T3i, 18-55mm, 55-250mm: Will This Package Be Good For Me?

photonius wrote:

macros (small things, like insects) and tele (far away subjects) are two different requirements. Far away subjects need a tele lens, small close subjects need a macro lens. All P&S cameras have a macro mode, for close-up shooting. That's not something that you automatically get with a dSLR lens. That's why a dSLR allows you to change lenses, for each specific application.

Having said that, the 18-55 IS and 55-250 IS lenses are quite good at giving you close up shooting, the smallest subject you can shoot is 67mm wide, good enough usually for flowers.

Here is a calculator

http://www.giangrandi.ch/optics/lenses/focalcalc.html

So, for a 10cm bird, to fill the frame on a 24mm sensor (APS-C), at a distance, you need a 1400mm focal length lens. Have a look at the Canon 800mm lens, the biggest available at present.

I also have a Sony HX20V, which has a nice 25-500mm (full frame equivalent) lens, and gotten shots of birds. However, when cropping, the crop is not as nice like that of a dSLR.

The biggest problem will be shooting through glass window, that could ruin everything.

Have a look at this focal length simulator:

http://www.tamron.eu/en/lenses/focal-length-comparison.html

Roughly, doubling the focal length will double the (zoom in by a factor of 2) the image.