Extension tubes

[mark_farrell]

I've tried a few different methods of macrophotography, but one still eludes me - butterflies and dragonflies. I'm considering a 180 f/3.5L, but was wondering how comparable the use of extension tubes on a 70-200 f/4.0 L would be?

I know extension tubes are used to reduce minimum focal distance at the expense of infinity focus, but what sort of distances can a 'normal' lens be focussed to with tubes?

[Canon Bob]

Using the 70-200/4 with a 25mm tube as a guide, you'll get around 0.42x magnification at the wide end although the working distance range is pretty restrictive. At the long end then the magnification drops to 0.3x but the minimum focus distance range is improved....956-1730mm between MFD and infinity focus settings.

Bob

[arclight]

You'll get in very very close with tubes, but butterflies tend not to like that and fly off.

[Canon Bob]

You'll get in very very close with tubes, but butterflies tend not to like that and fly off.
Agreed, the 300/4 IS L is the perfect tool for the job.

Bob

[mark_farrell]

Yes that was my worry... Never having used tubes, I wasn't sure what sort of magnification ratio / mfd implications they had

300/4 IS L is the perfect tool for the job.

Bugger, not another Big lens to add to my 'to buy' list, let alone carry!