Al Kaplan
Veteran
First you need to figure out how YOU see the world. Spend a day walking around and finding pictures to take, both from the standpoint of the area covered and from the correct distance to give you the correct relationship of foreground to back ground. All you need is a camera with multiple frame lines handy, no film, no lens. Now look through the finder and see which frame line matches up with what you're seeing. Some people mostly "see 35", others "see 100", or whatever. The focal length that best matches YOUR outlook on the world should be your main lens. Pick other lenses, wider or narrower, as needed. Then practice learning what they cover. At some point you'll be able to pick the exact lens you need for a given shot without giving it a second thought. A 35 and a 90 should cover you for better than 90% of your needs. Then add a 21 and finally a 180. Most people really have to look for excuses to justify longer or wider. Also consider that rather than blowing all that money on every piece of glass that intrigues you you might be better off buying more bodies with the money. Changing lenses is a royal pain. Far easier to just grab the camera with the correct lens. Run out of film in the body with the lens you're using? Practice grabbing one lens in each hand and pressing the lens release buttons with your thumbs, switch the lenses between bodies, and you're good to go! Practice The Big Switch while running or jostling your way through a crowd...LOL. Change film when the action slows down. Sometimes it makes sense to change film when you've gotten up to 30 or beyond rather than waiting for 36. Better to lose a few frames than miss an important shot because you ran out.