IS or not to IS?

[bribears]

I bought a telephoto zoom lens with IS on it because I thought it would give me better pictures. After reading stuff on this site for a month now and loving the pictures that my telephoto is taking I wonder, am I sacrificing the potential of my pictures as well as my ability to learn manual modes because I have an IS lens?

[Elmo]

IS has nothing to do with focusing. Also If concerned about effects you can turn IS off.

[kirbinster]

The only thing IS (or VR) does is reduce the impact of motion blur caused by your hands shaking. ITs should not adversely impact the picture. As said, you can always turn it off to check for yourself.

[DeltaRay]

like the earlier poster said the best way to test is to turn IS off and then on then compare

[inkista]

All that IS may be keeping you from learning properly is good handholding technique and just how slow the shutter speed can be without it.

The rule of thumb (without IS) is that you need a shutter speed of 1/focal_length or faster. So, for a 200mm lens, that means 1/200s. IS gives you a two or three stop advantage, so the limit would (theoretically, depends on your handholding skills and which generation of IS you've got), be 1/50s (two stop) or 1/25s (three stop) with a 200mm lens.

Handholding technique, though, you're on your own.