Lens Buy with or without "IS" ??

I use the lens on a 6D and 7D mainly for Wildlife / Safari but also plants and portraits. I do not want to bare characteristics of the lens or its top sharpness - received already at full aperture or even the fast and unerring autofocus. Rather, I put here my decision for the IS or against the non-IS version is because (like me) many people ask whether the significant additional cost of IS is worth more than the non-IS.

From me there a clear It's worth it, even in more ways than one! It seems purely external, as the difference lay only in image stabilizer IS. that is not the case. The inner life or the lenses are different in both models and lead the IS to better image quality! Also, the IS is protected against dust and water, which is especially important to me. Apart from the improved optical performance and the weather protection of the image stabilizer is just great! Once you get used to the IS, do not want to give him one. In the evening light, or even with overcast skies or in the forest to get - even at maximum aperture and high ISO in terms of exposure time in the border areas where the image blurred with no luck or Tripod. How effective the IS works, one recognizes only when you turn off this. Then you can already see through the viewfinder, the micro-jitters, even if one tries to keep the lens absolutely quiet, especially at 200mm on APS-C (7D). Thanks to IS is with me hardly a picture here of what is blurred, even if I have to work with low exposure times for lack of light. The 70-200 2.8 USM what the same amount costs about - would be here only a limited alternative because you win only a stop but the IS gives up, who has an efficiency of 4 stops. Even the 2.8 difference already from because of the higher weight and larger dimensions, as I often may establish the tele on holiday.

Conclusion: The 70-200 F4 IS with offers m. E. an added value of the significant additional cost compared to the non-IS more than justifies itself. Better picture quality, dust and splash protection as well as image stabilization can here your heart beat faster. The only flaw I could find is the relatively loud image stabilizer for video recording (with sound) can be disturbing. Still, 5 stars are almost too little.