I have always thought photography was interesting, but it wasn't until I went from the world of the compact cameras to a Canon EOS 40D earlier this year that it became one of my most passionated hobbies. Like many people I have been hanging around this forum reading alot, for about half a year now. It is really helpful to have a resource like this to learn from and get inspiration, and combined with my own experimenting and playing with the camera it is a great way to develop in this great hobby that we all here have in common!
My wonderful 40D combined with my Tamron 28-75 mm lens makes it to the no.1 thing I use/play with whenever I have time, and I always bring it when I am going somewhere. The thing I like most about photography is to take portraits and shooting pictures of people in different situations, and I think that the Tammy lens is most of the times the perfect lens for just that kind of photography. I think it is hard to get a better all-purpose lens for that price!
Now to my question. I have been thinking about what is gonna be the next thing I buy to put on my 40D. I have been searching this forum, and have read a lot about all the lenses there is. I have been interested in buying a Canon 85 mm 1.8 or a 50 mm 1.4 for portraits and low light situations, and also a Sigma 10-20 mm, since I like travelling and would like to get that WA wiew on the photos from my trips.
But recently I ran into a thread here about flashes, and after reading a little bit a thought crossed my mind, if a proper external flash maybe is the right thing to buy next. I don't think I have yet understood the importance of a good flash in photography, and how I would use it to improve my photographing. I almost never use the internal flash since I find it often gives quite unnatural light, and the shadows that sometimes occur behind the objects also destroy the picture. Do you think I can get more out of my photography and learn more by buying a real flash? I read from another thread that a person said he tried to "buy" good pictures with expensive lenses when all he needed was a good flash. A friend of mine also says that the lighting is 70% of the photography.
So, all you expert people, share your experiences about flashes and please tell me why I should buy a flash!
Thanks and have a good day all of you Canon-people! 



