dust - like what others have mentioned, when spots start appearing in the sky. altenratively, find a relatively uniformly colored wall, preferably white, set to aperture priority mode, ev +1 at f/22, manual focus, and make sure the wall texture is out of focus, (usually taken from a distance away, and set to nearest focal distance).. then you can see all your dust bunnies.
noise - a separate issue altogether. most modern dslrs can handle noise well up to iso800. no need to pixel peep, even prints can look good, sometimes we just ask too much out of cameras. of course, if that is an issue, just stick to shooting at lowest iso possible anytime.
maintenance of dslr - you ahve to replace the shutter now and then, 400d is rated at 50K shots, if i am not wrong, but this is just a guide, the shutter can die anytime it wants to, depends on your luck. you can easily clean the sensor yourself, with the appropriate tools, no need to go to servicing centre all the time.
noise - a separate issue altogether. most modern dslrs can handle noise well up to iso800. no need to pixel peep, even prints can look good, sometimes we just ask too much out of cameras. of course, if that is an issue, just stick to shooting at lowest iso possible anytime.
maintenance of dslr - you ahve to replace the shutter now and then, 400d is rated at 50K shots, if i am not wrong, but this is just a guide, the shutter can die anytime it wants to, depends on your luck. you can easily clean the sensor yourself, with the appropriate tools, no need to go to servicing centre all the time.
