View Full Version : A couple of questions about IS

2nd February 2010, 03:04 PM
Sorry, I bet your all wishing I never found this forum as I just keep asking for information :o Firstly, how does the IS system work? Secondly, if the ISO is set to AUTO does the camera take into account if you have the IS switched on? (for example, would it pick a lower ISO if IS was on, or would this not come into the equation?) Thirdly, are there any disadvantages to having IS switched on?

Kiwi Paul
2nd February 2010, 03:21 PM
The IS system takes into account any camera movement and effectively cancels this out meaning you can take photos using shutter speeds lower than you can without it (approx 2 to 3 stops slower) and avoid blur caused by camera movement.
I don't believe the ISO and IS systems are linked.
The only times it should be turned off is when using a tripod or if you are panning on a moving subject and want to blur the background.

IS1 corrects movement in vertical and horozontal planes, IS2 only corrects for vertical movement allowing you to pan and still achieve background blur.


2nd February 2010, 05:05 PM
I think what you are asking regarding ISO is whether when you are shooting in A mode with auto ISO the camera will select a longer shutter speed and lower ISO if you have IS on?

I believe the relationships are pre set and that it doesn't. arguably it shouldn't either because camera shake is a small part of the overall shooting equation.

The solution in any event is to shoot M with auto ISO and take control of the shutter speed. This has the alternative advantage of effectively putting ISO directly on the control wheel as the corollary of shutter speed.