences

Yours
Marshall Muir