I´ve been looking at the Canon Zoom EF 70-200 mm 2.8 IS II USM online and it looks really good, but from what I read it´s plain out silly to combine it with the camera I have? Do I also need a new body?
As someone who has combined a 70-200 f/2.8 IS II with a 450D, I can confirm that it feels a bit silly! But that's mainly due to the odd weight/size balance - you'll still get superb results with your photos from this lens with the 450D.
I think it might be worth quickly brushing over
why you got such bad results when shooting rhythmic gymnastics with that lens/camera combo, if you aren't already aware. Firstly, I'll assume that most of your shots were a) out of focus and b) blurred due to motion. I'll deal with the limitations of the camera and the lens (for this application) seperately:
Camera- The 450D has poor AI Servo focus - this means it struggles to keep the lens focused on moving subjects
- Slow burst rate (as mentioned by scrappydog); if you're firing off 3 frames per second you're less likely to get the shot than if you're firing 8
- 1600 maximum ISO - if you're trying to push your ISO higher to get a fast enough shutter speed to freeze action, you'll hit the cap at a rather meager (and noisy) ISO 1600
Lens - assuming 70-200 is the right focal length; this is really your call
- f/4.5-5.6 means that at 70mm, the maximum aperture is f/4.5 and at 200mm the maximum aperture is f/5.6 - neither of these are normally considered fast enough for sports, i.e. they don't let enough light in. I consider f/2.8 to be a minimum for sports, and for some indoor sports even this is not enough. A wider aperture also helps to blur the background and give separation to your subject.
- ... okay maybe that's the only one. Image Stabilization doesn't really help for sports because you're already using shutter speeds that should be fast enough to freeze motion (upwards of 1/500sec, preferably 1/1000sec). One thing it is useful for is panning.
Flash can also be really helpful for freezing motion, although it's generally not preferred because it's distracting and it prevents you from using high burst rates. Here's an example of a gymnastics photo I took with flash:
(Canon 7D + 17-55 f/2.8 IS)Anyhow... to get back to your original question, which wasn't really about sports shooting - The 450D is a perfectly acceptable camera for travel as long as you aren't expecting to run into any scenarios demanding high burst rates, AI Servo focus tracking or high ISO. I really like the 450D + 50mm 1.4 (1.8 if you're on a budget) as a compact travel kit that fits my style of photography.
EDIT: My mistake, that photo was actually taken with the EF-S 17-55 f/2.8 IS.