Canon EF-S 55-250mm IS Lens. I need some help specifically about the Image Stabilisation from Pro/enthusiasts

I am seriously considering buying this lens. I understand the 4 stops theory but how does this work in practice. Give me specific examples of how this lens could take pictures that I could not achieve another way with a non IS lens. I already have a non IS usm zoom covering a similar range so am I just 'wasting cash'? I am interested because I want to do low light hand held photography and would prefer not to use a flash which I think ruins the atmosphere? Am I right in thinking that night shots should be done with the flash off? Can you also recommend a book on low light hand held photography as I rarely carry my tripod (although I know I should) as it is just too inconvienient. Thanks

In practice it is more like a two to three stop advantage (this depends upon the focal length of the lens).

Most sports and nature photographers have long ago learned how to stabilize their cameras using various techniques. Now with IS and VR, they have one more tool. If you combine traditional stabilization techniques with the IS/VR technology you have the best of both worlds.

You can never "waste cash" when purchasing lenses for your camera system .. as long as you stay with the lenses made by your camera company ... these lenses will last for decades, long after you have purchased many replacement DSLR camera bodies..

Low-light, hand-held photography is precisely the purpose of IS, so you're not wasting cash.

However, remember that IS will not reduce subject motion blur -- only camera motion blur.

It's up to you whether to use flash or not...that's a creative decision.

Search Amazon for books.

HTH
V2K1

My advice may not address your question about IS specifically, but I hope to give you another option to consider.

If your budget is limited, instead of buying an IS lens with similar range to what you already have, I would suggest buying an external flash and diffuser/bounce card, and learn the bounce flash technique. This will allow you take pictures in low light situations while retaining the atmosphere.

And for scenary night shots, get a good tripod.

IS has it's advantages, for example long range photography in the outdoors or in situations where flash is simply not permitted. but with a flash, you're not "locked" in a certain range. You can use the flash with any lens.