The title does not tell all of what I could use while I wait for my 20D and lense to get back from Canon.
Info or links on 1.6X crop, explaining it.
And what are the best or say not so good choices for a 1.6 cropped camera in the lense dept. To EF or EFS only?
I have a EF70-300 F4-5.6 IS USM. Or say, Canon does for now.
Yes I read my manual. When I get new toys I curl up with it and the book while the battery charges. As green as I am I still need a link to a glossary of terms the book dose not mention.
Regarding lens choices, you need to use the ones you have until you reach their limitations. When you know that you aren't getting shots you want because of not enough focal length, not enough wide angle, not enough close focus, not enough sharpness, or not enough light gathering power, then you will know what you need. I suspect you have a ways to go making more pictures with your equipment yet. You wouldn't expect us to advise you on what kind of girlfriend or boyfriend when you are ready to trade one in, would you. Your needs are personal, and until you can specifically articulate needs for lenses, then you don't need more lenses.
1.6 crop factor is linear dimensionally. So multiply focal lengths by 1.6 to get the equivalent focal lengths on full-frame. Your 70-300mm is the equivalent to a 112-480mm focal length zoom on full-frame (35mm film size or sensor size).
Wide Open = lens aperture (diaphragm blades) wide open, smallest f-stop setting (ex. f/4 on the 70-300mm)
Barrel Distortion = lens distortion that bows verticals and horizontals outwards towards the edge of frames.
This book will explain pretty much everything bar the 1.6x crop. It also explains how focal length and film size (sensor size for digital) relate to field of view, perspective alteration etc. From that point the concept of a crop sensor multiplying the "effective focal length" of a lens for field of view only becomes much clearer.