Telelens advice

[Bert]

Last summer, I bought the Canon EOS 350D.
Now I'm looking for a zoomlens and for some advice...

I borrowed a Canon 75-300 f/4-5.6 from a colleague. Makes some good pics. Costs €189 at www.foto-konijnenberg.nl Can't find it cheaper.

But I'm willing to pay a bit more...

The Canon 75-300 f/4-5.6 USM (€198 at http://www.foto-konijnberg.nl) and the Canon 75-300 f/4-5.6 IS USM (€575 at http://www.cornevaniperen.nl) are also interesting, but is it worth to buy one of these more expensive lenses? Do I really need the USM and the IS for spotting?

Are there good alternatives from SIGMA?

I do not know much about lenses... so maybe someone can help me out, and give me some tips where to buy.

I loved the BIGMA from Fabke @ Koksijde... but it's a bit too expensive for me... ;D

[Vonsmalhausen]

bert said:

Do I really need the USM and the IS for spotting?

USM yes, IS not really.
USM is very important to focus quick ( keep in mind that a plane moves fast )
IS is only of use if you want to photograph a lot of propeller planes, it helps a lot in reducing the shutter-speed to get a "moving" effect from the props, and still have a sharp pic without "motion blurr" (shaking hands and stuff like that)
so if you take mostly jets, you will never use IS ; here you need a high shutter-speed : 1/500 and plus, and this gives you sharp pics without IS. ( in fact, i think that IS is not working when you have speeds over 1/250 )
more info about lenses you can find here forum.belgiumdigital.com/index.php, those people can tell you a lot more than i could