Aerial photography...Is an IS lens necessary?

I plan to get a 70-200 F4L lens and will be doing aerial photography occasionally. Otherwise, all the other shots will be outside in good light (I know, aerial photography is outside too).

I would like the opinion of those who do aerial photography as to whether the IS feature is worth the extra $600. Hate to spend the extra $$$ if I don't have to.

Camera is a 50D.

Thanks

Provided you fly in benign conditions very early in the morning or very late in the evening and you are ok with faster shutter speeds, no, you do not have to have IS.

It's probably not, but I would still get the IS version. Are you only using the lens for Aerial photography? Thing is the IS version has upgraded optics and is sharper than the non-IS. IS is always useful, i mean it's always better to have it than not. You can always turn IS off if you don't need it whereas you can't turn IS on if you have a non-IS.

I've seen too many ppl buying the non-IS to save money initially and later regret and upgrade to IS.

Get the best you can afford.

Spend it, test it and return it if not needed. Works every time.

I've been up in a helicopter a couple of times. I guess it depends on the aircraft, but you can get some high frequency vibration that an IS does a good job of helping with.

IS does stabilize the viewfinder as well - it's not only for the final results!