Super telephoto: IS or non-IS (1 Viewer)

I'm looking at 500 and 600mm Canon lenses for birding. Since I plan on using them on tripod only, can I save considerable dollars and buy used lenses without IS? Will that affect the IQ? Any one with experience with these non-IS versions of the lenses?

The issue I would be more concerned about is fixing them if you have a problem. My understanding is that Canon no longer services the non-IS lenses. I believe the non-is lenses are heavier too (the 600 sure is).

But back to your original question the IS will help on the tripod shots. Hard to say how much though.

In bright light and on a tripod you can live without IS. As stated if it breaks though you're in trouble. It's not so much that they don't service them, any authorised repair centre will be able to service the lens, clean it and correct little things etc but if it needs a replacement part that is when you are truly up the creek and you may as well then use it as your paddle.

There is not a lot to break on the non-IS models, so the savings may be worth it. Optical quality is also pretty good. I'd make sure you know who can repair the lens if AF fails - you don't want to buy the lens and then find it fails and can't be repaired. Check with Canon Authorized repair centers or with KEH.com.

For static subjects in lower light, IS is very helpful. That is especially true at under 1/400 second. For birds in flight or other subjects photographed at 1/1000 sec or faster, IS is of little value. IS systems generally do not have long enough time to cycle fully at faster shutter speeds than 1/500 sec.

I am just a novice but I tend to turn IS off these days as I find I don't need to wait for the IS to kick in and stabilise before taking the shot. I shoot from a hide with gimbal head/tripod and with wired remote and often at speeds below 1/100. The results I get with or without IS are not noticeable--to me at least. If Canon still makes long lenses without IS I would sell my IS lenses for one without.
Like the others have mentioned your biggest worry is availability of parts should your AF fail.