SOS – EF 100 – 400mm IS Lens

The IS is nothing to do with the image. The lens has sensors in it that detect physical movement, one vertically and one horizontally. These then move one of the internal lens groups to compensate for the small amounts of shake and so keep the image stable.

Mode 2 should be used for panning as it disables the horizontal sensor and so doe not try and fight the movement you are making but will compensate for the shake in the vertical axis.

An easy way to see the IS effect is the focus on a small object close up at full zoom and then watch it hop around in the view finder. Now swithch on the IS and watch it lock-on. Mode 2 will give movement in one axis only.

More information here Canon IS Lens Guide

Jeff

Cheers Robbo

I wondered how it worked – now I know!

it all makes sense now!

Paulc – yeah and before I remembered which setting to have it on I got many bad shots!!! – but the thing I was wondering was how does the IS work?

is it in relation to the background – so in position 2 when you are panning it ignores the moving background – but what I was thinking was if you have a perfect clear blue sky there would not be a background for the system to relate to – therfore in theory you could leave on position 1???

I tried this and it doesnt seem to work – but I was just wondering ‘how it does it’!!

Richb,

if you leave the lens in mode 1 when panning you are constantly fighting against the IS doing its job – so it is easier to use mode 2 when panning (or at airshows in general)

On this subject – if you have a clear blue sky behind (ie no background so to speak) could you get away with mode one while panning??

Would you gain anything or whould it not work??

Or am I being thick in my asumption that it will only really work when there is a background!?

Thanks Rob, I had misplaced the book for the Lens and my mind had gone completely blank!

Eric