Choosing a macro lens

I hope this may prove of interest or indeed value to BPN folk with a keen interest in macro photography. I have decided at last upon which lens to purchase, my main interests are insect photography. I have recently field tested Sigma 150mm, Sigma 180mm plus combining them with the 1.4x TC and the 2x TC.
The 150mm plus 1.4 TC will AF, with the 2x TC it will not (at least consistently).
The 180mm with either TC will not AF.
To cut a story short the 180mm gives a longer working distance , i.e. the distance from the film plane and the subject BUT this is nothing like as much an advantage as you might imagine! The 180mm lens is considerably longer and the lens hood is also correspondingly longer, so when you look at the distance from the lens hood to the subject you only gain about 13mm when at 1:1.
The Sigma 150mm is noticeably lighter and smaller than the 180mm and when coupled with the 1.4TC it makes a super combination and of course the working distance is increased, in fact it is greater then that of the 180mm alone.
Purchasing the 150mm with the 1.4 which you may not always need but gives great flexibility seems to me to be the most efficient way of spending money.

I decided I would buy the 150mm plus 1.4TC, then I thought again and I have decided to buy the Canon 180mm. It is much more expensive and is no better optically. Why? The big plus for me is that AF will work with the Canon 1.4 TC in combination. I know a lot of people still focus manually but I am absolutely sold on AF purely from an accuracy point of view, (I often AF, then lock focus and if required recompose slightly) and to be able to have AF with an effective 250mm or so macro lens is a very powerful combination.
Jon

HI Jonathan You did your homework and came up with a the best solution for your needs. That is what it boils down to !!!

I have the Sigma 150 which is used with the dedicated converter just about all the time. I have found the lens as sharp as the Canon/Nikon and lighter. It is the only non brand name lens I own. btw the focusing (AF) is a non issue since you are much better off going manual an rocking the lens back and forth as it comes into focus.

Now that you have the lens might want to consider diffusers !!!! Will make all the difference in the world !!!

Hi Al,
yes I did rock back and forth in the old days when I was manual focus but I use servo AF - guess what it works! Never thought it owuld but it does. Any lack of sharpness I experience I reckon is due to me not using a tripod. I tend to do most macro work now using a monopod, when possible I will use a tripod and use the mirror lock up custom function but this is not always practicable. Have a go at servo Af, I think you will be suprised!
Jon

I have Jonathan but it is not as accurate. Also when you have extension tubes it becomes even worse. The AF will also hunt back and forth depending on bg and contrast. Its a no go for me most of the time.

Most of my macro deals with bugs, do also flowers but not as much !!!

Hi Jon,

Macro with Sevo AF works well for flying insects, bees etc. I have used it down to 1:1. Results are really depend on the lens, and your settings, esp focus tracking speed.

Robert

I'll often use the auto-focus to get it in the right area and then manually tweak it to where I need.

The Canon lens is awesome!