need an opinion about the canon ef 70-200mm f/4 L USM lens. Is it necessary to get the IS version?

It depends. What are you shooting? I am doing night shots and daytime landscapes. I plan on using a tripod most of the time, so the IS will not be needed. And to the person who stated the IS optics are better than the non IS, could you please provide a link to where you read this? My understanding is there is no difference aside from the image stabilization.