I want to take concert photos and night photos, and of course there will be low-light. I don't want to use the flash. I won't be using a tripod for the concerts photos, and the camera does not have an Image Stabilizer. 1st: Can this be done? When zooming big, I want to maintain a wide aperture, but every time I zoom the aperture doesn't stay wide, it changes to the next higher aperture. For example: I want it to stay at 3.5, but when I zoom it goes to 4, 4.5, 5, 5.6, 6, 6.3. 2nd: When I'm in A mode, I can only adjust the aperture, but not shutter. When I'm in S mode, I can only adjust the shutter, but not aperture. Is there a mode that I can use to change both the aperture and shutter? 3rd: My camera goes up to ISO 3200. Which is the best to use for a concert and for night cityscapes? What type of effect will the ISO have on the aperture and shutter speed? I have been reading the manual, but the manual only gives so much information. Maybe someone can suggest me a good book in aperture, shutter speed, exposure...and well, you know a beginner's guide with in-depth information? Thanks in advance.