I don't mean to imply that I've chosen the best route, but here's what I've wound up with and why.
My first priority on a new lens was for non-flash, lower light people and central subject shots; at home, in Bistros, theater, museum, etc.
For this I got a 50mm F:1.7. I think it might be the last lens I'd give up as it will be successful in a very broad range of lighting conditions; ie. it can always be stopped down when there's enough light, but my other lenses aren't so fast & often can't be opened wide enough. Even though I've difficulty in zooming with my feet due to physical limitations, the fast fifty at least makes a lot of shots possible (maybe I'll have to foot zoom, but at least it is possible.).
Lens aperture has often been limiting for my choice of subjects; when using a long lens for wildlife I can't hand-hold unless the shutter speed is high; but the speed can't be high with a slow lens. This problem is compounded at dusk, dawn, and in the forest.
Unlike many others, I find scant use for wide angles as I tend to emphasize a subject when I frame a photo - usually I fill the frame with a subject, so my 18-55mm kit lens gets little use at the wide end. The lenses in my knock-about bag now are Tamron 28-75mm F2.8, Pentax DA 55-300 F4-5.8, Pentax F 55mm F1.7, Raynox DCR 150 for impulse close-ups, & a 1.5X teleconverter.
I'd dearly love a faster long zoom lens but haven't found anything suitable in weight* or cost yet. I use a manual Soligor 200mm F2.8 for situations demanding longer reach in lower light; a 1.5x converter stretches that to 300mm f4 when needed.
Dave in Iowa
*I'd love to find a plastic Beer-Can Zoom maybe 70-300mm F2.8-4. (75-300mm F:2-4 should be possible I think....Oooo!)
Last edited by newarts; 08-01-2009 at 06:46 AM.